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jeremybenn |
/*
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* Written by Doug Lea with assistance from members of JCP JSR-166
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* Expert Group and released to the public domain, as explained at
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* http://creativecommons.org/licenses/publicdomain
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*/
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package java.util.concurrent;
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import java.util.*;
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import java.util.concurrent.atomic.*;
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/**
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* A scalable concurrent {@link ConcurrentNavigableMap} implementation.
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* The map is sorted according to the {@linkplain Comparable natural
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* ordering} of its keys, or by a {@link Comparator} provided at map
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* creation time, depending on which constructor is used.
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*
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* <p>This class implements a concurrent variant of <a
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* href="http://www.cs.umd.edu/~pugh/">SkipLists</a> providing
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* expected average <i>log(n)</i> time cost for the
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* <tt>containsKey</tt>, <tt>get</tt>, <tt>put</tt> and
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* <tt>remove</tt> operations and their variants. Insertion, removal,
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* update, and access operations safely execute concurrently by
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* multiple threads. Iterators are <i>weakly consistent</i>, returning
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* elements reflecting the state of the map at some point at or since
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* the creation of the iterator. They do <em>not</em> throw {@link
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* ConcurrentModificationException}, and may proceed concurrently with
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* other operations. Ascending key ordered views and their iterators
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* are faster than descending ones.
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*
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* <p>All <tt>Map.Entry</tt> pairs returned by methods in this class
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* and its views represent snapshots of mappings at the time they were
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* produced. They do <em>not</em> support the <tt>Entry.setValue</tt>
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* method. (Note however that it is possible to change mappings in the
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* associated map using <tt>put</tt>, <tt>putIfAbsent</tt>, or
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* <tt>replace</tt>, depending on exactly which effect you need.)
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*
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* <p>Beware that, unlike in most collections, the <tt>size</tt>
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* method is <em>not</em> a constant-time operation. Because of the
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* asynchronous nature of these maps, determining the current number
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* of elements requires a traversal of the elements. Additionally,
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* the bulk operations <tt>putAll</tt>, <tt>equals</tt>, and
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* <tt>clear</tt> are <em>not</em> guaranteed to be performed
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* atomically. For example, an iterator operating concurrently with a
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* <tt>putAll</tt> operation might view only some of the added
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* elements.
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*
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* <p>This class and its views and iterators implement all of the
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* <em>optional</em> methods of the {@link Map} and {@link Iterator}
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* interfaces. Like most other concurrent collections, this class does
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* <em>not</em> permit the use of <tt>null</tt> keys or values because some
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* null return values cannot be reliably distinguished from the absence of
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* elements.
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*
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* <p>This class is a member of the
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* <a href="{@docRoot}/../technotes/guides/collections/index.html">
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* Java Collections Framework</a>.
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*
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* @author Doug Lea
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* @param <K> the type of keys maintained by this map
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* @param <V> the type of mapped values
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* @since 1.6
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*/
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public class ConcurrentSkipListMap<K,V> extends AbstractMap<K,V>
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implements ConcurrentNavigableMap<K,V>,
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Cloneable,
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java.io.Serializable {
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/*
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* This class implements a tree-like two-dimensionally linked skip
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* list in which the index levels are represented in separate
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* nodes from the base nodes holding data. There are two reasons
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* for taking this approach instead of the usual array-based
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* structure: 1) Array based implementations seem to encounter
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* more complexity and overhead 2) We can use cheaper algorithms
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* for the heavily-traversed index lists than can be used for the
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* base lists. Here's a picture of some of the basics for a
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* possible list with 2 levels of index:
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*
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* Head nodes Index nodes
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* +-+ right +-+ +-+
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* |2|---------------->| |--------------------->| |->null
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* +-+ +-+ +-+
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* | down | |
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* v v v
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* +-+ +-+ +-+ +-+ +-+ +-+
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* |1|----------->| |->| |------>| |----------->| |------>| |->null
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* +-+ +-+ +-+ +-+ +-+ +-+
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* v | | | | |
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* Nodes next v v v v v
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* +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+
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* | |->|A|->|B|->|C|->|D|->|E|->|F|->|G|->|H|->|I|->|J|->|K|->null
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* +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+ +-+
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*
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* The base lists use a variant of the HM linked ordered set
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* algorithm. See Tim Harris, "A pragmatic implementation of
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* non-blocking linked lists"
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* http://www.cl.cam.ac.uk/~tlh20/publications.html and Maged
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* Michael "High Performance Dynamic Lock-Free Hash Tables and
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* List-Based Sets"
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* http://www.research.ibm.com/people/m/michael/pubs.htm. The
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* basic idea in these lists is to mark the "next" pointers of
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* deleted nodes when deleting to avoid conflicts with concurrent
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* insertions, and when traversing to keep track of triples
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* (predecessor, node, successor) in order to detect when and how
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* to unlink these deleted nodes.
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*
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* Rather than using mark-bits to mark list deletions (which can
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* be slow and space-intensive using AtomicMarkedReference), nodes
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* use direct CAS'able next pointers. On deletion, instead of
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* marking a pointer, they splice in another node that can be
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* thought of as standing for a marked pointer (indicating this by
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* using otherwise impossible field values). Using plain nodes
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* acts roughly like "boxed" implementations of marked pointers,
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* but uses new nodes only when nodes are deleted, not for every
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* link. This requires less space and supports faster
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* traversal. Even if marked references were better supported by
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* JVMs, traversal using this technique might still be faster
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* because any search need only read ahead one more node than
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* otherwise required (to check for trailing marker) rather than
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* unmasking mark bits or whatever on each read.
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*
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* This approach maintains the essential property needed in the HM
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* algorithm of changing the next-pointer of a deleted node so
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* that any other CAS of it will fail, but implements the idea by
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* changing the pointer to point to a different node, not by
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* marking it. While it would be possible to further squeeze
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* space by defining marker nodes not to have key/value fields, it
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* isn't worth the extra type-testing overhead. The deletion
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* markers are rarely encountered during traversal and are
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* normally quickly garbage collected. (Note that this technique
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* would not work well in systems without garbage collection.)
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*
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* In addition to using deletion markers, the lists also use
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* nullness of value fields to indicate deletion, in a style
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* similar to typical lazy-deletion schemes. If a node's value is
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* null, then it is considered logically deleted and ignored even
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* though it is still reachable. This maintains proper control of
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* concurrent replace vs delete operations -- an attempted replace
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* must fail if a delete beat it by nulling field, and a delete
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* must return the last non-null value held in the field. (Note:
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* Null, rather than some special marker, is used for value fields
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* here because it just so happens to mesh with the Map API
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* requirement that method get returns null if there is no
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* mapping, which allows nodes to remain concurrently readable
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* even when deleted. Using any other marker value here would be
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* messy at best.)
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*
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* Here's the sequence of events for a deletion of node n with
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* predecessor b and successor f, initially:
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*
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* +------+ +------+ +------+
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* ... | b |------>| n |----->| f | ...
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* +------+ +------+ +------+
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*
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* 1. CAS n's value field from non-null to null.
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* From this point on, no public operations encountering
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* the node consider this mapping to exist. However, other
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* ongoing insertions and deletions might still modify
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* n's next pointer.
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*
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* 2. CAS n's next pointer to point to a new marker node.
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* From this point on, no other nodes can be appended to n.
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* which avoids deletion errors in CAS-based linked lists.
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*
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* +------+ +------+ +------+ +------+
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* ... | b |------>| n |----->|marker|------>| f | ...
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* +------+ +------+ +------+ +------+
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*
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* 3. CAS b's next pointer over both n and its marker.
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* From this point on, no new traversals will encounter n,
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* and it can eventually be GCed.
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* +------+ +------+
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* ... | b |----------------------------------->| f | ...
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* +------+ +------+
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*
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* A failure at step 1 leads to simple retry due to a lost race
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* with another operation. Steps 2-3 can fail because some other
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* thread noticed during a traversal a node with null value and
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* helped out by marking and/or unlinking. This helping-out
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* ensures that no thread can become stuck waiting for progress of
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* the deleting thread. The use of marker nodes slightly
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* complicates helping-out code because traversals must track
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* consistent reads of up to four nodes (b, n, marker, f), not
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* just (b, n, f), although the next field of a marker is
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* immutable, and once a next field is CAS'ed to point to a
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* marker, it never again changes, so this requires less care.
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*
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* Skip lists add indexing to this scheme, so that the base-level
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* traversals start close to the locations being found, inserted
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* or deleted -- usually base level traversals only traverse a few
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* nodes. This doesn't change the basic algorithm except for the
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* need to make sure base traversals start at predecessors (here,
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* b) that are not (structurally) deleted, otherwise retrying
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* after processing the deletion.
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*
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* Index levels are maintained as lists with volatile next fields,
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* using CAS to link and unlink. Races are allowed in index-list
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* operations that can (rarely) fail to link in a new index node
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* or delete one. (We can't do this of course for data nodes.)
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* However, even when this happens, the index lists remain sorted,
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* so correctly serve as indices. This can impact performance,
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* but since skip lists are probabilistic anyway, the net result
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* is that under contention, the effective "p" value may be lower
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* than its nominal value. And race windows are kept small enough
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* that in practice these failures are rare, even under a lot of
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* contention.
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*
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* The fact that retries (for both base and index lists) are
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* relatively cheap due to indexing allows some minor
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* simplifications of retry logic. Traversal restarts are
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* performed after most "helping-out" CASes. This isn't always
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* strictly necessary, but the implicit backoffs tend to help
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* reduce other downstream failed CAS's enough to outweigh restart
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* cost. This worsens the worst case, but seems to improve even
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* highly contended cases.
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*
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* Unlike most skip-list implementations, index insertion and
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* deletion here require a separate traversal pass occuring after
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* the base-level action, to add or remove index nodes. This adds
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* to single-threaded overhead, but improves contended
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* multithreaded performance by narrowing interference windows,
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* and allows deletion to ensure that all index nodes will be made
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* unreachable upon return from a public remove operation, thus
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* avoiding unwanted garbage retention. This is more important
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* here than in some other data structures because we cannot null
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* out node fields referencing user keys since they might still be
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* read by other ongoing traversals.
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*
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* Indexing uses skip list parameters that maintain good search
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* performance while using sparser-than-usual indices: The
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* hardwired parameters k=1, p=0.5 (see method randomLevel) mean
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* that about one-quarter of the nodes have indices. Of those that
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* do, half have one level, a quarter have two, and so on (see
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* Pugh's Skip List Cookbook, sec 3.4). The expected total space
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* requirement for a map is slightly less than for the current
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* implementation of java.util.TreeMap.
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*
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* Changing the level of the index (i.e, the height of the
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* tree-like structure) also uses CAS. The head index has initial
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* level/height of one. Creation of an index with height greater
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* than the current level adds a level to the head index by
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* CAS'ing on a new top-most head. To maintain good performance
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* after a lot of removals, deletion methods heuristically try to
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* reduce the height if the topmost levels appear to be empty.
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* This may encounter races in which it possible (but rare) to
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* reduce and "lose" a level just as it is about to contain an
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* index (that will then never be encountered). This does no
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* structural harm, and in practice appears to be a better option
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* than allowing unrestrained growth of levels.
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*
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* The code for all this is more verbose than you'd like. Most
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* operations entail locating an element (or position to insert an
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* element). The code to do this can't be nicely factored out
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* because subsequent uses require a snapshot of predecessor
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* and/or successor and/or value fields which can't be returned
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* all at once, at least not without creating yet another object
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* to hold them -- creating such little objects is an especially
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* bad idea for basic internal search operations because it adds
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* to GC overhead. (This is one of the few times I've wished Java
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* had macros.) Instead, some traversal code is interleaved within
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* insertion and removal operations. The control logic to handle
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* all the retry conditions is sometimes twisty. Most search is
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* broken into 2 parts. findPredecessor() searches index nodes
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* only, returning a base-level predecessor of the key. findNode()
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* finishes out the base-level search. Even with this factoring,
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* there is a fair amount of near-duplication of code to handle
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* variants.
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*
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* For explanation of algorithms sharing at least a couple of
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* features with this one, see Mikhail Fomitchev's thesis
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* (http://www.cs.yorku.ca/~mikhail/), Keir Fraser's thesis
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* (http://www.cl.cam.ac.uk/users/kaf24/), and Hakan Sundell's
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* thesis (http://www.cs.chalmers.se/~phs/).
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*
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* Given the use of tree-like index nodes, you might wonder why
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* this doesn't use some kind of search tree instead, which would
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* support somewhat faster search operations. The reason is that
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* there are no known efficient lock-free insertion and deletion
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* algorithms for search trees. The immutability of the "down"
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* links of index nodes (as opposed to mutable "left" fields in
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* true trees) makes this tractable using only CAS operations.
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*
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* Notation guide for local variables
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* Node: b, n, f for predecessor, node, successor
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* Index: q, r, d for index node, right, down.
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* t for another index node
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* Head: h
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* Levels: j
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* Keys: k, key
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* Values: v, value
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* Comparisons: c
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*/
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private static final long serialVersionUID = -8627078645895051609L;
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/**
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* Generates the initial random seed for the cheaper per-instance
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* random number generators used in randomLevel.
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*/
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private static final Random seedGenerator = new Random();
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/**
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* Special value used to identify base-level header
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*/
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private static final Object BASE_HEADER = new Object();
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/**
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* The topmost head index of the skiplist.
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*/
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private transient volatile HeadIndex<K,V> head;
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310 |
|
|
|
311 |
|
|
/**
|
312 |
|
|
* The comparator used to maintain order in this map, or null
|
313 |
|
|
* if using natural ordering.
|
314 |
|
|
* @serial
|
315 |
|
|
*/
|
316 |
|
|
private final Comparator<? super K> comparator;
|
317 |
|
|
|
318 |
|
|
/**
|
319 |
|
|
* Seed for simple random number generator. Not volatile since it
|
320 |
|
|
* doesn't matter too much if different threads don't see updates.
|
321 |
|
|
*/
|
322 |
|
|
private transient int randomSeed;
|
323 |
|
|
|
324 |
|
|
/** Lazily initialized key set */
|
325 |
|
|
private transient KeySet keySet;
|
326 |
|
|
/** Lazily initialized entry set */
|
327 |
|
|
private transient EntrySet entrySet;
|
328 |
|
|
/** Lazily initialized values collection */
|
329 |
|
|
private transient Values values;
|
330 |
|
|
/** Lazily initialized descending key set */
|
331 |
|
|
private transient ConcurrentNavigableMap<K,V> descendingMap;
|
332 |
|
|
|
333 |
|
|
/**
|
334 |
|
|
* Initializes or resets state. Needed by constructors, clone,
|
335 |
|
|
* clear, readObject. and ConcurrentSkipListSet.clone.
|
336 |
|
|
* (Note that comparator must be separately initialized.)
|
337 |
|
|
*/
|
338 |
|
|
final void initialize() {
|
339 |
|
|
keySet = null;
|
340 |
|
|
entrySet = null;
|
341 |
|
|
values = null;
|
342 |
|
|
descendingMap = null;
|
343 |
|
|
randomSeed = seedGenerator.nextInt() | 0x0100; // ensure nonzero
|
344 |
|
|
head = new HeadIndex<K,V>(new Node<K,V>(null, BASE_HEADER, null),
|
345 |
|
|
null, null, 1);
|
346 |
|
|
}
|
347 |
|
|
|
348 |
|
|
/** Updater for casHead */
|
349 |
|
|
private static final
|
350 |
|
|
AtomicReferenceFieldUpdater<ConcurrentSkipListMap, HeadIndex>
|
351 |
|
|
headUpdater = AtomicReferenceFieldUpdater.newUpdater
|
352 |
|
|
(ConcurrentSkipListMap.class, HeadIndex.class, "head");
|
353 |
|
|
|
354 |
|
|
/**
|
355 |
|
|
* compareAndSet head node
|
356 |
|
|
*/
|
357 |
|
|
private boolean casHead(HeadIndex<K,V> cmp, HeadIndex<K,V> val) {
|
358 |
|
|
return headUpdater.compareAndSet(this, cmp, val);
|
359 |
|
|
}
|
360 |
|
|
|
361 |
|
|
/* ---------------- Nodes -------------- */
|
362 |
|
|
|
363 |
|
|
/**
|
364 |
|
|
* Nodes hold keys and values, and are singly linked in sorted
|
365 |
|
|
* order, possibly with some intervening marker nodes. The list is
|
366 |
|
|
* headed by a dummy node accessible as head.node. The value field
|
367 |
|
|
* is declared only as Object because it takes special non-V
|
368 |
|
|
* values for marker and header nodes.
|
369 |
|
|
*/
|
370 |
|
|
static final class Node<K,V> {
|
371 |
|
|
final K key;
|
372 |
|
|
volatile Object value;
|
373 |
|
|
volatile Node<K,V> next;
|
374 |
|
|
|
375 |
|
|
/**
|
376 |
|
|
* Creates a new regular node.
|
377 |
|
|
*/
|
378 |
|
|
Node(K key, Object value, Node<K,V> next) {
|
379 |
|
|
this.key = key;
|
380 |
|
|
this.value = value;
|
381 |
|
|
this.next = next;
|
382 |
|
|
}
|
383 |
|
|
|
384 |
|
|
/**
|
385 |
|
|
* Creates a new marker node. A marker is distinguished by
|
386 |
|
|
* having its value field point to itself. Marker nodes also
|
387 |
|
|
* have null keys, a fact that is exploited in a few places,
|
388 |
|
|
* but this doesn't distinguish markers from the base-level
|
389 |
|
|
* header node (head.node), which also has a null key.
|
390 |
|
|
*/
|
391 |
|
|
Node(Node<K,V> next) {
|
392 |
|
|
this.key = null;
|
393 |
|
|
this.value = this;
|
394 |
|
|
this.next = next;
|
395 |
|
|
}
|
396 |
|
|
|
397 |
|
|
/** Updater for casNext */
|
398 |
|
|
static final AtomicReferenceFieldUpdater<Node, Node>
|
399 |
|
|
nextUpdater = AtomicReferenceFieldUpdater.newUpdater
|
400 |
|
|
(Node.class, Node.class, "next");
|
401 |
|
|
|
402 |
|
|
/** Updater for casValue */
|
403 |
|
|
static final AtomicReferenceFieldUpdater<Node, Object>
|
404 |
|
|
valueUpdater = AtomicReferenceFieldUpdater.newUpdater
|
405 |
|
|
(Node.class, Object.class, "value");
|
406 |
|
|
|
407 |
|
|
/**
|
408 |
|
|
* compareAndSet value field
|
409 |
|
|
*/
|
410 |
|
|
boolean casValue(Object cmp, Object val) {
|
411 |
|
|
return valueUpdater.compareAndSet(this, cmp, val);
|
412 |
|
|
}
|
413 |
|
|
|
414 |
|
|
/**
|
415 |
|
|
* compareAndSet next field
|
416 |
|
|
*/
|
417 |
|
|
boolean casNext(Node<K,V> cmp, Node<K,V> val) {
|
418 |
|
|
return nextUpdater.compareAndSet(this, cmp, val);
|
419 |
|
|
}
|
420 |
|
|
|
421 |
|
|
/**
|
422 |
|
|
* Returns true if this node is a marker. This method isn't
|
423 |
|
|
* actually called in any current code checking for markers
|
424 |
|
|
* because callers will have already read value field and need
|
425 |
|
|
* to use that read (not another done here) and so directly
|
426 |
|
|
* test if value points to node.
|
427 |
|
|
* @param n a possibly null reference to a node
|
428 |
|
|
* @return true if this node is a marker node
|
429 |
|
|
*/
|
430 |
|
|
boolean isMarker() {
|
431 |
|
|
return value == this;
|
432 |
|
|
}
|
433 |
|
|
|
434 |
|
|
/**
|
435 |
|
|
* Returns true if this node is the header of base-level list.
|
436 |
|
|
* @return true if this node is header node
|
437 |
|
|
*/
|
438 |
|
|
boolean isBaseHeader() {
|
439 |
|
|
return value == BASE_HEADER;
|
440 |
|
|
}
|
441 |
|
|
|
442 |
|
|
/**
|
443 |
|
|
* Tries to append a deletion marker to this node.
|
444 |
|
|
* @param f the assumed current successor of this node
|
445 |
|
|
* @return true if successful
|
446 |
|
|
*/
|
447 |
|
|
boolean appendMarker(Node<K,V> f) {
|
448 |
|
|
return casNext(f, new Node<K,V>(f));
|
449 |
|
|
}
|
450 |
|
|
|
451 |
|
|
/**
|
452 |
|
|
* Helps out a deletion by appending marker or unlinking from
|
453 |
|
|
* predecessor. This is called during traversals when value
|
454 |
|
|
* field seen to be null.
|
455 |
|
|
* @param b predecessor
|
456 |
|
|
* @param f successor
|
457 |
|
|
*/
|
458 |
|
|
void helpDelete(Node<K,V> b, Node<K,V> f) {
|
459 |
|
|
/*
|
460 |
|
|
* Rechecking links and then doing only one of the
|
461 |
|
|
* help-out stages per call tends to minimize CAS
|
462 |
|
|
* interference among helping threads.
|
463 |
|
|
*/
|
464 |
|
|
if (f == next && this == b.next) {
|
465 |
|
|
if (f == null || f.value != f) // not already marked
|
466 |
|
|
appendMarker(f);
|
467 |
|
|
else
|
468 |
|
|
b.casNext(this, f.next);
|
469 |
|
|
}
|
470 |
|
|
}
|
471 |
|
|
|
472 |
|
|
/**
|
473 |
|
|
* Returns value if this node contains a valid key-value pair,
|
474 |
|
|
* else null.
|
475 |
|
|
* @return this node's value if it isn't a marker or header or
|
476 |
|
|
* is deleted, else null.
|
477 |
|
|
*/
|
478 |
|
|
V getValidValue() {
|
479 |
|
|
Object v = value;
|
480 |
|
|
if (v == this || v == BASE_HEADER)
|
481 |
|
|
return null;
|
482 |
|
|
return (V)v;
|
483 |
|
|
}
|
484 |
|
|
|
485 |
|
|
/**
|
486 |
|
|
* Creates and returns a new SimpleImmutableEntry holding current
|
487 |
|
|
* mapping if this node holds a valid value, else null.
|
488 |
|
|
* @return new entry or null
|
489 |
|
|
*/
|
490 |
|
|
AbstractMap.SimpleImmutableEntry<K,V> createSnapshot() {
|
491 |
|
|
V v = getValidValue();
|
492 |
|
|
if (v == null)
|
493 |
|
|
return null;
|
494 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(key, v);
|
495 |
|
|
}
|
496 |
|
|
}
|
497 |
|
|
|
498 |
|
|
/* ---------------- Indexing -------------- */
|
499 |
|
|
|
500 |
|
|
/**
|
501 |
|
|
* Index nodes represent the levels of the skip list. Note that
|
502 |
|
|
* even though both Nodes and Indexes have forward-pointing
|
503 |
|
|
* fields, they have different types and are handled in different
|
504 |
|
|
* ways, that can't nicely be captured by placing field in a
|
505 |
|
|
* shared abstract class.
|
506 |
|
|
*/
|
507 |
|
|
static class Index<K,V> {
|
508 |
|
|
final Node<K,V> node;
|
509 |
|
|
final Index<K,V> down;
|
510 |
|
|
volatile Index<K,V> right;
|
511 |
|
|
|
512 |
|
|
/**
|
513 |
|
|
* Creates index node with given values.
|
514 |
|
|
*/
|
515 |
|
|
Index(Node<K,V> node, Index<K,V> down, Index<K,V> right) {
|
516 |
|
|
this.node = node;
|
517 |
|
|
this.down = down;
|
518 |
|
|
this.right = right;
|
519 |
|
|
}
|
520 |
|
|
|
521 |
|
|
/** Updater for casRight */
|
522 |
|
|
static final AtomicReferenceFieldUpdater<Index, Index>
|
523 |
|
|
rightUpdater = AtomicReferenceFieldUpdater.newUpdater
|
524 |
|
|
(Index.class, Index.class, "right");
|
525 |
|
|
|
526 |
|
|
/**
|
527 |
|
|
* compareAndSet right field
|
528 |
|
|
*/
|
529 |
|
|
final boolean casRight(Index<K,V> cmp, Index<K,V> val) {
|
530 |
|
|
return rightUpdater.compareAndSet(this, cmp, val);
|
531 |
|
|
}
|
532 |
|
|
|
533 |
|
|
/**
|
534 |
|
|
* Returns true if the node this indexes has been deleted.
|
535 |
|
|
* @return true if indexed node is known to be deleted
|
536 |
|
|
*/
|
537 |
|
|
final boolean indexesDeletedNode() {
|
538 |
|
|
return node.value == null;
|
539 |
|
|
}
|
540 |
|
|
|
541 |
|
|
/**
|
542 |
|
|
* Tries to CAS newSucc as successor. To minimize races with
|
543 |
|
|
* unlink that may lose this index node, if the node being
|
544 |
|
|
* indexed is known to be deleted, it doesn't try to link in.
|
545 |
|
|
* @param succ the expected current successor
|
546 |
|
|
* @param newSucc the new successor
|
547 |
|
|
* @return true if successful
|
548 |
|
|
*/
|
549 |
|
|
final boolean link(Index<K,V> succ, Index<K,V> newSucc) {
|
550 |
|
|
Node<K,V> n = node;
|
551 |
|
|
newSucc.right = succ;
|
552 |
|
|
return n.value != null && casRight(succ, newSucc);
|
553 |
|
|
}
|
554 |
|
|
|
555 |
|
|
/**
|
556 |
|
|
* Tries to CAS right field to skip over apparent successor
|
557 |
|
|
* succ. Fails (forcing a retraversal by caller) if this node
|
558 |
|
|
* is known to be deleted.
|
559 |
|
|
* @param succ the expected current successor
|
560 |
|
|
* @return true if successful
|
561 |
|
|
*/
|
562 |
|
|
final boolean unlink(Index<K,V> succ) {
|
563 |
|
|
return !indexesDeletedNode() && casRight(succ, succ.right);
|
564 |
|
|
}
|
565 |
|
|
}
|
566 |
|
|
|
567 |
|
|
/* ---------------- Head nodes -------------- */
|
568 |
|
|
|
569 |
|
|
/**
|
570 |
|
|
* Nodes heading each level keep track of their level.
|
571 |
|
|
*/
|
572 |
|
|
static final class HeadIndex<K,V> extends Index<K,V> {
|
573 |
|
|
final int level;
|
574 |
|
|
HeadIndex(Node<K,V> node, Index<K,V> down, Index<K,V> right, int level) {
|
575 |
|
|
super(node, down, right);
|
576 |
|
|
this.level = level;
|
577 |
|
|
}
|
578 |
|
|
}
|
579 |
|
|
|
580 |
|
|
/* ---------------- Comparison utilities -------------- */
|
581 |
|
|
|
582 |
|
|
/**
|
583 |
|
|
* Represents a key with a comparator as a Comparable.
|
584 |
|
|
*
|
585 |
|
|
* Because most sorted collections seem to use natural ordering on
|
586 |
|
|
* Comparables (Strings, Integers, etc), most internal methods are
|
587 |
|
|
* geared to use them. This is generally faster than checking
|
588 |
|
|
* per-comparison whether to use comparator or comparable because
|
589 |
|
|
* it doesn't require a (Comparable) cast for each comparison.
|
590 |
|
|
* (Optimizers can only sometimes remove such redundant checks
|
591 |
|
|
* themselves.) When Comparators are used,
|
592 |
|
|
* ComparableUsingComparators are created so that they act in the
|
593 |
|
|
* same way as natural orderings. This penalizes use of
|
594 |
|
|
* Comparators vs Comparables, which seems like the right
|
595 |
|
|
* tradeoff.
|
596 |
|
|
*/
|
597 |
|
|
static final class ComparableUsingComparator<K> implements Comparable<K> {
|
598 |
|
|
final K actualKey;
|
599 |
|
|
final Comparator<? super K> cmp;
|
600 |
|
|
ComparableUsingComparator(K key, Comparator<? super K> cmp) {
|
601 |
|
|
this.actualKey = key;
|
602 |
|
|
this.cmp = cmp;
|
603 |
|
|
}
|
604 |
|
|
public int compareTo(K k2) {
|
605 |
|
|
return cmp.compare(actualKey, k2);
|
606 |
|
|
}
|
607 |
|
|
}
|
608 |
|
|
|
609 |
|
|
/**
|
610 |
|
|
* If using comparator, return a ComparableUsingComparator, else
|
611 |
|
|
* cast key as Comparable, which may cause ClassCastException,
|
612 |
|
|
* which is propagated back to caller.
|
613 |
|
|
*/
|
614 |
|
|
private Comparable<? super K> comparable(Object key) throws ClassCastException {
|
615 |
|
|
if (key == null)
|
616 |
|
|
throw new NullPointerException();
|
617 |
|
|
if (comparator != null)
|
618 |
|
|
return new ComparableUsingComparator<K>((K)key, comparator);
|
619 |
|
|
else
|
620 |
|
|
return (Comparable<? super K>)key;
|
621 |
|
|
}
|
622 |
|
|
|
623 |
|
|
/**
|
624 |
|
|
* Compares using comparator or natural ordering. Used when the
|
625 |
|
|
* ComparableUsingComparator approach doesn't apply.
|
626 |
|
|
*/
|
627 |
|
|
int compare(K k1, K k2) throws ClassCastException {
|
628 |
|
|
Comparator<? super K> cmp = comparator;
|
629 |
|
|
if (cmp != null)
|
630 |
|
|
return cmp.compare(k1, k2);
|
631 |
|
|
else
|
632 |
|
|
return ((Comparable<? super K>)k1).compareTo(k2);
|
633 |
|
|
}
|
634 |
|
|
|
635 |
|
|
/**
|
636 |
|
|
* Returns true if given key greater than or equal to least and
|
637 |
|
|
* strictly less than fence, bypassing either test if least or
|
638 |
|
|
* fence are null. Needed mainly in submap operations.
|
639 |
|
|
*/
|
640 |
|
|
boolean inHalfOpenRange(K key, K least, K fence) {
|
641 |
|
|
if (key == null)
|
642 |
|
|
throw new NullPointerException();
|
643 |
|
|
return ((least == null || compare(key, least) >= 0) &&
|
644 |
|
|
(fence == null || compare(key, fence) < 0));
|
645 |
|
|
}
|
646 |
|
|
|
647 |
|
|
/**
|
648 |
|
|
* Returns true if given key greater than or equal to least and less
|
649 |
|
|
* or equal to fence. Needed mainly in submap operations.
|
650 |
|
|
*/
|
651 |
|
|
boolean inOpenRange(K key, K least, K fence) {
|
652 |
|
|
if (key == null)
|
653 |
|
|
throw new NullPointerException();
|
654 |
|
|
return ((least == null || compare(key, least) >= 0) &&
|
655 |
|
|
(fence == null || compare(key, fence) <= 0));
|
656 |
|
|
}
|
657 |
|
|
|
658 |
|
|
/* ---------------- Traversal -------------- */
|
659 |
|
|
|
660 |
|
|
/**
|
661 |
|
|
* Returns a base-level node with key strictly less than given key,
|
662 |
|
|
* or the base-level header if there is no such node. Also
|
663 |
|
|
* unlinks indexes to deleted nodes found along the way. Callers
|
664 |
|
|
* rely on this side-effect of clearing indices to deleted nodes.
|
665 |
|
|
* @param key the key
|
666 |
|
|
* @return a predecessor of key
|
667 |
|
|
*/
|
668 |
|
|
private Node<K,V> findPredecessor(Comparable<? super K> key) {
|
669 |
|
|
if (key == null)
|
670 |
|
|
throw new NullPointerException(); // don't postpone errors
|
671 |
|
|
for (;;) {
|
672 |
|
|
Index<K,V> q = head;
|
673 |
|
|
Index<K,V> r = q.right;
|
674 |
|
|
for (;;) {
|
675 |
|
|
if (r != null) {
|
676 |
|
|
Node<K,V> n = r.node;
|
677 |
|
|
K k = n.key;
|
678 |
|
|
if (n.value == null) {
|
679 |
|
|
if (!q.unlink(r))
|
680 |
|
|
break; // restart
|
681 |
|
|
r = q.right; // reread r
|
682 |
|
|
continue;
|
683 |
|
|
}
|
684 |
|
|
if (key.compareTo(k) > 0) {
|
685 |
|
|
q = r;
|
686 |
|
|
r = r.right;
|
687 |
|
|
continue;
|
688 |
|
|
}
|
689 |
|
|
}
|
690 |
|
|
Index<K,V> d = q.down;
|
691 |
|
|
if (d != null) {
|
692 |
|
|
q = d;
|
693 |
|
|
r = d.right;
|
694 |
|
|
} else
|
695 |
|
|
return q.node;
|
696 |
|
|
}
|
697 |
|
|
}
|
698 |
|
|
}
|
699 |
|
|
|
700 |
|
|
/**
|
701 |
|
|
* Returns node holding key or null if no such, clearing out any
|
702 |
|
|
* deleted nodes seen along the way. Repeatedly traverses at
|
703 |
|
|
* base-level looking for key starting at predecessor returned
|
704 |
|
|
* from findPredecessor, processing base-level deletions as
|
705 |
|
|
* encountered. Some callers rely on this side-effect of clearing
|
706 |
|
|
* deleted nodes.
|
707 |
|
|
*
|
708 |
|
|
* Restarts occur, at traversal step centered on node n, if:
|
709 |
|
|
*
|
710 |
|
|
* (1) After reading n's next field, n is no longer assumed
|
711 |
|
|
* predecessor b's current successor, which means that
|
712 |
|
|
* we don't have a consistent 3-node snapshot and so cannot
|
713 |
|
|
* unlink any subsequent deleted nodes encountered.
|
714 |
|
|
*
|
715 |
|
|
* (2) n's value field is null, indicating n is deleted, in
|
716 |
|
|
* which case we help out an ongoing structural deletion
|
717 |
|
|
* before retrying. Even though there are cases where such
|
718 |
|
|
* unlinking doesn't require restart, they aren't sorted out
|
719 |
|
|
* here because doing so would not usually outweigh cost of
|
720 |
|
|
* restarting.
|
721 |
|
|
*
|
722 |
|
|
* (3) n is a marker or n's predecessor's value field is null,
|
723 |
|
|
* indicating (among other possibilities) that
|
724 |
|
|
* findPredecessor returned a deleted node. We can't unlink
|
725 |
|
|
* the node because we don't know its predecessor, so rely
|
726 |
|
|
* on another call to findPredecessor to notice and return
|
727 |
|
|
* some earlier predecessor, which it will do. This check is
|
728 |
|
|
* only strictly needed at beginning of loop, (and the
|
729 |
|
|
* b.value check isn't strictly needed at all) but is done
|
730 |
|
|
* each iteration to help avoid contention with other
|
731 |
|
|
* threads by callers that will fail to be able to change
|
732 |
|
|
* links, and so will retry anyway.
|
733 |
|
|
*
|
734 |
|
|
* The traversal loops in doPut, doRemove, and findNear all
|
735 |
|
|
* include the same three kinds of checks. And specialized
|
736 |
|
|
* versions appear in findFirst, and findLast and their
|
737 |
|
|
* variants. They can't easily share code because each uses the
|
738 |
|
|
* reads of fields held in locals occurring in the orders they
|
739 |
|
|
* were performed.
|
740 |
|
|
*
|
741 |
|
|
* @param key the key
|
742 |
|
|
* @return node holding key, or null if no such
|
743 |
|
|
*/
|
744 |
|
|
private Node<K,V> findNode(Comparable<? super K> key) {
|
745 |
|
|
for (;;) {
|
746 |
|
|
Node<K,V> b = findPredecessor(key);
|
747 |
|
|
Node<K,V> n = b.next;
|
748 |
|
|
for (;;) {
|
749 |
|
|
if (n == null)
|
750 |
|
|
return null;
|
751 |
|
|
Node<K,V> f = n.next;
|
752 |
|
|
if (n != b.next) // inconsistent read
|
753 |
|
|
break;
|
754 |
|
|
Object v = n.value;
|
755 |
|
|
if (v == null) { // n is deleted
|
756 |
|
|
n.helpDelete(b, f);
|
757 |
|
|
break;
|
758 |
|
|
}
|
759 |
|
|
if (v == n || b.value == null) // b is deleted
|
760 |
|
|
break;
|
761 |
|
|
int c = key.compareTo(n.key);
|
762 |
|
|
if (c == 0)
|
763 |
|
|
return n;
|
764 |
|
|
if (c < 0)
|
765 |
|
|
return null;
|
766 |
|
|
b = n;
|
767 |
|
|
n = f;
|
768 |
|
|
}
|
769 |
|
|
}
|
770 |
|
|
}
|
771 |
|
|
|
772 |
|
|
/**
|
773 |
|
|
* Specialized variant of findNode to perform Map.get. Does a weak
|
774 |
|
|
* traversal, not bothering to fix any deleted index nodes,
|
775 |
|
|
* returning early if it happens to see key in index, and passing
|
776 |
|
|
* over any deleted base nodes, falling back to getUsingFindNode
|
777 |
|
|
* only if it would otherwise return value from an ongoing
|
778 |
|
|
* deletion. Also uses "bound" to eliminate need for some
|
779 |
|
|
* comparisons (see Pugh Cookbook). Also folds uses of null checks
|
780 |
|
|
* and node-skipping because markers have null keys.
|
781 |
|
|
* @param okey the key
|
782 |
|
|
* @return the value, or null if absent
|
783 |
|
|
*/
|
784 |
|
|
private V doGet(Object okey) {
|
785 |
|
|
Comparable<? super K> key = comparable(okey);
|
786 |
|
|
Node<K,V> bound = null;
|
787 |
|
|
Index<K,V> q = head;
|
788 |
|
|
Index<K,V> r = q.right;
|
789 |
|
|
Node<K,V> n;
|
790 |
|
|
K k;
|
791 |
|
|
int c;
|
792 |
|
|
for (;;) {
|
793 |
|
|
Index<K,V> d;
|
794 |
|
|
// Traverse rights
|
795 |
|
|
if (r != null && (n = r.node) != bound && (k = n.key) != null) {
|
796 |
|
|
if ((c = key.compareTo(k)) > 0) {
|
797 |
|
|
q = r;
|
798 |
|
|
r = r.right;
|
799 |
|
|
continue;
|
800 |
|
|
} else if (c == 0) {
|
801 |
|
|
Object v = n.value;
|
802 |
|
|
return (v != null)? (V)v : getUsingFindNode(key);
|
803 |
|
|
} else
|
804 |
|
|
bound = n;
|
805 |
|
|
}
|
806 |
|
|
|
807 |
|
|
// Traverse down
|
808 |
|
|
if ((d = q.down) != null) {
|
809 |
|
|
q = d;
|
810 |
|
|
r = d.right;
|
811 |
|
|
} else
|
812 |
|
|
break;
|
813 |
|
|
}
|
814 |
|
|
|
815 |
|
|
// Traverse nexts
|
816 |
|
|
for (n = q.node.next; n != null; n = n.next) {
|
817 |
|
|
if ((k = n.key) != null) {
|
818 |
|
|
if ((c = key.compareTo(k)) == 0) {
|
819 |
|
|
Object v = n.value;
|
820 |
|
|
return (v != null)? (V)v : getUsingFindNode(key);
|
821 |
|
|
} else if (c < 0)
|
822 |
|
|
break;
|
823 |
|
|
}
|
824 |
|
|
}
|
825 |
|
|
return null;
|
826 |
|
|
}
|
827 |
|
|
|
828 |
|
|
/**
|
829 |
|
|
* Performs map.get via findNode. Used as a backup if doGet
|
830 |
|
|
* encounters an in-progress deletion.
|
831 |
|
|
* @param key the key
|
832 |
|
|
* @return the value, or null if absent
|
833 |
|
|
*/
|
834 |
|
|
private V getUsingFindNode(Comparable<? super K> key) {
|
835 |
|
|
/*
|
836 |
|
|
* Loop needed here and elsewhere in case value field goes
|
837 |
|
|
* null just as it is about to be returned, in which case we
|
838 |
|
|
* lost a race with a deletion, so must retry.
|
839 |
|
|
*/
|
840 |
|
|
for (;;) {
|
841 |
|
|
Node<K,V> n = findNode(key);
|
842 |
|
|
if (n == null)
|
843 |
|
|
return null;
|
844 |
|
|
Object v = n.value;
|
845 |
|
|
if (v != null)
|
846 |
|
|
return (V)v;
|
847 |
|
|
}
|
848 |
|
|
}
|
849 |
|
|
|
850 |
|
|
/* ---------------- Insertion -------------- */
|
851 |
|
|
|
852 |
|
|
/**
|
853 |
|
|
* Main insertion method. Adds element if not present, or
|
854 |
|
|
* replaces value if present and onlyIfAbsent is false.
|
855 |
|
|
* @param kkey the key
|
856 |
|
|
* @param value the value that must be associated with key
|
857 |
|
|
* @param onlyIfAbsent if should not insert if already present
|
858 |
|
|
* @return the old value, or null if newly inserted
|
859 |
|
|
*/
|
860 |
|
|
private V doPut(K kkey, V value, boolean onlyIfAbsent) {
|
861 |
|
|
Comparable<? super K> key = comparable(kkey);
|
862 |
|
|
for (;;) {
|
863 |
|
|
Node<K,V> b = findPredecessor(key);
|
864 |
|
|
Node<K,V> n = b.next;
|
865 |
|
|
for (;;) {
|
866 |
|
|
if (n != null) {
|
867 |
|
|
Node<K,V> f = n.next;
|
868 |
|
|
if (n != b.next) // inconsistent read
|
869 |
|
|
break;
|
870 |
|
|
Object v = n.value;
|
871 |
|
|
if (v == null) { // n is deleted
|
872 |
|
|
n.helpDelete(b, f);
|
873 |
|
|
break;
|
874 |
|
|
}
|
875 |
|
|
if (v == n || b.value == null) // b is deleted
|
876 |
|
|
break;
|
877 |
|
|
int c = key.compareTo(n.key);
|
878 |
|
|
if (c > 0) {
|
879 |
|
|
b = n;
|
880 |
|
|
n = f;
|
881 |
|
|
continue;
|
882 |
|
|
}
|
883 |
|
|
if (c == 0) {
|
884 |
|
|
if (onlyIfAbsent || n.casValue(v, value))
|
885 |
|
|
return (V)v;
|
886 |
|
|
else
|
887 |
|
|
break; // restart if lost race to replace value
|
888 |
|
|
}
|
889 |
|
|
// else c < 0; fall through
|
890 |
|
|
}
|
891 |
|
|
|
892 |
|
|
Node<K,V> z = new Node<K,V>(kkey, value, n);
|
893 |
|
|
if (!b.casNext(n, z))
|
894 |
|
|
break; // restart if lost race to append to b
|
895 |
|
|
int level = randomLevel();
|
896 |
|
|
if (level > 0)
|
897 |
|
|
insertIndex(z, level);
|
898 |
|
|
return null;
|
899 |
|
|
}
|
900 |
|
|
}
|
901 |
|
|
}
|
902 |
|
|
|
903 |
|
|
/**
|
904 |
|
|
* Returns a random level for inserting a new node.
|
905 |
|
|
* Hardwired to k=1, p=0.5, max 31 (see above and
|
906 |
|
|
* Pugh's "Skip List Cookbook", sec 3.4).
|
907 |
|
|
*
|
908 |
|
|
* This uses the simplest of the generators described in George
|
909 |
|
|
* Marsaglia's "Xorshift RNGs" paper. This is not a high-quality
|
910 |
|
|
* generator but is acceptable here.
|
911 |
|
|
*/
|
912 |
|
|
private int randomLevel() {
|
913 |
|
|
int x = randomSeed;
|
914 |
|
|
x ^= x << 13;
|
915 |
|
|
x ^= x >>> 17;
|
916 |
|
|
randomSeed = x ^= x << 5;
|
917 |
|
|
if ((x & 0x8001) != 0) // test highest and lowest bits
|
918 |
|
|
return 0;
|
919 |
|
|
int level = 1;
|
920 |
|
|
while (((x >>>= 1) & 1) != 0) ++level;
|
921 |
|
|
return level;
|
922 |
|
|
}
|
923 |
|
|
|
924 |
|
|
/**
|
925 |
|
|
* Creates and adds index nodes for the given node.
|
926 |
|
|
* @param z the node
|
927 |
|
|
* @param level the level of the index
|
928 |
|
|
*/
|
929 |
|
|
private void insertIndex(Node<K,V> z, int level) {
|
930 |
|
|
HeadIndex<K,V> h = head;
|
931 |
|
|
int max = h.level;
|
932 |
|
|
|
933 |
|
|
if (level <= max) {
|
934 |
|
|
Index<K,V> idx = null;
|
935 |
|
|
for (int i = 1; i <= level; ++i)
|
936 |
|
|
idx = new Index<K,V>(z, idx, null);
|
937 |
|
|
addIndex(idx, h, level);
|
938 |
|
|
|
939 |
|
|
} else { // Add a new level
|
940 |
|
|
/*
|
941 |
|
|
* To reduce interference by other threads checking for
|
942 |
|
|
* empty levels in tryReduceLevel, new levels are added
|
943 |
|
|
* with initialized right pointers. Which in turn requires
|
944 |
|
|
* keeping levels in an array to access them while
|
945 |
|
|
* creating new head index nodes from the opposite
|
946 |
|
|
* direction.
|
947 |
|
|
*/
|
948 |
|
|
level = max + 1;
|
949 |
|
|
Index<K,V>[] idxs = (Index<K,V>[])new Index[level+1];
|
950 |
|
|
Index<K,V> idx = null;
|
951 |
|
|
for (int i = 1; i <= level; ++i)
|
952 |
|
|
idxs[i] = idx = new Index<K,V>(z, idx, null);
|
953 |
|
|
|
954 |
|
|
HeadIndex<K,V> oldh;
|
955 |
|
|
int k;
|
956 |
|
|
for (;;) {
|
957 |
|
|
oldh = head;
|
958 |
|
|
int oldLevel = oldh.level;
|
959 |
|
|
if (level <= oldLevel) { // lost race to add level
|
960 |
|
|
k = level;
|
961 |
|
|
break;
|
962 |
|
|
}
|
963 |
|
|
HeadIndex<K,V> newh = oldh;
|
964 |
|
|
Node<K,V> oldbase = oldh.node;
|
965 |
|
|
for (int j = oldLevel+1; j <= level; ++j)
|
966 |
|
|
newh = new HeadIndex<K,V>(oldbase, newh, idxs[j], j);
|
967 |
|
|
if (casHead(oldh, newh)) {
|
968 |
|
|
k = oldLevel;
|
969 |
|
|
break;
|
970 |
|
|
}
|
971 |
|
|
}
|
972 |
|
|
addIndex(idxs[k], oldh, k);
|
973 |
|
|
}
|
974 |
|
|
}
|
975 |
|
|
|
976 |
|
|
/**
|
977 |
|
|
* Adds given index nodes from given level down to 1.
|
978 |
|
|
* @param idx the topmost index node being inserted
|
979 |
|
|
* @param h the value of head to use to insert. This must be
|
980 |
|
|
* snapshotted by callers to provide correct insertion level
|
981 |
|
|
* @param indexLevel the level of the index
|
982 |
|
|
*/
|
983 |
|
|
private void addIndex(Index<K,V> idx, HeadIndex<K,V> h, int indexLevel) {
|
984 |
|
|
// Track next level to insert in case of retries
|
985 |
|
|
int insertionLevel = indexLevel;
|
986 |
|
|
Comparable<? super K> key = comparable(idx.node.key);
|
987 |
|
|
if (key == null) throw new NullPointerException();
|
988 |
|
|
|
989 |
|
|
// Similar to findPredecessor, but adding index nodes along
|
990 |
|
|
// path to key.
|
991 |
|
|
for (;;) {
|
992 |
|
|
int j = h.level;
|
993 |
|
|
Index<K,V> q = h;
|
994 |
|
|
Index<K,V> r = q.right;
|
995 |
|
|
Index<K,V> t = idx;
|
996 |
|
|
for (;;) {
|
997 |
|
|
if (r != null) {
|
998 |
|
|
Node<K,V> n = r.node;
|
999 |
|
|
// compare before deletion check avoids needing recheck
|
1000 |
|
|
int c = key.compareTo(n.key);
|
1001 |
|
|
if (n.value == null) {
|
1002 |
|
|
if (!q.unlink(r))
|
1003 |
|
|
break;
|
1004 |
|
|
r = q.right;
|
1005 |
|
|
continue;
|
1006 |
|
|
}
|
1007 |
|
|
if (c > 0) {
|
1008 |
|
|
q = r;
|
1009 |
|
|
r = r.right;
|
1010 |
|
|
continue;
|
1011 |
|
|
}
|
1012 |
|
|
}
|
1013 |
|
|
|
1014 |
|
|
if (j == insertionLevel) {
|
1015 |
|
|
// Don't insert index if node already deleted
|
1016 |
|
|
if (t.indexesDeletedNode()) {
|
1017 |
|
|
findNode(key); // cleans up
|
1018 |
|
|
return;
|
1019 |
|
|
}
|
1020 |
|
|
if (!q.link(r, t))
|
1021 |
|
|
break; // restart
|
1022 |
|
|
if (--insertionLevel == 0) {
|
1023 |
|
|
// need final deletion check before return
|
1024 |
|
|
if (t.indexesDeletedNode())
|
1025 |
|
|
findNode(key);
|
1026 |
|
|
return;
|
1027 |
|
|
}
|
1028 |
|
|
}
|
1029 |
|
|
|
1030 |
|
|
if (--j >= insertionLevel && j < indexLevel)
|
1031 |
|
|
t = t.down;
|
1032 |
|
|
q = q.down;
|
1033 |
|
|
r = q.right;
|
1034 |
|
|
}
|
1035 |
|
|
}
|
1036 |
|
|
}
|
1037 |
|
|
|
1038 |
|
|
/* ---------------- Deletion -------------- */
|
1039 |
|
|
|
1040 |
|
|
/**
|
1041 |
|
|
* Main deletion method. Locates node, nulls value, appends a
|
1042 |
|
|
* deletion marker, unlinks predecessor, removes associated index
|
1043 |
|
|
* nodes, and possibly reduces head index level.
|
1044 |
|
|
*
|
1045 |
|
|
* Index nodes are cleared out simply by calling findPredecessor.
|
1046 |
|
|
* which unlinks indexes to deleted nodes found along path to key,
|
1047 |
|
|
* which will include the indexes to this node. This is done
|
1048 |
|
|
* unconditionally. We can't check beforehand whether there are
|
1049 |
|
|
* index nodes because it might be the case that some or all
|
1050 |
|
|
* indexes hadn't been inserted yet for this node during initial
|
1051 |
|
|
* search for it, and we'd like to ensure lack of garbage
|
1052 |
|
|
* retention, so must call to be sure.
|
1053 |
|
|
*
|
1054 |
|
|
* @param okey the key
|
1055 |
|
|
* @param value if non-null, the value that must be
|
1056 |
|
|
* associated with key
|
1057 |
|
|
* @return the node, or null if not found
|
1058 |
|
|
*/
|
1059 |
|
|
final V doRemove(Object okey, Object value) {
|
1060 |
|
|
Comparable<? super K> key = comparable(okey);
|
1061 |
|
|
for (;;) {
|
1062 |
|
|
Node<K,V> b = findPredecessor(key);
|
1063 |
|
|
Node<K,V> n = b.next;
|
1064 |
|
|
for (;;) {
|
1065 |
|
|
if (n == null)
|
1066 |
|
|
return null;
|
1067 |
|
|
Node<K,V> f = n.next;
|
1068 |
|
|
if (n != b.next) // inconsistent read
|
1069 |
|
|
break;
|
1070 |
|
|
Object v = n.value;
|
1071 |
|
|
if (v == null) { // n is deleted
|
1072 |
|
|
n.helpDelete(b, f);
|
1073 |
|
|
break;
|
1074 |
|
|
}
|
1075 |
|
|
if (v == n || b.value == null) // b is deleted
|
1076 |
|
|
break;
|
1077 |
|
|
int c = key.compareTo(n.key);
|
1078 |
|
|
if (c < 0)
|
1079 |
|
|
return null;
|
1080 |
|
|
if (c > 0) {
|
1081 |
|
|
b = n;
|
1082 |
|
|
n = f;
|
1083 |
|
|
continue;
|
1084 |
|
|
}
|
1085 |
|
|
if (value != null && !value.equals(v))
|
1086 |
|
|
return null;
|
1087 |
|
|
if (!n.casValue(v, null))
|
1088 |
|
|
break;
|
1089 |
|
|
if (!n.appendMarker(f) || !b.casNext(n, f))
|
1090 |
|
|
findNode(key); // Retry via findNode
|
1091 |
|
|
else {
|
1092 |
|
|
findPredecessor(key); // Clean index
|
1093 |
|
|
if (head.right == null)
|
1094 |
|
|
tryReduceLevel();
|
1095 |
|
|
}
|
1096 |
|
|
return (V)v;
|
1097 |
|
|
}
|
1098 |
|
|
}
|
1099 |
|
|
}
|
1100 |
|
|
|
1101 |
|
|
/**
|
1102 |
|
|
* Possibly reduce head level if it has no nodes. This method can
|
1103 |
|
|
* (rarely) make mistakes, in which case levels can disappear even
|
1104 |
|
|
* though they are about to contain index nodes. This impacts
|
1105 |
|
|
* performance, not correctness. To minimize mistakes as well as
|
1106 |
|
|
* to reduce hysteresis, the level is reduced by one only if the
|
1107 |
|
|
* topmost three levels look empty. Also, if the removed level
|
1108 |
|
|
* looks non-empty after CAS, we try to change it back quick
|
1109 |
|
|
* before anyone notices our mistake! (This trick works pretty
|
1110 |
|
|
* well because this method will practically never make mistakes
|
1111 |
|
|
* unless current thread stalls immediately before first CAS, in
|
1112 |
|
|
* which case it is very unlikely to stall again immediately
|
1113 |
|
|
* afterwards, so will recover.)
|
1114 |
|
|
*
|
1115 |
|
|
* We put up with all this rather than just let levels grow
|
1116 |
|
|
* because otherwise, even a small map that has undergone a large
|
1117 |
|
|
* number of insertions and removals will have a lot of levels,
|
1118 |
|
|
* slowing down access more than would an occasional unwanted
|
1119 |
|
|
* reduction.
|
1120 |
|
|
*/
|
1121 |
|
|
private void tryReduceLevel() {
|
1122 |
|
|
HeadIndex<K,V> h = head;
|
1123 |
|
|
HeadIndex<K,V> d;
|
1124 |
|
|
HeadIndex<K,V> e;
|
1125 |
|
|
if (h.level > 3 &&
|
1126 |
|
|
(d = (HeadIndex<K,V>)h.down) != null &&
|
1127 |
|
|
(e = (HeadIndex<K,V>)d.down) != null &&
|
1128 |
|
|
e.right == null &&
|
1129 |
|
|
d.right == null &&
|
1130 |
|
|
h.right == null &&
|
1131 |
|
|
casHead(h, d) && // try to set
|
1132 |
|
|
h.right != null) // recheck
|
1133 |
|
|
casHead(d, h); // try to backout
|
1134 |
|
|
}
|
1135 |
|
|
|
1136 |
|
|
/* ---------------- Finding and removing first element -------------- */
|
1137 |
|
|
|
1138 |
|
|
/**
|
1139 |
|
|
* Specialized variant of findNode to get first valid node.
|
1140 |
|
|
* @return first node or null if empty
|
1141 |
|
|
*/
|
1142 |
|
|
Node<K,V> findFirst() {
|
1143 |
|
|
for (;;) {
|
1144 |
|
|
Node<K,V> b = head.node;
|
1145 |
|
|
Node<K,V> n = b.next;
|
1146 |
|
|
if (n == null)
|
1147 |
|
|
return null;
|
1148 |
|
|
if (n.value != null)
|
1149 |
|
|
return n;
|
1150 |
|
|
n.helpDelete(b, n.next);
|
1151 |
|
|
}
|
1152 |
|
|
}
|
1153 |
|
|
|
1154 |
|
|
/**
|
1155 |
|
|
* Removes first entry; returns its snapshot.
|
1156 |
|
|
* @return null if empty, else snapshot of first entry
|
1157 |
|
|
*/
|
1158 |
|
|
Map.Entry<K,V> doRemoveFirstEntry() {
|
1159 |
|
|
for (;;) {
|
1160 |
|
|
Node<K,V> b = head.node;
|
1161 |
|
|
Node<K,V> n = b.next;
|
1162 |
|
|
if (n == null)
|
1163 |
|
|
return null;
|
1164 |
|
|
Node<K,V> f = n.next;
|
1165 |
|
|
if (n != b.next)
|
1166 |
|
|
continue;
|
1167 |
|
|
Object v = n.value;
|
1168 |
|
|
if (v == null) {
|
1169 |
|
|
n.helpDelete(b, f);
|
1170 |
|
|
continue;
|
1171 |
|
|
}
|
1172 |
|
|
if (!n.casValue(v, null))
|
1173 |
|
|
continue;
|
1174 |
|
|
if (!n.appendMarker(f) || !b.casNext(n, f))
|
1175 |
|
|
findFirst(); // retry
|
1176 |
|
|
clearIndexToFirst();
|
1177 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(n.key, (V)v);
|
1178 |
|
|
}
|
1179 |
|
|
}
|
1180 |
|
|
|
1181 |
|
|
/**
|
1182 |
|
|
* Clears out index nodes associated with deleted first entry.
|
1183 |
|
|
*/
|
1184 |
|
|
private void clearIndexToFirst() {
|
1185 |
|
|
for (;;) {
|
1186 |
|
|
Index<K,V> q = head;
|
1187 |
|
|
for (;;) {
|
1188 |
|
|
Index<K,V> r = q.right;
|
1189 |
|
|
if (r != null && r.indexesDeletedNode() && !q.unlink(r))
|
1190 |
|
|
break;
|
1191 |
|
|
if ((q = q.down) == null) {
|
1192 |
|
|
if (head.right == null)
|
1193 |
|
|
tryReduceLevel();
|
1194 |
|
|
return;
|
1195 |
|
|
}
|
1196 |
|
|
}
|
1197 |
|
|
}
|
1198 |
|
|
}
|
1199 |
|
|
|
1200 |
|
|
|
1201 |
|
|
/* ---------------- Finding and removing last element -------------- */
|
1202 |
|
|
|
1203 |
|
|
/**
|
1204 |
|
|
* Specialized version of find to get last valid node.
|
1205 |
|
|
* @return last node or null if empty
|
1206 |
|
|
*/
|
1207 |
|
|
Node<K,V> findLast() {
|
1208 |
|
|
/*
|
1209 |
|
|
* findPredecessor can't be used to traverse index level
|
1210 |
|
|
* because this doesn't use comparisons. So traversals of
|
1211 |
|
|
* both levels are folded together.
|
1212 |
|
|
*/
|
1213 |
|
|
Index<K,V> q = head;
|
1214 |
|
|
for (;;) {
|
1215 |
|
|
Index<K,V> d, r;
|
1216 |
|
|
if ((r = q.right) != null) {
|
1217 |
|
|
if (r.indexesDeletedNode()) {
|
1218 |
|
|
q.unlink(r);
|
1219 |
|
|
q = head; // restart
|
1220 |
|
|
}
|
1221 |
|
|
else
|
1222 |
|
|
q = r;
|
1223 |
|
|
} else if ((d = q.down) != null) {
|
1224 |
|
|
q = d;
|
1225 |
|
|
} else {
|
1226 |
|
|
Node<K,V> b = q.node;
|
1227 |
|
|
Node<K,V> n = b.next;
|
1228 |
|
|
for (;;) {
|
1229 |
|
|
if (n == null)
|
1230 |
|
|
return (b.isBaseHeader())? null : b;
|
1231 |
|
|
Node<K,V> f = n.next; // inconsistent read
|
1232 |
|
|
if (n != b.next)
|
1233 |
|
|
break;
|
1234 |
|
|
Object v = n.value;
|
1235 |
|
|
if (v == null) { // n is deleted
|
1236 |
|
|
n.helpDelete(b, f);
|
1237 |
|
|
break;
|
1238 |
|
|
}
|
1239 |
|
|
if (v == n || b.value == null) // b is deleted
|
1240 |
|
|
break;
|
1241 |
|
|
b = n;
|
1242 |
|
|
n = f;
|
1243 |
|
|
}
|
1244 |
|
|
q = head; // restart
|
1245 |
|
|
}
|
1246 |
|
|
}
|
1247 |
|
|
}
|
1248 |
|
|
|
1249 |
|
|
/**
|
1250 |
|
|
* Specialized variant of findPredecessor to get predecessor of last
|
1251 |
|
|
* valid node. Needed when removing the last entry. It is possible
|
1252 |
|
|
* that all successors of returned node will have been deleted upon
|
1253 |
|
|
* return, in which case this method can be retried.
|
1254 |
|
|
* @return likely predecessor of last node
|
1255 |
|
|
*/
|
1256 |
|
|
private Node<K,V> findPredecessorOfLast() {
|
1257 |
|
|
for (;;) {
|
1258 |
|
|
Index<K,V> q = head;
|
1259 |
|
|
for (;;) {
|
1260 |
|
|
Index<K,V> d, r;
|
1261 |
|
|
if ((r = q.right) != null) {
|
1262 |
|
|
if (r.indexesDeletedNode()) {
|
1263 |
|
|
q.unlink(r);
|
1264 |
|
|
break; // must restart
|
1265 |
|
|
}
|
1266 |
|
|
// proceed as far across as possible without overshooting
|
1267 |
|
|
if (r.node.next != null) {
|
1268 |
|
|
q = r;
|
1269 |
|
|
continue;
|
1270 |
|
|
}
|
1271 |
|
|
}
|
1272 |
|
|
if ((d = q.down) != null)
|
1273 |
|
|
q = d;
|
1274 |
|
|
else
|
1275 |
|
|
return q.node;
|
1276 |
|
|
}
|
1277 |
|
|
}
|
1278 |
|
|
}
|
1279 |
|
|
|
1280 |
|
|
/**
|
1281 |
|
|
* Removes last entry; returns its snapshot.
|
1282 |
|
|
* Specialized variant of doRemove.
|
1283 |
|
|
* @return null if empty, else snapshot of last entry
|
1284 |
|
|
*/
|
1285 |
|
|
Map.Entry<K,V> doRemoveLastEntry() {
|
1286 |
|
|
for (;;) {
|
1287 |
|
|
Node<K,V> b = findPredecessorOfLast();
|
1288 |
|
|
Node<K,V> n = b.next;
|
1289 |
|
|
if (n == null) {
|
1290 |
|
|
if (b.isBaseHeader()) // empty
|
1291 |
|
|
return null;
|
1292 |
|
|
else
|
1293 |
|
|
continue; // all b's successors are deleted; retry
|
1294 |
|
|
}
|
1295 |
|
|
for (;;) {
|
1296 |
|
|
Node<K,V> f = n.next;
|
1297 |
|
|
if (n != b.next) // inconsistent read
|
1298 |
|
|
break;
|
1299 |
|
|
Object v = n.value;
|
1300 |
|
|
if (v == null) { // n is deleted
|
1301 |
|
|
n.helpDelete(b, f);
|
1302 |
|
|
break;
|
1303 |
|
|
}
|
1304 |
|
|
if (v == n || b.value == null) // b is deleted
|
1305 |
|
|
break;
|
1306 |
|
|
if (f != null) {
|
1307 |
|
|
b = n;
|
1308 |
|
|
n = f;
|
1309 |
|
|
continue;
|
1310 |
|
|
}
|
1311 |
|
|
if (!n.casValue(v, null))
|
1312 |
|
|
break;
|
1313 |
|
|
K key = n.key;
|
1314 |
|
|
Comparable<? super K> ck = comparable(key);
|
1315 |
|
|
if (!n.appendMarker(f) || !b.casNext(n, f))
|
1316 |
|
|
findNode(ck); // Retry via findNode
|
1317 |
|
|
else {
|
1318 |
|
|
findPredecessor(ck); // Clean index
|
1319 |
|
|
if (head.right == null)
|
1320 |
|
|
tryReduceLevel();
|
1321 |
|
|
}
|
1322 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(key, (V)v);
|
1323 |
|
|
}
|
1324 |
|
|
}
|
1325 |
|
|
}
|
1326 |
|
|
|
1327 |
|
|
/* ---------------- Relational operations -------------- */
|
1328 |
|
|
|
1329 |
|
|
// Control values OR'ed as arguments to findNear
|
1330 |
|
|
|
1331 |
|
|
private static final int EQ = 1;
|
1332 |
|
|
private static final int LT = 2;
|
1333 |
|
|
private static final int GT = 0; // Actually checked as !LT
|
1334 |
|
|
|
1335 |
|
|
/**
|
1336 |
|
|
* Utility for ceiling, floor, lower, higher methods.
|
1337 |
|
|
* @param kkey the key
|
1338 |
|
|
* @param rel the relation -- OR'ed combination of EQ, LT, GT
|
1339 |
|
|
* @return nearest node fitting relation, or null if no such
|
1340 |
|
|
*/
|
1341 |
|
|
Node<K,V> findNear(K kkey, int rel) {
|
1342 |
|
|
Comparable<? super K> key = comparable(kkey);
|
1343 |
|
|
for (;;) {
|
1344 |
|
|
Node<K,V> b = findPredecessor(key);
|
1345 |
|
|
Node<K,V> n = b.next;
|
1346 |
|
|
for (;;) {
|
1347 |
|
|
if (n == null)
|
1348 |
|
|
return ((rel & LT) == 0 || b.isBaseHeader())? null : b;
|
1349 |
|
|
Node<K,V> f = n.next;
|
1350 |
|
|
if (n != b.next) // inconsistent read
|
1351 |
|
|
break;
|
1352 |
|
|
Object v = n.value;
|
1353 |
|
|
if (v == null) { // n is deleted
|
1354 |
|
|
n.helpDelete(b, f);
|
1355 |
|
|
break;
|
1356 |
|
|
}
|
1357 |
|
|
if (v == n || b.value == null) // b is deleted
|
1358 |
|
|
break;
|
1359 |
|
|
int c = key.compareTo(n.key);
|
1360 |
|
|
if ((c == 0 && (rel & EQ) != 0) ||
|
1361 |
|
|
(c < 0 && (rel & LT) == 0))
|
1362 |
|
|
return n;
|
1363 |
|
|
if ( c <= 0 && (rel & LT) != 0)
|
1364 |
|
|
return (b.isBaseHeader())? null : b;
|
1365 |
|
|
b = n;
|
1366 |
|
|
n = f;
|
1367 |
|
|
}
|
1368 |
|
|
}
|
1369 |
|
|
}
|
1370 |
|
|
|
1371 |
|
|
/**
|
1372 |
|
|
* Returns SimpleImmutableEntry for results of findNear.
|
1373 |
|
|
* @param key the key
|
1374 |
|
|
* @param rel the relation -- OR'ed combination of EQ, LT, GT
|
1375 |
|
|
* @return Entry fitting relation, or null if no such
|
1376 |
|
|
*/
|
1377 |
|
|
AbstractMap.SimpleImmutableEntry<K,V> getNear(K key, int rel) {
|
1378 |
|
|
for (;;) {
|
1379 |
|
|
Node<K,V> n = findNear(key, rel);
|
1380 |
|
|
if (n == null)
|
1381 |
|
|
return null;
|
1382 |
|
|
AbstractMap.SimpleImmutableEntry<K,V> e = n.createSnapshot();
|
1383 |
|
|
if (e != null)
|
1384 |
|
|
return e;
|
1385 |
|
|
}
|
1386 |
|
|
}
|
1387 |
|
|
|
1388 |
|
|
|
1389 |
|
|
/* ---------------- Constructors -------------- */
|
1390 |
|
|
|
1391 |
|
|
/**
|
1392 |
|
|
* Constructs a new, empty map, sorted according to the
|
1393 |
|
|
* {@linkplain Comparable natural ordering} of the keys.
|
1394 |
|
|
*/
|
1395 |
|
|
public ConcurrentSkipListMap() {
|
1396 |
|
|
this.comparator = null;
|
1397 |
|
|
initialize();
|
1398 |
|
|
}
|
1399 |
|
|
|
1400 |
|
|
/**
|
1401 |
|
|
* Constructs a new, empty map, sorted according to the specified
|
1402 |
|
|
* comparator.
|
1403 |
|
|
*
|
1404 |
|
|
* @param comparator the comparator that will be used to order this map.
|
1405 |
|
|
* If <tt>null</tt>, the {@linkplain Comparable natural
|
1406 |
|
|
* ordering} of the keys will be used.
|
1407 |
|
|
*/
|
1408 |
|
|
public ConcurrentSkipListMap(Comparator<? super K> comparator) {
|
1409 |
|
|
this.comparator = comparator;
|
1410 |
|
|
initialize();
|
1411 |
|
|
}
|
1412 |
|
|
|
1413 |
|
|
/**
|
1414 |
|
|
* Constructs a new map containing the same mappings as the given map,
|
1415 |
|
|
* sorted according to the {@linkplain Comparable natural ordering} of
|
1416 |
|
|
* the keys.
|
1417 |
|
|
*
|
1418 |
|
|
* @param m the map whose mappings are to be placed in this map
|
1419 |
|
|
* @throws ClassCastException if the keys in <tt>m</tt> are not
|
1420 |
|
|
* {@link Comparable}, or are not mutually comparable
|
1421 |
|
|
* @throws NullPointerException if the specified map or any of its keys
|
1422 |
|
|
* or values are null
|
1423 |
|
|
*/
|
1424 |
|
|
public ConcurrentSkipListMap(Map<? extends K, ? extends V> m) {
|
1425 |
|
|
this.comparator = null;
|
1426 |
|
|
initialize();
|
1427 |
|
|
putAll(m);
|
1428 |
|
|
}
|
1429 |
|
|
|
1430 |
|
|
/**
|
1431 |
|
|
* Constructs a new map containing the same mappings and using the
|
1432 |
|
|
* same ordering as the specified sorted map.
|
1433 |
|
|
*
|
1434 |
|
|
* @param m the sorted map whose mappings are to be placed in this
|
1435 |
|
|
* map, and whose comparator is to be used to sort this map
|
1436 |
|
|
* @throws NullPointerException if the specified sorted map or any of
|
1437 |
|
|
* its keys or values are null
|
1438 |
|
|
*/
|
1439 |
|
|
public ConcurrentSkipListMap(SortedMap<K, ? extends V> m) {
|
1440 |
|
|
this.comparator = m.comparator();
|
1441 |
|
|
initialize();
|
1442 |
|
|
buildFromSorted(m);
|
1443 |
|
|
}
|
1444 |
|
|
|
1445 |
|
|
/**
|
1446 |
|
|
* Returns a shallow copy of this <tt>ConcurrentSkipListMap</tt>
|
1447 |
|
|
* instance. (The keys and values themselves are not cloned.)
|
1448 |
|
|
*
|
1449 |
|
|
* @return a shallow copy of this map
|
1450 |
|
|
*/
|
1451 |
|
|
public ConcurrentSkipListMap<K,V> clone() {
|
1452 |
|
|
ConcurrentSkipListMap<K,V> clone = null;
|
1453 |
|
|
try {
|
1454 |
|
|
clone = (ConcurrentSkipListMap<K,V>) super.clone();
|
1455 |
|
|
} catch (CloneNotSupportedException e) {
|
1456 |
|
|
throw new InternalError();
|
1457 |
|
|
}
|
1458 |
|
|
|
1459 |
|
|
clone.initialize();
|
1460 |
|
|
clone.buildFromSorted(this);
|
1461 |
|
|
return clone;
|
1462 |
|
|
}
|
1463 |
|
|
|
1464 |
|
|
/**
|
1465 |
|
|
* Streamlined bulk insertion to initialize from elements of
|
1466 |
|
|
* given sorted map. Call only from constructor or clone
|
1467 |
|
|
* method.
|
1468 |
|
|
*/
|
1469 |
|
|
private void buildFromSorted(SortedMap<K, ? extends V> map) {
|
1470 |
|
|
if (map == null)
|
1471 |
|
|
throw new NullPointerException();
|
1472 |
|
|
|
1473 |
|
|
HeadIndex<K,V> h = head;
|
1474 |
|
|
Node<K,V> basepred = h.node;
|
1475 |
|
|
|
1476 |
|
|
// Track the current rightmost node at each level. Uses an
|
1477 |
|
|
// ArrayList to avoid committing to initial or maximum level.
|
1478 |
|
|
ArrayList<Index<K,V>> preds = new ArrayList<Index<K,V>>();
|
1479 |
|
|
|
1480 |
|
|
// initialize
|
1481 |
|
|
for (int i = 0; i <= h.level; ++i)
|
1482 |
|
|
preds.add(null);
|
1483 |
|
|
Index<K,V> q = h;
|
1484 |
|
|
for (int i = h.level; i > 0; --i) {
|
1485 |
|
|
preds.set(i, q);
|
1486 |
|
|
q = q.down;
|
1487 |
|
|
}
|
1488 |
|
|
|
1489 |
|
|
Iterator<? extends Map.Entry<? extends K, ? extends V>> it =
|
1490 |
|
|
map.entrySet().iterator();
|
1491 |
|
|
while (it.hasNext()) {
|
1492 |
|
|
Map.Entry<? extends K, ? extends V> e = it.next();
|
1493 |
|
|
int j = randomLevel();
|
1494 |
|
|
if (j > h.level) j = h.level + 1;
|
1495 |
|
|
K k = e.getKey();
|
1496 |
|
|
V v = e.getValue();
|
1497 |
|
|
if (k == null || v == null)
|
1498 |
|
|
throw new NullPointerException();
|
1499 |
|
|
Node<K,V> z = new Node<K,V>(k, v, null);
|
1500 |
|
|
basepred.next = z;
|
1501 |
|
|
basepred = z;
|
1502 |
|
|
if (j > 0) {
|
1503 |
|
|
Index<K,V> idx = null;
|
1504 |
|
|
for (int i = 1; i <= j; ++i) {
|
1505 |
|
|
idx = new Index<K,V>(z, idx, null);
|
1506 |
|
|
if (i > h.level)
|
1507 |
|
|
h = new HeadIndex<K,V>(h.node, h, idx, i);
|
1508 |
|
|
|
1509 |
|
|
if (i < preds.size()) {
|
1510 |
|
|
preds.get(i).right = idx;
|
1511 |
|
|
preds.set(i, idx);
|
1512 |
|
|
} else
|
1513 |
|
|
preds.add(idx);
|
1514 |
|
|
}
|
1515 |
|
|
}
|
1516 |
|
|
}
|
1517 |
|
|
head = h;
|
1518 |
|
|
}
|
1519 |
|
|
|
1520 |
|
|
/* ---------------- Serialization -------------- */
|
1521 |
|
|
|
1522 |
|
|
/**
|
1523 |
|
|
* Save the state of this map to a stream.
|
1524 |
|
|
*
|
1525 |
|
|
* @serialData The key (Object) and value (Object) for each
|
1526 |
|
|
* key-value mapping represented by the map, followed by
|
1527 |
|
|
* <tt>null</tt>. The key-value mappings are emitted in key-order
|
1528 |
|
|
* (as determined by the Comparator, or by the keys' natural
|
1529 |
|
|
* ordering if no Comparator).
|
1530 |
|
|
*/
|
1531 |
|
|
private void writeObject(java.io.ObjectOutputStream s)
|
1532 |
|
|
throws java.io.IOException {
|
1533 |
|
|
// Write out the Comparator and any hidden stuff
|
1534 |
|
|
s.defaultWriteObject();
|
1535 |
|
|
|
1536 |
|
|
// Write out keys and values (alternating)
|
1537 |
|
|
for (Node<K,V> n = findFirst(); n != null; n = n.next) {
|
1538 |
|
|
V v = n.getValidValue();
|
1539 |
|
|
if (v != null) {
|
1540 |
|
|
s.writeObject(n.key);
|
1541 |
|
|
s.writeObject(v);
|
1542 |
|
|
}
|
1543 |
|
|
}
|
1544 |
|
|
s.writeObject(null);
|
1545 |
|
|
}
|
1546 |
|
|
|
1547 |
|
|
/**
|
1548 |
|
|
* Reconstitute the map from a stream.
|
1549 |
|
|
*/
|
1550 |
|
|
private void readObject(final java.io.ObjectInputStream s)
|
1551 |
|
|
throws java.io.IOException, ClassNotFoundException {
|
1552 |
|
|
// Read in the Comparator and any hidden stuff
|
1553 |
|
|
s.defaultReadObject();
|
1554 |
|
|
// Reset transients
|
1555 |
|
|
initialize();
|
1556 |
|
|
|
1557 |
|
|
/*
|
1558 |
|
|
* This is nearly identical to buildFromSorted, but is
|
1559 |
|
|
* distinct because readObject calls can't be nicely adapted
|
1560 |
|
|
* as the kind of iterator needed by buildFromSorted. (They
|
1561 |
|
|
* can be, but doing so requires type cheats and/or creation
|
1562 |
|
|
* of adaptor classes.) It is simpler to just adapt the code.
|
1563 |
|
|
*/
|
1564 |
|
|
|
1565 |
|
|
HeadIndex<K,V> h = head;
|
1566 |
|
|
Node<K,V> basepred = h.node;
|
1567 |
|
|
ArrayList<Index<K,V>> preds = new ArrayList<Index<K,V>>();
|
1568 |
|
|
for (int i = 0; i <= h.level; ++i)
|
1569 |
|
|
preds.add(null);
|
1570 |
|
|
Index<K,V> q = h;
|
1571 |
|
|
for (int i = h.level; i > 0; --i) {
|
1572 |
|
|
preds.set(i, q);
|
1573 |
|
|
q = q.down;
|
1574 |
|
|
}
|
1575 |
|
|
|
1576 |
|
|
for (;;) {
|
1577 |
|
|
Object k = s.readObject();
|
1578 |
|
|
if (k == null)
|
1579 |
|
|
break;
|
1580 |
|
|
Object v = s.readObject();
|
1581 |
|
|
if (v == null)
|
1582 |
|
|
throw new NullPointerException();
|
1583 |
|
|
K key = (K) k;
|
1584 |
|
|
V val = (V) v;
|
1585 |
|
|
int j = randomLevel();
|
1586 |
|
|
if (j > h.level) j = h.level + 1;
|
1587 |
|
|
Node<K,V> z = new Node<K,V>(key, val, null);
|
1588 |
|
|
basepred.next = z;
|
1589 |
|
|
basepred = z;
|
1590 |
|
|
if (j > 0) {
|
1591 |
|
|
Index<K,V> idx = null;
|
1592 |
|
|
for (int i = 1; i <= j; ++i) {
|
1593 |
|
|
idx = new Index<K,V>(z, idx, null);
|
1594 |
|
|
if (i > h.level)
|
1595 |
|
|
h = new HeadIndex<K,V>(h.node, h, idx, i);
|
1596 |
|
|
|
1597 |
|
|
if (i < preds.size()) {
|
1598 |
|
|
preds.get(i).right = idx;
|
1599 |
|
|
preds.set(i, idx);
|
1600 |
|
|
} else
|
1601 |
|
|
preds.add(idx);
|
1602 |
|
|
}
|
1603 |
|
|
}
|
1604 |
|
|
}
|
1605 |
|
|
head = h;
|
1606 |
|
|
}
|
1607 |
|
|
|
1608 |
|
|
/* ------ Map API methods ------ */
|
1609 |
|
|
|
1610 |
|
|
/**
|
1611 |
|
|
* Returns <tt>true</tt> if this map contains a mapping for the specified
|
1612 |
|
|
* key.
|
1613 |
|
|
*
|
1614 |
|
|
* @param key key whose presence in this map is to be tested
|
1615 |
|
|
* @return <tt>true</tt> if this map contains a mapping for the specified key
|
1616 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1617 |
|
|
* with the keys currently in the map
|
1618 |
|
|
* @throws NullPointerException if the specified key is null
|
1619 |
|
|
*/
|
1620 |
|
|
public boolean containsKey(Object key) {
|
1621 |
|
|
return doGet(key) != null;
|
1622 |
|
|
}
|
1623 |
|
|
|
1624 |
|
|
/**
|
1625 |
|
|
* Returns the value to which the specified key is mapped,
|
1626 |
|
|
* or {@code null} if this map contains no mapping for the key.
|
1627 |
|
|
*
|
1628 |
|
|
* <p>More formally, if this map contains a mapping from a key
|
1629 |
|
|
* {@code k} to a value {@code v} such that {@code key} compares
|
1630 |
|
|
* equal to {@code k} according to the map's ordering, then this
|
1631 |
|
|
* method returns {@code v}; otherwise it returns {@code null}.
|
1632 |
|
|
* (There can be at most one such mapping.)
|
1633 |
|
|
*
|
1634 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1635 |
|
|
* with the keys currently in the map
|
1636 |
|
|
* @throws NullPointerException if the specified key is null
|
1637 |
|
|
*/
|
1638 |
|
|
public V get(Object key) {
|
1639 |
|
|
return doGet(key);
|
1640 |
|
|
}
|
1641 |
|
|
|
1642 |
|
|
/**
|
1643 |
|
|
* Associates the specified value with the specified key in this map.
|
1644 |
|
|
* If the map previously contained a mapping for the key, the old
|
1645 |
|
|
* value is replaced.
|
1646 |
|
|
*
|
1647 |
|
|
* @param key key with which the specified value is to be associated
|
1648 |
|
|
* @param value value to be associated with the specified key
|
1649 |
|
|
* @return the previous value associated with the specified key, or
|
1650 |
|
|
* <tt>null</tt> if there was no mapping for the key
|
1651 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1652 |
|
|
* with the keys currently in the map
|
1653 |
|
|
* @throws NullPointerException if the specified key or value is null
|
1654 |
|
|
*/
|
1655 |
|
|
public V put(K key, V value) {
|
1656 |
|
|
if (value == null)
|
1657 |
|
|
throw new NullPointerException();
|
1658 |
|
|
return doPut(key, value, false);
|
1659 |
|
|
}
|
1660 |
|
|
|
1661 |
|
|
/**
|
1662 |
|
|
* Removes the mapping for the specified key from this map if present.
|
1663 |
|
|
*
|
1664 |
|
|
* @param key key for which mapping should be removed
|
1665 |
|
|
* @return the previous value associated with the specified key, or
|
1666 |
|
|
* <tt>null</tt> if there was no mapping for the key
|
1667 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1668 |
|
|
* with the keys currently in the map
|
1669 |
|
|
* @throws NullPointerException if the specified key is null
|
1670 |
|
|
*/
|
1671 |
|
|
public V remove(Object key) {
|
1672 |
|
|
return doRemove(key, null);
|
1673 |
|
|
}
|
1674 |
|
|
|
1675 |
|
|
/**
|
1676 |
|
|
* Returns <tt>true</tt> if this map maps one or more keys to the
|
1677 |
|
|
* specified value. This operation requires time linear in the
|
1678 |
|
|
* map size.
|
1679 |
|
|
*
|
1680 |
|
|
* @param value value whose presence in this map is to be tested
|
1681 |
|
|
* @return <tt>true</tt> if a mapping to <tt>value</tt> exists;
|
1682 |
|
|
* <tt>false</tt> otherwise
|
1683 |
|
|
* @throws NullPointerException if the specified value is null
|
1684 |
|
|
*/
|
1685 |
|
|
public boolean containsValue(Object value) {
|
1686 |
|
|
if (value == null)
|
1687 |
|
|
throw new NullPointerException();
|
1688 |
|
|
for (Node<K,V> n = findFirst(); n != null; n = n.next) {
|
1689 |
|
|
V v = n.getValidValue();
|
1690 |
|
|
if (v != null && value.equals(v))
|
1691 |
|
|
return true;
|
1692 |
|
|
}
|
1693 |
|
|
return false;
|
1694 |
|
|
}
|
1695 |
|
|
|
1696 |
|
|
/**
|
1697 |
|
|
* Returns the number of key-value mappings in this map. If this map
|
1698 |
|
|
* contains more than <tt>Integer.MAX_VALUE</tt> elements, it
|
1699 |
|
|
* returns <tt>Integer.MAX_VALUE</tt>.
|
1700 |
|
|
*
|
1701 |
|
|
* <p>Beware that, unlike in most collections, this method is
|
1702 |
|
|
* <em>NOT</em> a constant-time operation. Because of the
|
1703 |
|
|
* asynchronous nature of these maps, determining the current
|
1704 |
|
|
* number of elements requires traversing them all to count them.
|
1705 |
|
|
* Additionally, it is possible for the size to change during
|
1706 |
|
|
* execution of this method, in which case the returned result
|
1707 |
|
|
* will be inaccurate. Thus, this method is typically not very
|
1708 |
|
|
* useful in concurrent applications.
|
1709 |
|
|
*
|
1710 |
|
|
* @return the number of elements in this map
|
1711 |
|
|
*/
|
1712 |
|
|
public int size() {
|
1713 |
|
|
long count = 0;
|
1714 |
|
|
for (Node<K,V> n = findFirst(); n != null; n = n.next) {
|
1715 |
|
|
if (n.getValidValue() != null)
|
1716 |
|
|
++count;
|
1717 |
|
|
}
|
1718 |
|
|
return (count >= Integer.MAX_VALUE)? Integer.MAX_VALUE : (int)count;
|
1719 |
|
|
}
|
1720 |
|
|
|
1721 |
|
|
/**
|
1722 |
|
|
* Returns <tt>true</tt> if this map contains no key-value mappings.
|
1723 |
|
|
* @return <tt>true</tt> if this map contains no key-value mappings
|
1724 |
|
|
*/
|
1725 |
|
|
public boolean isEmpty() {
|
1726 |
|
|
return findFirst() == null;
|
1727 |
|
|
}
|
1728 |
|
|
|
1729 |
|
|
/**
|
1730 |
|
|
* Removes all of the mappings from this map.
|
1731 |
|
|
*/
|
1732 |
|
|
public void clear() {
|
1733 |
|
|
initialize();
|
1734 |
|
|
}
|
1735 |
|
|
|
1736 |
|
|
/* ---------------- View methods -------------- */
|
1737 |
|
|
|
1738 |
|
|
/*
|
1739 |
|
|
* Note: Lazy initialization works for views because view classes
|
1740 |
|
|
* are stateless/immutable so it doesn't matter wrt correctness if
|
1741 |
|
|
* more than one is created (which will only rarely happen). Even
|
1742 |
|
|
* so, the following idiom conservatively ensures that the method
|
1743 |
|
|
* returns the one it created if it does so, not one created by
|
1744 |
|
|
* another racing thread.
|
1745 |
|
|
*/
|
1746 |
|
|
|
1747 |
|
|
/**
|
1748 |
|
|
* Returns a {@link NavigableSet} view of the keys contained in this map.
|
1749 |
|
|
* The set's iterator returns the keys in ascending order.
|
1750 |
|
|
* The set is backed by the map, so changes to the map are
|
1751 |
|
|
* reflected in the set, and vice-versa. The set supports element
|
1752 |
|
|
* removal, which removes the corresponding mapping from the map,
|
1753 |
|
|
* via the {@code Iterator.remove}, {@code Set.remove},
|
1754 |
|
|
* {@code removeAll}, {@code retainAll}, and {@code clear}
|
1755 |
|
|
* operations. It does not support the {@code add} or {@code addAll}
|
1756 |
|
|
* operations.
|
1757 |
|
|
*
|
1758 |
|
|
* <p>The view's {@code iterator} is a "weakly consistent" iterator
|
1759 |
|
|
* that will never throw {@link ConcurrentModificationException},
|
1760 |
|
|
* and guarantees to traverse elements as they existed upon
|
1761 |
|
|
* construction of the iterator, and may (but is not guaranteed to)
|
1762 |
|
|
* reflect any modifications subsequent to construction.
|
1763 |
|
|
*
|
1764 |
|
|
* <p>This method is equivalent to method {@code navigableKeySet}.
|
1765 |
|
|
*
|
1766 |
|
|
* @return a navigable set view of the keys in this map
|
1767 |
|
|
*/
|
1768 |
|
|
public NavigableSet<K> keySet() {
|
1769 |
|
|
KeySet ks = keySet;
|
1770 |
|
|
return (ks != null) ? ks : (keySet = new KeySet(this));
|
1771 |
|
|
}
|
1772 |
|
|
|
1773 |
|
|
public NavigableSet<K> navigableKeySet() {
|
1774 |
|
|
KeySet ks = keySet;
|
1775 |
|
|
return (ks != null) ? ks : (keySet = new KeySet(this));
|
1776 |
|
|
}
|
1777 |
|
|
|
1778 |
|
|
/**
|
1779 |
|
|
* Returns a {@link Collection} view of the values contained in this map.
|
1780 |
|
|
* The collection's iterator returns the values in ascending order
|
1781 |
|
|
* of the corresponding keys.
|
1782 |
|
|
* The collection is backed by the map, so changes to the map are
|
1783 |
|
|
* reflected in the collection, and vice-versa. The collection
|
1784 |
|
|
* supports element removal, which removes the corresponding
|
1785 |
|
|
* mapping from the map, via the <tt>Iterator.remove</tt>,
|
1786 |
|
|
* <tt>Collection.remove</tt>, <tt>removeAll</tt>,
|
1787 |
|
|
* <tt>retainAll</tt> and <tt>clear</tt> operations. It does not
|
1788 |
|
|
* support the <tt>add</tt> or <tt>addAll</tt> operations.
|
1789 |
|
|
*
|
1790 |
|
|
* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
|
1791 |
|
|
* that will never throw {@link ConcurrentModificationException},
|
1792 |
|
|
* and guarantees to traverse elements as they existed upon
|
1793 |
|
|
* construction of the iterator, and may (but is not guaranteed to)
|
1794 |
|
|
* reflect any modifications subsequent to construction.
|
1795 |
|
|
*/
|
1796 |
|
|
public Collection<V> values() {
|
1797 |
|
|
Values vs = values;
|
1798 |
|
|
return (vs != null) ? vs : (values = new Values(this));
|
1799 |
|
|
}
|
1800 |
|
|
|
1801 |
|
|
/**
|
1802 |
|
|
* Returns a {@link Set} view of the mappings contained in this map.
|
1803 |
|
|
* The set's iterator returns the entries in ascending key order.
|
1804 |
|
|
* The set is backed by the map, so changes to the map are
|
1805 |
|
|
* reflected in the set, and vice-versa. The set supports element
|
1806 |
|
|
* removal, which removes the corresponding mapping from the map,
|
1807 |
|
|
* via the <tt>Iterator.remove</tt>, <tt>Set.remove</tt>,
|
1808 |
|
|
* <tt>removeAll</tt>, <tt>retainAll</tt> and <tt>clear</tt>
|
1809 |
|
|
* operations. It does not support the <tt>add</tt> or
|
1810 |
|
|
* <tt>addAll</tt> operations.
|
1811 |
|
|
*
|
1812 |
|
|
* <p>The view's <tt>iterator</tt> is a "weakly consistent" iterator
|
1813 |
|
|
* that will never throw {@link ConcurrentModificationException},
|
1814 |
|
|
* and guarantees to traverse elements as they existed upon
|
1815 |
|
|
* construction of the iterator, and may (but is not guaranteed to)
|
1816 |
|
|
* reflect any modifications subsequent to construction.
|
1817 |
|
|
*
|
1818 |
|
|
* <p>The <tt>Map.Entry</tt> elements returned by
|
1819 |
|
|
* <tt>iterator.next()</tt> do <em>not</em> support the
|
1820 |
|
|
* <tt>setValue</tt> operation.
|
1821 |
|
|
*
|
1822 |
|
|
* @return a set view of the mappings contained in this map,
|
1823 |
|
|
* sorted in ascending key order
|
1824 |
|
|
*/
|
1825 |
|
|
public Set<Map.Entry<K,V>> entrySet() {
|
1826 |
|
|
EntrySet es = entrySet;
|
1827 |
|
|
return (es != null) ? es : (entrySet = new EntrySet(this));
|
1828 |
|
|
}
|
1829 |
|
|
|
1830 |
|
|
public ConcurrentNavigableMap<K,V> descendingMap() {
|
1831 |
|
|
ConcurrentNavigableMap<K,V> dm = descendingMap;
|
1832 |
|
|
return (dm != null) ? dm : (descendingMap = new SubMap<K,V>
|
1833 |
|
|
(this, null, false, null, false, true));
|
1834 |
|
|
}
|
1835 |
|
|
|
1836 |
|
|
public NavigableSet<K> descendingKeySet() {
|
1837 |
|
|
return descendingMap().navigableKeySet();
|
1838 |
|
|
}
|
1839 |
|
|
|
1840 |
|
|
/* ---------------- AbstractMap Overrides -------------- */
|
1841 |
|
|
|
1842 |
|
|
/**
|
1843 |
|
|
* Compares the specified object with this map for equality.
|
1844 |
|
|
* Returns <tt>true</tt> if the given object is also a map and the
|
1845 |
|
|
* two maps represent the same mappings. More formally, two maps
|
1846 |
|
|
* <tt>m1</tt> and <tt>m2</tt> represent the same mappings if
|
1847 |
|
|
* <tt>m1.entrySet().equals(m2.entrySet())</tt>. This
|
1848 |
|
|
* operation may return misleading results if either map is
|
1849 |
|
|
* concurrently modified during execution of this method.
|
1850 |
|
|
*
|
1851 |
|
|
* @param o object to be compared for equality with this map
|
1852 |
|
|
* @return <tt>true</tt> if the specified object is equal to this map
|
1853 |
|
|
*/
|
1854 |
|
|
public boolean equals(Object o) {
|
1855 |
|
|
if (o == this)
|
1856 |
|
|
return true;
|
1857 |
|
|
if (!(o instanceof Map))
|
1858 |
|
|
return false;
|
1859 |
|
|
Map<?,?> m = (Map<?,?>) o;
|
1860 |
|
|
try {
|
1861 |
|
|
for (Map.Entry<K,V> e : this.entrySet())
|
1862 |
|
|
if (! e.getValue().equals(m.get(e.getKey())))
|
1863 |
|
|
return false;
|
1864 |
|
|
for (Map.Entry<?,?> e : m.entrySet()) {
|
1865 |
|
|
Object k = e.getKey();
|
1866 |
|
|
Object v = e.getValue();
|
1867 |
|
|
if (k == null || v == null || !v.equals(get(k)))
|
1868 |
|
|
return false;
|
1869 |
|
|
}
|
1870 |
|
|
return true;
|
1871 |
|
|
} catch (ClassCastException unused) {
|
1872 |
|
|
return false;
|
1873 |
|
|
} catch (NullPointerException unused) {
|
1874 |
|
|
return false;
|
1875 |
|
|
}
|
1876 |
|
|
}
|
1877 |
|
|
|
1878 |
|
|
/* ------ ConcurrentMap API methods ------ */
|
1879 |
|
|
|
1880 |
|
|
/**
|
1881 |
|
|
* {@inheritDoc}
|
1882 |
|
|
*
|
1883 |
|
|
* @return the previous value associated with the specified key,
|
1884 |
|
|
* or <tt>null</tt> if there was no mapping for the key
|
1885 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1886 |
|
|
* with the keys currently in the map
|
1887 |
|
|
* @throws NullPointerException if the specified key or value is null
|
1888 |
|
|
*/
|
1889 |
|
|
public V putIfAbsent(K key, V value) {
|
1890 |
|
|
if (value == null)
|
1891 |
|
|
throw new NullPointerException();
|
1892 |
|
|
return doPut(key, value, true);
|
1893 |
|
|
}
|
1894 |
|
|
|
1895 |
|
|
/**
|
1896 |
|
|
* {@inheritDoc}
|
1897 |
|
|
*
|
1898 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1899 |
|
|
* with the keys currently in the map
|
1900 |
|
|
* @throws NullPointerException if the specified key is null
|
1901 |
|
|
*/
|
1902 |
|
|
public boolean remove(Object key, Object value) {
|
1903 |
|
|
if (key == null)
|
1904 |
|
|
throw new NullPointerException();
|
1905 |
|
|
if (value == null)
|
1906 |
|
|
return false;
|
1907 |
|
|
return doRemove(key, value) != null;
|
1908 |
|
|
}
|
1909 |
|
|
|
1910 |
|
|
/**
|
1911 |
|
|
* {@inheritDoc}
|
1912 |
|
|
*
|
1913 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1914 |
|
|
* with the keys currently in the map
|
1915 |
|
|
* @throws NullPointerException if any of the arguments are null
|
1916 |
|
|
*/
|
1917 |
|
|
public boolean replace(K key, V oldValue, V newValue) {
|
1918 |
|
|
if (oldValue == null || newValue == null)
|
1919 |
|
|
throw new NullPointerException();
|
1920 |
|
|
Comparable<? super K> k = comparable(key);
|
1921 |
|
|
for (;;) {
|
1922 |
|
|
Node<K,V> n = findNode(k);
|
1923 |
|
|
if (n == null)
|
1924 |
|
|
return false;
|
1925 |
|
|
Object v = n.value;
|
1926 |
|
|
if (v != null) {
|
1927 |
|
|
if (!oldValue.equals(v))
|
1928 |
|
|
return false;
|
1929 |
|
|
if (n.casValue(v, newValue))
|
1930 |
|
|
return true;
|
1931 |
|
|
}
|
1932 |
|
|
}
|
1933 |
|
|
}
|
1934 |
|
|
|
1935 |
|
|
/**
|
1936 |
|
|
* {@inheritDoc}
|
1937 |
|
|
*
|
1938 |
|
|
* @return the previous value associated with the specified key,
|
1939 |
|
|
* or <tt>null</tt> if there was no mapping for the key
|
1940 |
|
|
* @throws ClassCastException if the specified key cannot be compared
|
1941 |
|
|
* with the keys currently in the map
|
1942 |
|
|
* @throws NullPointerException if the specified key or value is null
|
1943 |
|
|
*/
|
1944 |
|
|
public V replace(K key, V value) {
|
1945 |
|
|
if (value == null)
|
1946 |
|
|
throw new NullPointerException();
|
1947 |
|
|
Comparable<? super K> k = comparable(key);
|
1948 |
|
|
for (;;) {
|
1949 |
|
|
Node<K,V> n = findNode(k);
|
1950 |
|
|
if (n == null)
|
1951 |
|
|
return null;
|
1952 |
|
|
Object v = n.value;
|
1953 |
|
|
if (v != null && n.casValue(v, value))
|
1954 |
|
|
return (V)v;
|
1955 |
|
|
}
|
1956 |
|
|
}
|
1957 |
|
|
|
1958 |
|
|
/* ------ SortedMap API methods ------ */
|
1959 |
|
|
|
1960 |
|
|
public Comparator<? super K> comparator() {
|
1961 |
|
|
return comparator;
|
1962 |
|
|
}
|
1963 |
|
|
|
1964 |
|
|
/**
|
1965 |
|
|
* @throws NoSuchElementException {@inheritDoc}
|
1966 |
|
|
*/
|
1967 |
|
|
public K firstKey() {
|
1968 |
|
|
Node<K,V> n = findFirst();
|
1969 |
|
|
if (n == null)
|
1970 |
|
|
throw new NoSuchElementException();
|
1971 |
|
|
return n.key;
|
1972 |
|
|
}
|
1973 |
|
|
|
1974 |
|
|
/**
|
1975 |
|
|
* @throws NoSuchElementException {@inheritDoc}
|
1976 |
|
|
*/
|
1977 |
|
|
public K lastKey() {
|
1978 |
|
|
Node<K,V> n = findLast();
|
1979 |
|
|
if (n == null)
|
1980 |
|
|
throw new NoSuchElementException();
|
1981 |
|
|
return n.key;
|
1982 |
|
|
}
|
1983 |
|
|
|
1984 |
|
|
/**
|
1985 |
|
|
* @throws ClassCastException {@inheritDoc}
|
1986 |
|
|
* @throws NullPointerException if {@code fromKey} or {@code toKey} is null
|
1987 |
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
1988 |
|
|
*/
|
1989 |
|
|
public ConcurrentNavigableMap<K,V> subMap(K fromKey,
|
1990 |
|
|
boolean fromInclusive,
|
1991 |
|
|
K toKey,
|
1992 |
|
|
boolean toInclusive) {
|
1993 |
|
|
if (fromKey == null || toKey == null)
|
1994 |
|
|
throw new NullPointerException();
|
1995 |
|
|
return new SubMap<K,V>
|
1996 |
|
|
(this, fromKey, fromInclusive, toKey, toInclusive, false);
|
1997 |
|
|
}
|
1998 |
|
|
|
1999 |
|
|
/**
|
2000 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2001 |
|
|
* @throws NullPointerException if {@code toKey} is null
|
2002 |
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
2003 |
|
|
*/
|
2004 |
|
|
public ConcurrentNavigableMap<K,V> headMap(K toKey,
|
2005 |
|
|
boolean inclusive) {
|
2006 |
|
|
if (toKey == null)
|
2007 |
|
|
throw new NullPointerException();
|
2008 |
|
|
return new SubMap<K,V>
|
2009 |
|
|
(this, null, false, toKey, inclusive, false);
|
2010 |
|
|
}
|
2011 |
|
|
|
2012 |
|
|
/**
|
2013 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2014 |
|
|
* @throws NullPointerException if {@code fromKey} is null
|
2015 |
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
2016 |
|
|
*/
|
2017 |
|
|
public ConcurrentNavigableMap<K,V> tailMap(K fromKey,
|
2018 |
|
|
boolean inclusive) {
|
2019 |
|
|
if (fromKey == null)
|
2020 |
|
|
throw new NullPointerException();
|
2021 |
|
|
return new SubMap<K,V>
|
2022 |
|
|
(this, fromKey, inclusive, null, false, false);
|
2023 |
|
|
}
|
2024 |
|
|
|
2025 |
|
|
/**
|
2026 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2027 |
|
|
* @throws NullPointerException if {@code fromKey} or {@code toKey} is null
|
2028 |
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
2029 |
|
|
*/
|
2030 |
|
|
public ConcurrentNavigableMap<K,V> subMap(K fromKey, K toKey) {
|
2031 |
|
|
return subMap(fromKey, true, toKey, false);
|
2032 |
|
|
}
|
2033 |
|
|
|
2034 |
|
|
/**
|
2035 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2036 |
|
|
* @throws NullPointerException if {@code toKey} is null
|
2037 |
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
2038 |
|
|
*/
|
2039 |
|
|
public ConcurrentNavigableMap<K,V> headMap(K toKey) {
|
2040 |
|
|
return headMap(toKey, false);
|
2041 |
|
|
}
|
2042 |
|
|
|
2043 |
|
|
/**
|
2044 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2045 |
|
|
* @throws NullPointerException if {@code fromKey} is null
|
2046 |
|
|
* @throws IllegalArgumentException {@inheritDoc}
|
2047 |
|
|
*/
|
2048 |
|
|
public ConcurrentNavigableMap<K,V> tailMap(K fromKey) {
|
2049 |
|
|
return tailMap(fromKey, true);
|
2050 |
|
|
}
|
2051 |
|
|
|
2052 |
|
|
/* ---------------- Relational operations -------------- */
|
2053 |
|
|
|
2054 |
|
|
/**
|
2055 |
|
|
* Returns a key-value mapping associated with the greatest key
|
2056 |
|
|
* strictly less than the given key, or <tt>null</tt> if there is
|
2057 |
|
|
* no such key. The returned entry does <em>not</em> support the
|
2058 |
|
|
* <tt>Entry.setValue</tt> method.
|
2059 |
|
|
*
|
2060 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2061 |
|
|
* @throws NullPointerException if the specified key is null
|
2062 |
|
|
*/
|
2063 |
|
|
public Map.Entry<K,V> lowerEntry(K key) {
|
2064 |
|
|
return getNear(key, LT);
|
2065 |
|
|
}
|
2066 |
|
|
|
2067 |
|
|
/**
|
2068 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2069 |
|
|
* @throws NullPointerException if the specified key is null
|
2070 |
|
|
*/
|
2071 |
|
|
public K lowerKey(K key) {
|
2072 |
|
|
Node<K,V> n = findNear(key, LT);
|
2073 |
|
|
return (n == null)? null : n.key;
|
2074 |
|
|
}
|
2075 |
|
|
|
2076 |
|
|
/**
|
2077 |
|
|
* Returns a key-value mapping associated with the greatest key
|
2078 |
|
|
* less than or equal to the given key, or <tt>null</tt> if there
|
2079 |
|
|
* is no such key. The returned entry does <em>not</em> support
|
2080 |
|
|
* the <tt>Entry.setValue</tt> method.
|
2081 |
|
|
*
|
2082 |
|
|
* @param key the key
|
2083 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2084 |
|
|
* @throws NullPointerException if the specified key is null
|
2085 |
|
|
*/
|
2086 |
|
|
public Map.Entry<K,V> floorEntry(K key) {
|
2087 |
|
|
return getNear(key, LT|EQ);
|
2088 |
|
|
}
|
2089 |
|
|
|
2090 |
|
|
/**
|
2091 |
|
|
* @param key the key
|
2092 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2093 |
|
|
* @throws NullPointerException if the specified key is null
|
2094 |
|
|
*/
|
2095 |
|
|
public K floorKey(K key) {
|
2096 |
|
|
Node<K,V> n = findNear(key, LT|EQ);
|
2097 |
|
|
return (n == null)? null : n.key;
|
2098 |
|
|
}
|
2099 |
|
|
|
2100 |
|
|
/**
|
2101 |
|
|
* Returns a key-value mapping associated with the least key
|
2102 |
|
|
* greater than or equal to the given key, or <tt>null</tt> if
|
2103 |
|
|
* there is no such entry. The returned entry does <em>not</em>
|
2104 |
|
|
* support the <tt>Entry.setValue</tt> method.
|
2105 |
|
|
*
|
2106 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2107 |
|
|
* @throws NullPointerException if the specified key is null
|
2108 |
|
|
*/
|
2109 |
|
|
public Map.Entry<K,V> ceilingEntry(K key) {
|
2110 |
|
|
return getNear(key, GT|EQ);
|
2111 |
|
|
}
|
2112 |
|
|
|
2113 |
|
|
/**
|
2114 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2115 |
|
|
* @throws NullPointerException if the specified key is null
|
2116 |
|
|
*/
|
2117 |
|
|
public K ceilingKey(K key) {
|
2118 |
|
|
Node<K,V> n = findNear(key, GT|EQ);
|
2119 |
|
|
return (n == null)? null : n.key;
|
2120 |
|
|
}
|
2121 |
|
|
|
2122 |
|
|
/**
|
2123 |
|
|
* Returns a key-value mapping associated with the least key
|
2124 |
|
|
* strictly greater than the given key, or <tt>null</tt> if there
|
2125 |
|
|
* is no such key. The returned entry does <em>not</em> support
|
2126 |
|
|
* the <tt>Entry.setValue</tt> method.
|
2127 |
|
|
*
|
2128 |
|
|
* @param key the key
|
2129 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2130 |
|
|
* @throws NullPointerException if the specified key is null
|
2131 |
|
|
*/
|
2132 |
|
|
public Map.Entry<K,V> higherEntry(K key) {
|
2133 |
|
|
return getNear(key, GT);
|
2134 |
|
|
}
|
2135 |
|
|
|
2136 |
|
|
/**
|
2137 |
|
|
* @param key the key
|
2138 |
|
|
* @throws ClassCastException {@inheritDoc}
|
2139 |
|
|
* @throws NullPointerException if the specified key is null
|
2140 |
|
|
*/
|
2141 |
|
|
public K higherKey(K key) {
|
2142 |
|
|
Node<K,V> n = findNear(key, GT);
|
2143 |
|
|
return (n == null)? null : n.key;
|
2144 |
|
|
}
|
2145 |
|
|
|
2146 |
|
|
/**
|
2147 |
|
|
* Returns a key-value mapping associated with the least
|
2148 |
|
|
* key in this map, or <tt>null</tt> if the map is empty.
|
2149 |
|
|
* The returned entry does <em>not</em> support
|
2150 |
|
|
* the <tt>Entry.setValue</tt> method.
|
2151 |
|
|
*/
|
2152 |
|
|
public Map.Entry<K,V> firstEntry() {
|
2153 |
|
|
for (;;) {
|
2154 |
|
|
Node<K,V> n = findFirst();
|
2155 |
|
|
if (n == null)
|
2156 |
|
|
return null;
|
2157 |
|
|
AbstractMap.SimpleImmutableEntry<K,V> e = n.createSnapshot();
|
2158 |
|
|
if (e != null)
|
2159 |
|
|
return e;
|
2160 |
|
|
}
|
2161 |
|
|
}
|
2162 |
|
|
|
2163 |
|
|
/**
|
2164 |
|
|
* Returns a key-value mapping associated with the greatest
|
2165 |
|
|
* key in this map, or <tt>null</tt> if the map is empty.
|
2166 |
|
|
* The returned entry does <em>not</em> support
|
2167 |
|
|
* the <tt>Entry.setValue</tt> method.
|
2168 |
|
|
*/
|
2169 |
|
|
public Map.Entry<K,V> lastEntry() {
|
2170 |
|
|
for (;;) {
|
2171 |
|
|
Node<K,V> n = findLast();
|
2172 |
|
|
if (n == null)
|
2173 |
|
|
return null;
|
2174 |
|
|
AbstractMap.SimpleImmutableEntry<K,V> e = n.createSnapshot();
|
2175 |
|
|
if (e != null)
|
2176 |
|
|
return e;
|
2177 |
|
|
}
|
2178 |
|
|
}
|
2179 |
|
|
|
2180 |
|
|
/**
|
2181 |
|
|
* Removes and returns a key-value mapping associated with
|
2182 |
|
|
* the least key in this map, or <tt>null</tt> if the map is empty.
|
2183 |
|
|
* The returned entry does <em>not</em> support
|
2184 |
|
|
* the <tt>Entry.setValue</tt> method.
|
2185 |
|
|
*/
|
2186 |
|
|
public Map.Entry<K,V> pollFirstEntry() {
|
2187 |
|
|
return doRemoveFirstEntry();
|
2188 |
|
|
}
|
2189 |
|
|
|
2190 |
|
|
/**
|
2191 |
|
|
* Removes and returns a key-value mapping associated with
|
2192 |
|
|
* the greatest key in this map, or <tt>null</tt> if the map is empty.
|
2193 |
|
|
* The returned entry does <em>not</em> support
|
2194 |
|
|
* the <tt>Entry.setValue</tt> method.
|
2195 |
|
|
*/
|
2196 |
|
|
public Map.Entry<K,V> pollLastEntry() {
|
2197 |
|
|
return doRemoveLastEntry();
|
2198 |
|
|
}
|
2199 |
|
|
|
2200 |
|
|
|
2201 |
|
|
/* ---------------- Iterators -------------- */
|
2202 |
|
|
|
2203 |
|
|
/**
|
2204 |
|
|
* Base of iterator classes:
|
2205 |
|
|
*/
|
2206 |
|
|
abstract class Iter<T> implements Iterator<T> {
|
2207 |
|
|
/** the last node returned by next() */
|
2208 |
|
|
Node<K,V> lastReturned;
|
2209 |
|
|
/** the next node to return from next(); */
|
2210 |
|
|
Node<K,V> next;
|
2211 |
|
|
/** Cache of next value field to maintain weak consistency */
|
2212 |
|
|
V nextValue;
|
2213 |
|
|
|
2214 |
|
|
/** Initializes ascending iterator for entire range. */
|
2215 |
|
|
Iter() {
|
2216 |
|
|
for (;;) {
|
2217 |
|
|
next = findFirst();
|
2218 |
|
|
if (next == null)
|
2219 |
|
|
break;
|
2220 |
|
|
Object x = next.value;
|
2221 |
|
|
if (x != null && x != next) {
|
2222 |
|
|
nextValue = (V) x;
|
2223 |
|
|
break;
|
2224 |
|
|
}
|
2225 |
|
|
}
|
2226 |
|
|
}
|
2227 |
|
|
|
2228 |
|
|
public final boolean hasNext() {
|
2229 |
|
|
return next != null;
|
2230 |
|
|
}
|
2231 |
|
|
|
2232 |
|
|
/** Advances next to higher entry. */
|
2233 |
|
|
final void advance() {
|
2234 |
|
|
if ((lastReturned = next) == null)
|
2235 |
|
|
throw new NoSuchElementException();
|
2236 |
|
|
for (;;) {
|
2237 |
|
|
next = next.next;
|
2238 |
|
|
if (next == null)
|
2239 |
|
|
break;
|
2240 |
|
|
Object x = next.value;
|
2241 |
|
|
if (x != null && x != next) {
|
2242 |
|
|
nextValue = (V) x;
|
2243 |
|
|
break;
|
2244 |
|
|
}
|
2245 |
|
|
}
|
2246 |
|
|
}
|
2247 |
|
|
|
2248 |
|
|
public void remove() {
|
2249 |
|
|
Node<K,V> l = lastReturned;
|
2250 |
|
|
if (l == null)
|
2251 |
|
|
throw new IllegalStateException();
|
2252 |
|
|
// It would not be worth all of the overhead to directly
|
2253 |
|
|
// unlink from here. Using remove is fast enough.
|
2254 |
|
|
ConcurrentSkipListMap.this.remove(l.key);
|
2255 |
|
|
lastReturned = null;
|
2256 |
|
|
}
|
2257 |
|
|
|
2258 |
|
|
}
|
2259 |
|
|
|
2260 |
|
|
final class ValueIterator extends Iter<V> {
|
2261 |
|
|
public V next() {
|
2262 |
|
|
V v = nextValue;
|
2263 |
|
|
advance();
|
2264 |
|
|
return v;
|
2265 |
|
|
}
|
2266 |
|
|
}
|
2267 |
|
|
|
2268 |
|
|
final class KeyIterator extends Iter<K> {
|
2269 |
|
|
public K next() {
|
2270 |
|
|
Node<K,V> n = next;
|
2271 |
|
|
advance();
|
2272 |
|
|
return n.key;
|
2273 |
|
|
}
|
2274 |
|
|
}
|
2275 |
|
|
|
2276 |
|
|
final class EntryIterator extends Iter<Map.Entry<K,V>> {
|
2277 |
|
|
public Map.Entry<K,V> next() {
|
2278 |
|
|
Node<K,V> n = next;
|
2279 |
|
|
V v = nextValue;
|
2280 |
|
|
advance();
|
2281 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(n.key, v);
|
2282 |
|
|
}
|
2283 |
|
|
}
|
2284 |
|
|
|
2285 |
|
|
// Factory methods for iterators needed by ConcurrentSkipListSet etc
|
2286 |
|
|
|
2287 |
|
|
Iterator<K> keyIterator() {
|
2288 |
|
|
return new KeyIterator();
|
2289 |
|
|
}
|
2290 |
|
|
|
2291 |
|
|
Iterator<V> valueIterator() {
|
2292 |
|
|
return new ValueIterator();
|
2293 |
|
|
}
|
2294 |
|
|
|
2295 |
|
|
Iterator<Map.Entry<K,V>> entryIterator() {
|
2296 |
|
|
return new EntryIterator();
|
2297 |
|
|
}
|
2298 |
|
|
|
2299 |
|
|
/* ---------------- View Classes -------------- */
|
2300 |
|
|
|
2301 |
|
|
/*
|
2302 |
|
|
* View classes are static, delegating to a ConcurrentNavigableMap
|
2303 |
|
|
* to allow use by SubMaps, which outweighs the ugliness of
|
2304 |
|
|
* needing type-tests for Iterator methods.
|
2305 |
|
|
*/
|
2306 |
|
|
|
2307 |
|
|
static final <E> List<E> toList(Collection<E> c) {
|
2308 |
|
|
// Using size() here would be a pessimization.
|
2309 |
|
|
List<E> list = new ArrayList<E>();
|
2310 |
|
|
for (E e : c)
|
2311 |
|
|
list.add(e);
|
2312 |
|
|
return list;
|
2313 |
|
|
}
|
2314 |
|
|
|
2315 |
|
|
static final class KeySet<E> extends AbstractSet<E> implements NavigableSet<E> {
|
2316 |
|
|
private final ConcurrentNavigableMap<E,Object> m;
|
2317 |
|
|
KeySet(ConcurrentNavigableMap<E,Object> map) { m = map; }
|
2318 |
|
|
public int size() { return m.size(); }
|
2319 |
|
|
public boolean isEmpty() { return m.isEmpty(); }
|
2320 |
|
|
public boolean contains(Object o) { return m.containsKey(o); }
|
2321 |
|
|
public boolean remove(Object o) { return m.remove(o) != null; }
|
2322 |
|
|
public void clear() { m.clear(); }
|
2323 |
|
|
public E lower(E e) { return m.lowerKey(e); }
|
2324 |
|
|
public E floor(E e) { return m.floorKey(e); }
|
2325 |
|
|
public E ceiling(E e) { return m.ceilingKey(e); }
|
2326 |
|
|
public E higher(E e) { return m.higherKey(e); }
|
2327 |
|
|
public Comparator<? super E> comparator() { return m.comparator(); }
|
2328 |
|
|
public E first() { return m.firstKey(); }
|
2329 |
|
|
public E last() { return m.lastKey(); }
|
2330 |
|
|
public E pollFirst() {
|
2331 |
|
|
Map.Entry<E,Object> e = m.pollFirstEntry();
|
2332 |
|
|
return e == null? null : e.getKey();
|
2333 |
|
|
}
|
2334 |
|
|
public E pollLast() {
|
2335 |
|
|
Map.Entry<E,Object> e = m.pollLastEntry();
|
2336 |
|
|
return e == null? null : e.getKey();
|
2337 |
|
|
}
|
2338 |
|
|
public Iterator<E> iterator() {
|
2339 |
|
|
if (m instanceof ConcurrentSkipListMap)
|
2340 |
|
|
return ((ConcurrentSkipListMap<E,Object>)m).keyIterator();
|
2341 |
|
|
else
|
2342 |
|
|
return ((ConcurrentSkipListMap.SubMap<E,Object>)m).keyIterator();
|
2343 |
|
|
}
|
2344 |
|
|
public boolean equals(Object o) {
|
2345 |
|
|
if (o == this)
|
2346 |
|
|
return true;
|
2347 |
|
|
if (!(o instanceof Set))
|
2348 |
|
|
return false;
|
2349 |
|
|
Collection<?> c = (Collection<?>) o;
|
2350 |
|
|
try {
|
2351 |
|
|
return containsAll(c) && c.containsAll(this);
|
2352 |
|
|
} catch (ClassCastException unused) {
|
2353 |
|
|
return false;
|
2354 |
|
|
} catch (NullPointerException unused) {
|
2355 |
|
|
return false;
|
2356 |
|
|
}
|
2357 |
|
|
}
|
2358 |
|
|
public Object[] toArray() { return toList(this).toArray(); }
|
2359 |
|
|
public <T> T[] toArray(T[] a) { return toList(this).toArray(a); }
|
2360 |
|
|
public Iterator<E> descendingIterator() {
|
2361 |
|
|
return descendingSet().iterator();
|
2362 |
|
|
}
|
2363 |
|
|
public NavigableSet<E> subSet(E fromElement,
|
2364 |
|
|
boolean fromInclusive,
|
2365 |
|
|
E toElement,
|
2366 |
|
|
boolean toInclusive) {
|
2367 |
|
|
return new ConcurrentSkipListSet<E>
|
2368 |
|
|
(m.subMap(fromElement, fromInclusive,
|
2369 |
|
|
toElement, toInclusive));
|
2370 |
|
|
}
|
2371 |
|
|
public NavigableSet<E> headSet(E toElement, boolean inclusive) {
|
2372 |
|
|
return new ConcurrentSkipListSet<E>(m.headMap(toElement, inclusive));
|
2373 |
|
|
}
|
2374 |
|
|
public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
|
2375 |
|
|
return new ConcurrentSkipListSet<E>(m.tailMap(fromElement, inclusive));
|
2376 |
|
|
}
|
2377 |
|
|
public NavigableSet<E> subSet(E fromElement, E toElement) {
|
2378 |
|
|
return subSet(fromElement, true, toElement, false);
|
2379 |
|
|
}
|
2380 |
|
|
public NavigableSet<E> headSet(E toElement) {
|
2381 |
|
|
return headSet(toElement, false);
|
2382 |
|
|
}
|
2383 |
|
|
public NavigableSet<E> tailSet(E fromElement) {
|
2384 |
|
|
return tailSet(fromElement, true);
|
2385 |
|
|
}
|
2386 |
|
|
public NavigableSet<E> descendingSet() {
|
2387 |
|
|
return new ConcurrentSkipListSet(m.descendingMap());
|
2388 |
|
|
}
|
2389 |
|
|
}
|
2390 |
|
|
|
2391 |
|
|
static final class Values<E> extends AbstractCollection<E> {
|
2392 |
|
|
private final ConcurrentNavigableMap<Object, E> m;
|
2393 |
|
|
Values(ConcurrentNavigableMap<Object, E> map) {
|
2394 |
|
|
m = map;
|
2395 |
|
|
}
|
2396 |
|
|
public Iterator<E> iterator() {
|
2397 |
|
|
if (m instanceof ConcurrentSkipListMap)
|
2398 |
|
|
return ((ConcurrentSkipListMap<Object,E>)m).valueIterator();
|
2399 |
|
|
else
|
2400 |
|
|
return ((SubMap<Object,E>)m).valueIterator();
|
2401 |
|
|
}
|
2402 |
|
|
public boolean isEmpty() {
|
2403 |
|
|
return m.isEmpty();
|
2404 |
|
|
}
|
2405 |
|
|
public int size() {
|
2406 |
|
|
return m.size();
|
2407 |
|
|
}
|
2408 |
|
|
public boolean contains(Object o) {
|
2409 |
|
|
return m.containsValue(o);
|
2410 |
|
|
}
|
2411 |
|
|
public void clear() {
|
2412 |
|
|
m.clear();
|
2413 |
|
|
}
|
2414 |
|
|
public Object[] toArray() { return toList(this).toArray(); }
|
2415 |
|
|
public <T> T[] toArray(T[] a) { return toList(this).toArray(a); }
|
2416 |
|
|
}
|
2417 |
|
|
|
2418 |
|
|
static final class EntrySet<K1,V1> extends AbstractSet<Map.Entry<K1,V1>> {
|
2419 |
|
|
private final ConcurrentNavigableMap<K1, V1> m;
|
2420 |
|
|
EntrySet(ConcurrentNavigableMap<K1, V1> map) {
|
2421 |
|
|
m = map;
|
2422 |
|
|
}
|
2423 |
|
|
|
2424 |
|
|
public Iterator<Map.Entry<K1,V1>> iterator() {
|
2425 |
|
|
if (m instanceof ConcurrentSkipListMap)
|
2426 |
|
|
return ((ConcurrentSkipListMap<K1,V1>)m).entryIterator();
|
2427 |
|
|
else
|
2428 |
|
|
return ((SubMap<K1,V1>)m).entryIterator();
|
2429 |
|
|
}
|
2430 |
|
|
|
2431 |
|
|
public boolean contains(Object o) {
|
2432 |
|
|
if (!(o instanceof Map.Entry))
|
2433 |
|
|
return false;
|
2434 |
|
|
Map.Entry<K1,V1> e = (Map.Entry<K1,V1>)o;
|
2435 |
|
|
V1 v = m.get(e.getKey());
|
2436 |
|
|
return v != null && v.equals(e.getValue());
|
2437 |
|
|
}
|
2438 |
|
|
public boolean remove(Object o) {
|
2439 |
|
|
if (!(o instanceof Map.Entry))
|
2440 |
|
|
return false;
|
2441 |
|
|
Map.Entry<K1,V1> e = (Map.Entry<K1,V1>)o;
|
2442 |
|
|
return m.remove(e.getKey(),
|
2443 |
|
|
e.getValue());
|
2444 |
|
|
}
|
2445 |
|
|
public boolean isEmpty() {
|
2446 |
|
|
return m.isEmpty();
|
2447 |
|
|
}
|
2448 |
|
|
public int size() {
|
2449 |
|
|
return m.size();
|
2450 |
|
|
}
|
2451 |
|
|
public void clear() {
|
2452 |
|
|
m.clear();
|
2453 |
|
|
}
|
2454 |
|
|
public boolean equals(Object o) {
|
2455 |
|
|
if (o == this)
|
2456 |
|
|
return true;
|
2457 |
|
|
if (!(o instanceof Set))
|
2458 |
|
|
return false;
|
2459 |
|
|
Collection<?> c = (Collection<?>) o;
|
2460 |
|
|
try {
|
2461 |
|
|
return containsAll(c) && c.containsAll(this);
|
2462 |
|
|
} catch (ClassCastException unused) {
|
2463 |
|
|
return false;
|
2464 |
|
|
} catch (NullPointerException unused) {
|
2465 |
|
|
return false;
|
2466 |
|
|
}
|
2467 |
|
|
}
|
2468 |
|
|
public Object[] toArray() { return toList(this).toArray(); }
|
2469 |
|
|
public <T> T[] toArray(T[] a) { return toList(this).toArray(a); }
|
2470 |
|
|
}
|
2471 |
|
|
|
2472 |
|
|
/**
|
2473 |
|
|
* Submaps returned by {@link ConcurrentSkipListMap} submap operations
|
2474 |
|
|
* represent a subrange of mappings of their underlying
|
2475 |
|
|
* maps. Instances of this class support all methods of their
|
2476 |
|
|
* underlying maps, differing in that mappings outside their range are
|
2477 |
|
|
* ignored, and attempts to add mappings outside their ranges result
|
2478 |
|
|
* in {@link IllegalArgumentException}. Instances of this class are
|
2479 |
|
|
* constructed only using the <tt>subMap</tt>, <tt>headMap</tt>, and
|
2480 |
|
|
* <tt>tailMap</tt> methods of their underlying maps.
|
2481 |
|
|
*
|
2482 |
|
|
* @serial include
|
2483 |
|
|
*/
|
2484 |
|
|
static final class SubMap<K,V> extends AbstractMap<K,V>
|
2485 |
|
|
implements ConcurrentNavigableMap<K,V>, Cloneable,
|
2486 |
|
|
java.io.Serializable {
|
2487 |
|
|
private static final long serialVersionUID = -7647078645895051609L;
|
2488 |
|
|
|
2489 |
|
|
/** Underlying map */
|
2490 |
|
|
private final ConcurrentSkipListMap<K,V> m;
|
2491 |
|
|
/** lower bound key, or null if from start */
|
2492 |
|
|
private final K lo;
|
2493 |
|
|
/** upper bound key, or null if to end */
|
2494 |
|
|
private final K hi;
|
2495 |
|
|
/** inclusion flag for lo */
|
2496 |
|
|
private final boolean loInclusive;
|
2497 |
|
|
/** inclusion flag for hi */
|
2498 |
|
|
private final boolean hiInclusive;
|
2499 |
|
|
/** direction */
|
2500 |
|
|
private final boolean isDescending;
|
2501 |
|
|
|
2502 |
|
|
// Lazily initialized view holders
|
2503 |
|
|
private transient KeySet<K> keySetView;
|
2504 |
|
|
private transient Set<Map.Entry<K,V>> entrySetView;
|
2505 |
|
|
private transient Collection<V> valuesView;
|
2506 |
|
|
|
2507 |
|
|
/**
|
2508 |
|
|
* Creates a new submap, initializing all fields
|
2509 |
|
|
*/
|
2510 |
|
|
SubMap(ConcurrentSkipListMap<K,V> map,
|
2511 |
|
|
K fromKey, boolean fromInclusive,
|
2512 |
|
|
K toKey, boolean toInclusive,
|
2513 |
|
|
boolean isDescending) {
|
2514 |
|
|
if (fromKey != null && toKey != null &&
|
2515 |
|
|
map.compare(fromKey, toKey) > 0)
|
2516 |
|
|
throw new IllegalArgumentException("inconsistent range");
|
2517 |
|
|
this.m = map;
|
2518 |
|
|
this.lo = fromKey;
|
2519 |
|
|
this.hi = toKey;
|
2520 |
|
|
this.loInclusive = fromInclusive;
|
2521 |
|
|
this.hiInclusive = toInclusive;
|
2522 |
|
|
this.isDescending = isDescending;
|
2523 |
|
|
}
|
2524 |
|
|
|
2525 |
|
|
/* ---------------- Utilities -------------- */
|
2526 |
|
|
|
2527 |
|
|
private boolean tooLow(K key) {
|
2528 |
|
|
if (lo != null) {
|
2529 |
|
|
int c = m.compare(key, lo);
|
2530 |
|
|
if (c < 0 || (c == 0 && !loInclusive))
|
2531 |
|
|
return true;
|
2532 |
|
|
}
|
2533 |
|
|
return false;
|
2534 |
|
|
}
|
2535 |
|
|
|
2536 |
|
|
private boolean tooHigh(K key) {
|
2537 |
|
|
if (hi != null) {
|
2538 |
|
|
int c = m.compare(key, hi);
|
2539 |
|
|
if (c > 0 || (c == 0 && !hiInclusive))
|
2540 |
|
|
return true;
|
2541 |
|
|
}
|
2542 |
|
|
return false;
|
2543 |
|
|
}
|
2544 |
|
|
|
2545 |
|
|
private boolean inBounds(K key) {
|
2546 |
|
|
return !tooLow(key) && !tooHigh(key);
|
2547 |
|
|
}
|
2548 |
|
|
|
2549 |
|
|
private void checkKeyBounds(K key) throws IllegalArgumentException {
|
2550 |
|
|
if (key == null)
|
2551 |
|
|
throw new NullPointerException();
|
2552 |
|
|
if (!inBounds(key))
|
2553 |
|
|
throw new IllegalArgumentException("key out of range");
|
2554 |
|
|
}
|
2555 |
|
|
|
2556 |
|
|
/**
|
2557 |
|
|
* Returns true if node key is less than upper bound of range
|
2558 |
|
|
*/
|
2559 |
|
|
private boolean isBeforeEnd(ConcurrentSkipListMap.Node<K,V> n) {
|
2560 |
|
|
if (n == null)
|
2561 |
|
|
return false;
|
2562 |
|
|
if (hi == null)
|
2563 |
|
|
return true;
|
2564 |
|
|
K k = n.key;
|
2565 |
|
|
if (k == null) // pass by markers and headers
|
2566 |
|
|
return true;
|
2567 |
|
|
int c = m.compare(k, hi);
|
2568 |
|
|
if (c > 0 || (c == 0 && !hiInclusive))
|
2569 |
|
|
return false;
|
2570 |
|
|
return true;
|
2571 |
|
|
}
|
2572 |
|
|
|
2573 |
|
|
/**
|
2574 |
|
|
* Returns lowest node. This node might not be in range, so
|
2575 |
|
|
* most usages need to check bounds
|
2576 |
|
|
*/
|
2577 |
|
|
private ConcurrentSkipListMap.Node<K,V> loNode() {
|
2578 |
|
|
if (lo == null)
|
2579 |
|
|
return m.findFirst();
|
2580 |
|
|
else if (loInclusive)
|
2581 |
|
|
return m.findNear(lo, m.GT|m.EQ);
|
2582 |
|
|
else
|
2583 |
|
|
return m.findNear(lo, m.GT);
|
2584 |
|
|
}
|
2585 |
|
|
|
2586 |
|
|
/**
|
2587 |
|
|
* Returns highest node. This node might not be in range, so
|
2588 |
|
|
* most usages need to check bounds
|
2589 |
|
|
*/
|
2590 |
|
|
private ConcurrentSkipListMap.Node<K,V> hiNode() {
|
2591 |
|
|
if (hi == null)
|
2592 |
|
|
return m.findLast();
|
2593 |
|
|
else if (hiInclusive)
|
2594 |
|
|
return m.findNear(hi, m.LT|m.EQ);
|
2595 |
|
|
else
|
2596 |
|
|
return m.findNear(hi, m.LT);
|
2597 |
|
|
}
|
2598 |
|
|
|
2599 |
|
|
/**
|
2600 |
|
|
* Returns lowest absolute key (ignoring directonality)
|
2601 |
|
|
*/
|
2602 |
|
|
private K lowestKey() {
|
2603 |
|
|
ConcurrentSkipListMap.Node<K,V> n = loNode();
|
2604 |
|
|
if (isBeforeEnd(n))
|
2605 |
|
|
return n.key;
|
2606 |
|
|
else
|
2607 |
|
|
throw new NoSuchElementException();
|
2608 |
|
|
}
|
2609 |
|
|
|
2610 |
|
|
/**
|
2611 |
|
|
* Returns highest absolute key (ignoring directonality)
|
2612 |
|
|
*/
|
2613 |
|
|
private K highestKey() {
|
2614 |
|
|
ConcurrentSkipListMap.Node<K,V> n = hiNode();
|
2615 |
|
|
if (n != null) {
|
2616 |
|
|
K last = n.key;
|
2617 |
|
|
if (inBounds(last))
|
2618 |
|
|
return last;
|
2619 |
|
|
}
|
2620 |
|
|
throw new NoSuchElementException();
|
2621 |
|
|
}
|
2622 |
|
|
|
2623 |
|
|
private Map.Entry<K,V> lowestEntry() {
|
2624 |
|
|
for (;;) {
|
2625 |
|
|
ConcurrentSkipListMap.Node<K,V> n = loNode();
|
2626 |
|
|
if (!isBeforeEnd(n))
|
2627 |
|
|
return null;
|
2628 |
|
|
Map.Entry<K,V> e = n.createSnapshot();
|
2629 |
|
|
if (e != null)
|
2630 |
|
|
return e;
|
2631 |
|
|
}
|
2632 |
|
|
}
|
2633 |
|
|
|
2634 |
|
|
private Map.Entry<K,V> highestEntry() {
|
2635 |
|
|
for (;;) {
|
2636 |
|
|
ConcurrentSkipListMap.Node<K,V> n = hiNode();
|
2637 |
|
|
if (n == null || !inBounds(n.key))
|
2638 |
|
|
return null;
|
2639 |
|
|
Map.Entry<K,V> e = n.createSnapshot();
|
2640 |
|
|
if (e != null)
|
2641 |
|
|
return e;
|
2642 |
|
|
}
|
2643 |
|
|
}
|
2644 |
|
|
|
2645 |
|
|
private Map.Entry<K,V> removeLowest() {
|
2646 |
|
|
for (;;) {
|
2647 |
|
|
Node<K,V> n = loNode();
|
2648 |
|
|
if (n == null)
|
2649 |
|
|
return null;
|
2650 |
|
|
K k = n.key;
|
2651 |
|
|
if (!inBounds(k))
|
2652 |
|
|
return null;
|
2653 |
|
|
V v = m.doRemove(k, null);
|
2654 |
|
|
if (v != null)
|
2655 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(k, v);
|
2656 |
|
|
}
|
2657 |
|
|
}
|
2658 |
|
|
|
2659 |
|
|
private Map.Entry<K,V> removeHighest() {
|
2660 |
|
|
for (;;) {
|
2661 |
|
|
Node<K,V> n = hiNode();
|
2662 |
|
|
if (n == null)
|
2663 |
|
|
return null;
|
2664 |
|
|
K k = n.key;
|
2665 |
|
|
if (!inBounds(k))
|
2666 |
|
|
return null;
|
2667 |
|
|
V v = m.doRemove(k, null);
|
2668 |
|
|
if (v != null)
|
2669 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(k, v);
|
2670 |
|
|
}
|
2671 |
|
|
}
|
2672 |
|
|
|
2673 |
|
|
/**
|
2674 |
|
|
* Submap version of ConcurrentSkipListMap.getNearEntry
|
2675 |
|
|
*/
|
2676 |
|
|
private Map.Entry<K,V> getNearEntry(K key, int rel) {
|
2677 |
|
|
if (isDescending) { // adjust relation for direction
|
2678 |
|
|
if ((rel & m.LT) == 0)
|
2679 |
|
|
rel |= m.LT;
|
2680 |
|
|
else
|
2681 |
|
|
rel &= ~m.LT;
|
2682 |
|
|
}
|
2683 |
|
|
if (tooLow(key))
|
2684 |
|
|
return ((rel & m.LT) != 0)? null : lowestEntry();
|
2685 |
|
|
if (tooHigh(key))
|
2686 |
|
|
return ((rel & m.LT) != 0)? highestEntry() : null;
|
2687 |
|
|
for (;;) {
|
2688 |
|
|
Node<K,V> n = m.findNear(key, rel);
|
2689 |
|
|
if (n == null || !inBounds(n.key))
|
2690 |
|
|
return null;
|
2691 |
|
|
K k = n.key;
|
2692 |
|
|
V v = n.getValidValue();
|
2693 |
|
|
if (v != null)
|
2694 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(k, v);
|
2695 |
|
|
}
|
2696 |
|
|
}
|
2697 |
|
|
|
2698 |
|
|
// Almost the same as getNearEntry, except for keys
|
2699 |
|
|
private K getNearKey(K key, int rel) {
|
2700 |
|
|
if (isDescending) { // adjust relation for direction
|
2701 |
|
|
if ((rel & m.LT) == 0)
|
2702 |
|
|
rel |= m.LT;
|
2703 |
|
|
else
|
2704 |
|
|
rel &= ~m.LT;
|
2705 |
|
|
}
|
2706 |
|
|
if (tooLow(key)) {
|
2707 |
|
|
if ((rel & m.LT) == 0) {
|
2708 |
|
|
ConcurrentSkipListMap.Node<K,V> n = loNode();
|
2709 |
|
|
if (isBeforeEnd(n))
|
2710 |
|
|
return n.key;
|
2711 |
|
|
}
|
2712 |
|
|
return null;
|
2713 |
|
|
}
|
2714 |
|
|
if (tooHigh(key)) {
|
2715 |
|
|
if ((rel & m.LT) != 0) {
|
2716 |
|
|
ConcurrentSkipListMap.Node<K,V> n = hiNode();
|
2717 |
|
|
if (n != null) {
|
2718 |
|
|
K last = n.key;
|
2719 |
|
|
if (inBounds(last))
|
2720 |
|
|
return last;
|
2721 |
|
|
}
|
2722 |
|
|
}
|
2723 |
|
|
return null;
|
2724 |
|
|
}
|
2725 |
|
|
for (;;) {
|
2726 |
|
|
Node<K,V> n = m.findNear(key, rel);
|
2727 |
|
|
if (n == null || !inBounds(n.key))
|
2728 |
|
|
return null;
|
2729 |
|
|
K k = n.key;
|
2730 |
|
|
V v = n.getValidValue();
|
2731 |
|
|
if (v != null)
|
2732 |
|
|
return k;
|
2733 |
|
|
}
|
2734 |
|
|
}
|
2735 |
|
|
|
2736 |
|
|
/* ---------------- Map API methods -------------- */
|
2737 |
|
|
|
2738 |
|
|
public boolean containsKey(Object key) {
|
2739 |
|
|
if (key == null) throw new NullPointerException();
|
2740 |
|
|
K k = (K)key;
|
2741 |
|
|
return inBounds(k) && m.containsKey(k);
|
2742 |
|
|
}
|
2743 |
|
|
|
2744 |
|
|
public V get(Object key) {
|
2745 |
|
|
if (key == null) throw new NullPointerException();
|
2746 |
|
|
K k = (K)key;
|
2747 |
|
|
return ((!inBounds(k)) ? null : m.get(k));
|
2748 |
|
|
}
|
2749 |
|
|
|
2750 |
|
|
public V put(K key, V value) {
|
2751 |
|
|
checkKeyBounds(key);
|
2752 |
|
|
return m.put(key, value);
|
2753 |
|
|
}
|
2754 |
|
|
|
2755 |
|
|
public V remove(Object key) {
|
2756 |
|
|
K k = (K)key;
|
2757 |
|
|
return (!inBounds(k))? null : m.remove(k);
|
2758 |
|
|
}
|
2759 |
|
|
|
2760 |
|
|
public int size() {
|
2761 |
|
|
long count = 0;
|
2762 |
|
|
for (ConcurrentSkipListMap.Node<K,V> n = loNode();
|
2763 |
|
|
isBeforeEnd(n);
|
2764 |
|
|
n = n.next) {
|
2765 |
|
|
if (n.getValidValue() != null)
|
2766 |
|
|
++count;
|
2767 |
|
|
}
|
2768 |
|
|
return count >= Integer.MAX_VALUE? Integer.MAX_VALUE : (int)count;
|
2769 |
|
|
}
|
2770 |
|
|
|
2771 |
|
|
public boolean isEmpty() {
|
2772 |
|
|
return !isBeforeEnd(loNode());
|
2773 |
|
|
}
|
2774 |
|
|
|
2775 |
|
|
public boolean containsValue(Object value) {
|
2776 |
|
|
if (value == null)
|
2777 |
|
|
throw new NullPointerException();
|
2778 |
|
|
for (ConcurrentSkipListMap.Node<K,V> n = loNode();
|
2779 |
|
|
isBeforeEnd(n);
|
2780 |
|
|
n = n.next) {
|
2781 |
|
|
V v = n.getValidValue();
|
2782 |
|
|
if (v != null && value.equals(v))
|
2783 |
|
|
return true;
|
2784 |
|
|
}
|
2785 |
|
|
return false;
|
2786 |
|
|
}
|
2787 |
|
|
|
2788 |
|
|
public void clear() {
|
2789 |
|
|
for (ConcurrentSkipListMap.Node<K,V> n = loNode();
|
2790 |
|
|
isBeforeEnd(n);
|
2791 |
|
|
n = n.next) {
|
2792 |
|
|
if (n.getValidValue() != null)
|
2793 |
|
|
m.remove(n.key);
|
2794 |
|
|
}
|
2795 |
|
|
}
|
2796 |
|
|
|
2797 |
|
|
/* ---------------- ConcurrentMap API methods -------------- */
|
2798 |
|
|
|
2799 |
|
|
public V putIfAbsent(K key, V value) {
|
2800 |
|
|
checkKeyBounds(key);
|
2801 |
|
|
return m.putIfAbsent(key, value);
|
2802 |
|
|
}
|
2803 |
|
|
|
2804 |
|
|
public boolean remove(Object key, Object value) {
|
2805 |
|
|
K k = (K)key;
|
2806 |
|
|
return inBounds(k) && m.remove(k, value);
|
2807 |
|
|
}
|
2808 |
|
|
|
2809 |
|
|
public boolean replace(K key, V oldValue, V newValue) {
|
2810 |
|
|
checkKeyBounds(key);
|
2811 |
|
|
return m.replace(key, oldValue, newValue);
|
2812 |
|
|
}
|
2813 |
|
|
|
2814 |
|
|
public V replace(K key, V value) {
|
2815 |
|
|
checkKeyBounds(key);
|
2816 |
|
|
return m.replace(key, value);
|
2817 |
|
|
}
|
2818 |
|
|
|
2819 |
|
|
/* ---------------- SortedMap API methods -------------- */
|
2820 |
|
|
|
2821 |
|
|
public Comparator<? super K> comparator() {
|
2822 |
|
|
Comparator<? super K> cmp = m.comparator();
|
2823 |
|
|
if (isDescending)
|
2824 |
|
|
return Collections.reverseOrder(cmp);
|
2825 |
|
|
else
|
2826 |
|
|
return cmp;
|
2827 |
|
|
}
|
2828 |
|
|
|
2829 |
|
|
/**
|
2830 |
|
|
* Utility to create submaps, where given bounds override
|
2831 |
|
|
* unbounded(null) ones and/or are checked against bounded ones.
|
2832 |
|
|
*/
|
2833 |
|
|
private SubMap<K,V> newSubMap(K fromKey,
|
2834 |
|
|
boolean fromInclusive,
|
2835 |
|
|
K toKey,
|
2836 |
|
|
boolean toInclusive) {
|
2837 |
|
|
if (isDescending) { // flip senses
|
2838 |
|
|
K tk = fromKey;
|
2839 |
|
|
fromKey = toKey;
|
2840 |
|
|
toKey = tk;
|
2841 |
|
|
boolean ti = fromInclusive;
|
2842 |
|
|
fromInclusive = toInclusive;
|
2843 |
|
|
toInclusive = ti;
|
2844 |
|
|
}
|
2845 |
|
|
if (lo != null) {
|
2846 |
|
|
if (fromKey == null) {
|
2847 |
|
|
fromKey = lo;
|
2848 |
|
|
fromInclusive = loInclusive;
|
2849 |
|
|
}
|
2850 |
|
|
else {
|
2851 |
|
|
int c = m.compare(fromKey, lo);
|
2852 |
|
|
if (c < 0 || (c == 0 && !loInclusive && fromInclusive))
|
2853 |
|
|
throw new IllegalArgumentException("key out of range");
|
2854 |
|
|
}
|
2855 |
|
|
}
|
2856 |
|
|
if (hi != null) {
|
2857 |
|
|
if (toKey == null) {
|
2858 |
|
|
toKey = hi;
|
2859 |
|
|
toInclusive = hiInclusive;
|
2860 |
|
|
}
|
2861 |
|
|
else {
|
2862 |
|
|
int c = m.compare(toKey, hi);
|
2863 |
|
|
if (c > 0 || (c == 0 && !hiInclusive && toInclusive))
|
2864 |
|
|
throw new IllegalArgumentException("key out of range");
|
2865 |
|
|
}
|
2866 |
|
|
}
|
2867 |
|
|
return new SubMap<K,V>(m, fromKey, fromInclusive,
|
2868 |
|
|
toKey, toInclusive, isDescending);
|
2869 |
|
|
}
|
2870 |
|
|
|
2871 |
|
|
public SubMap<K,V> subMap(K fromKey,
|
2872 |
|
|
boolean fromInclusive,
|
2873 |
|
|
K toKey,
|
2874 |
|
|
boolean toInclusive) {
|
2875 |
|
|
if (fromKey == null || toKey == null)
|
2876 |
|
|
throw new NullPointerException();
|
2877 |
|
|
return newSubMap(fromKey, fromInclusive, toKey, toInclusive);
|
2878 |
|
|
}
|
2879 |
|
|
|
2880 |
|
|
public SubMap<K,V> headMap(K toKey,
|
2881 |
|
|
boolean inclusive) {
|
2882 |
|
|
if (toKey == null)
|
2883 |
|
|
throw new NullPointerException();
|
2884 |
|
|
return newSubMap(null, false, toKey, inclusive);
|
2885 |
|
|
}
|
2886 |
|
|
|
2887 |
|
|
public SubMap<K,V> tailMap(K fromKey,
|
2888 |
|
|
boolean inclusive) {
|
2889 |
|
|
if (fromKey == null)
|
2890 |
|
|
throw new NullPointerException();
|
2891 |
|
|
return newSubMap(fromKey, inclusive, null, false);
|
2892 |
|
|
}
|
2893 |
|
|
|
2894 |
|
|
public SubMap<K,V> subMap(K fromKey, K toKey) {
|
2895 |
|
|
return subMap(fromKey, true, toKey, false);
|
2896 |
|
|
}
|
2897 |
|
|
|
2898 |
|
|
public SubMap<K,V> headMap(K toKey) {
|
2899 |
|
|
return headMap(toKey, false);
|
2900 |
|
|
}
|
2901 |
|
|
|
2902 |
|
|
public SubMap<K,V> tailMap(K fromKey) {
|
2903 |
|
|
return tailMap(fromKey, true);
|
2904 |
|
|
}
|
2905 |
|
|
|
2906 |
|
|
public SubMap<K,V> descendingMap() {
|
2907 |
|
|
return new SubMap<K,V>(m, lo, loInclusive,
|
2908 |
|
|
hi, hiInclusive, !isDescending);
|
2909 |
|
|
}
|
2910 |
|
|
|
2911 |
|
|
/* ---------------- Relational methods -------------- */
|
2912 |
|
|
|
2913 |
|
|
public Map.Entry<K,V> ceilingEntry(K key) {
|
2914 |
|
|
return getNearEntry(key, (m.GT|m.EQ));
|
2915 |
|
|
}
|
2916 |
|
|
|
2917 |
|
|
public K ceilingKey(K key) {
|
2918 |
|
|
return getNearKey(key, (m.GT|m.EQ));
|
2919 |
|
|
}
|
2920 |
|
|
|
2921 |
|
|
public Map.Entry<K,V> lowerEntry(K key) {
|
2922 |
|
|
return getNearEntry(key, (m.LT));
|
2923 |
|
|
}
|
2924 |
|
|
|
2925 |
|
|
public K lowerKey(K key) {
|
2926 |
|
|
return getNearKey(key, (m.LT));
|
2927 |
|
|
}
|
2928 |
|
|
|
2929 |
|
|
public Map.Entry<K,V> floorEntry(K key) {
|
2930 |
|
|
return getNearEntry(key, (m.LT|m.EQ));
|
2931 |
|
|
}
|
2932 |
|
|
|
2933 |
|
|
public K floorKey(K key) {
|
2934 |
|
|
return getNearKey(key, (m.LT|m.EQ));
|
2935 |
|
|
}
|
2936 |
|
|
|
2937 |
|
|
public Map.Entry<K,V> higherEntry(K key) {
|
2938 |
|
|
return getNearEntry(key, (m.GT));
|
2939 |
|
|
}
|
2940 |
|
|
|
2941 |
|
|
public K higherKey(K key) {
|
2942 |
|
|
return getNearKey(key, (m.GT));
|
2943 |
|
|
}
|
2944 |
|
|
|
2945 |
|
|
public K firstKey() {
|
2946 |
|
|
return isDescending? highestKey() : lowestKey();
|
2947 |
|
|
}
|
2948 |
|
|
|
2949 |
|
|
public K lastKey() {
|
2950 |
|
|
return isDescending? lowestKey() : highestKey();
|
2951 |
|
|
}
|
2952 |
|
|
|
2953 |
|
|
public Map.Entry<K,V> firstEntry() {
|
2954 |
|
|
return isDescending? highestEntry() : lowestEntry();
|
2955 |
|
|
}
|
2956 |
|
|
|
2957 |
|
|
public Map.Entry<K,V> lastEntry() {
|
2958 |
|
|
return isDescending? lowestEntry() : highestEntry();
|
2959 |
|
|
}
|
2960 |
|
|
|
2961 |
|
|
public Map.Entry<K,V> pollFirstEntry() {
|
2962 |
|
|
return isDescending? removeHighest() : removeLowest();
|
2963 |
|
|
}
|
2964 |
|
|
|
2965 |
|
|
public Map.Entry<K,V> pollLastEntry() {
|
2966 |
|
|
return isDescending? removeLowest() : removeHighest();
|
2967 |
|
|
}
|
2968 |
|
|
|
2969 |
|
|
/* ---------------- Submap Views -------------- */
|
2970 |
|
|
|
2971 |
|
|
public NavigableSet<K> keySet() {
|
2972 |
|
|
KeySet<K> ks = keySetView;
|
2973 |
|
|
return (ks != null) ? ks : (keySetView = new KeySet(this));
|
2974 |
|
|
}
|
2975 |
|
|
|
2976 |
|
|
public NavigableSet<K> navigableKeySet() {
|
2977 |
|
|
KeySet<K> ks = keySetView;
|
2978 |
|
|
return (ks != null) ? ks : (keySetView = new KeySet(this));
|
2979 |
|
|
}
|
2980 |
|
|
|
2981 |
|
|
public Collection<V> values() {
|
2982 |
|
|
Collection<V> vs = valuesView;
|
2983 |
|
|
return (vs != null) ? vs : (valuesView = new Values(this));
|
2984 |
|
|
}
|
2985 |
|
|
|
2986 |
|
|
public Set<Map.Entry<K,V>> entrySet() {
|
2987 |
|
|
Set<Map.Entry<K,V>> es = entrySetView;
|
2988 |
|
|
return (es != null) ? es : (entrySetView = new EntrySet(this));
|
2989 |
|
|
}
|
2990 |
|
|
|
2991 |
|
|
public NavigableSet<K> descendingKeySet() {
|
2992 |
|
|
return descendingMap().navigableKeySet();
|
2993 |
|
|
}
|
2994 |
|
|
|
2995 |
|
|
Iterator<K> keyIterator() {
|
2996 |
|
|
return new SubMapKeyIterator();
|
2997 |
|
|
}
|
2998 |
|
|
|
2999 |
|
|
Iterator<V> valueIterator() {
|
3000 |
|
|
return new SubMapValueIterator();
|
3001 |
|
|
}
|
3002 |
|
|
|
3003 |
|
|
Iterator<Map.Entry<K,V>> entryIterator() {
|
3004 |
|
|
return new SubMapEntryIterator();
|
3005 |
|
|
}
|
3006 |
|
|
|
3007 |
|
|
/**
|
3008 |
|
|
* Variant of main Iter class to traverse through submaps.
|
3009 |
|
|
*/
|
3010 |
|
|
abstract class SubMapIter<T> implements Iterator<T> {
|
3011 |
|
|
/** the last node returned by next() */
|
3012 |
|
|
Node<K,V> lastReturned;
|
3013 |
|
|
/** the next node to return from next(); */
|
3014 |
|
|
Node<K,V> next;
|
3015 |
|
|
/** Cache of next value field to maintain weak consistency */
|
3016 |
|
|
V nextValue;
|
3017 |
|
|
|
3018 |
|
|
SubMapIter() {
|
3019 |
|
|
for (;;) {
|
3020 |
|
|
next = isDescending ? hiNode() : loNode();
|
3021 |
|
|
if (next == null)
|
3022 |
|
|
break;
|
3023 |
|
|
Object x = next.value;
|
3024 |
|
|
if (x != null && x != next) {
|
3025 |
|
|
if (! inBounds(next.key))
|
3026 |
|
|
next = null;
|
3027 |
|
|
else
|
3028 |
|
|
nextValue = (V) x;
|
3029 |
|
|
break;
|
3030 |
|
|
}
|
3031 |
|
|
}
|
3032 |
|
|
}
|
3033 |
|
|
|
3034 |
|
|
public final boolean hasNext() {
|
3035 |
|
|
return next != null;
|
3036 |
|
|
}
|
3037 |
|
|
|
3038 |
|
|
final void advance() {
|
3039 |
|
|
if ((lastReturned = next) == null)
|
3040 |
|
|
throw new NoSuchElementException();
|
3041 |
|
|
if (isDescending)
|
3042 |
|
|
descend();
|
3043 |
|
|
else
|
3044 |
|
|
ascend();
|
3045 |
|
|
}
|
3046 |
|
|
|
3047 |
|
|
private void ascend() {
|
3048 |
|
|
for (;;) {
|
3049 |
|
|
next = next.next;
|
3050 |
|
|
if (next == null)
|
3051 |
|
|
break;
|
3052 |
|
|
Object x = next.value;
|
3053 |
|
|
if (x != null && x != next) {
|
3054 |
|
|
if (tooHigh(next.key))
|
3055 |
|
|
next = null;
|
3056 |
|
|
else
|
3057 |
|
|
nextValue = (V) x;
|
3058 |
|
|
break;
|
3059 |
|
|
}
|
3060 |
|
|
}
|
3061 |
|
|
}
|
3062 |
|
|
|
3063 |
|
|
private void descend() {
|
3064 |
|
|
for (;;) {
|
3065 |
|
|
next = m.findNear(lastReturned.key, LT);
|
3066 |
|
|
if (next == null)
|
3067 |
|
|
break;
|
3068 |
|
|
Object x = next.value;
|
3069 |
|
|
if (x != null && x != next) {
|
3070 |
|
|
if (tooLow(next.key))
|
3071 |
|
|
next = null;
|
3072 |
|
|
else
|
3073 |
|
|
nextValue = (V) x;
|
3074 |
|
|
break;
|
3075 |
|
|
}
|
3076 |
|
|
}
|
3077 |
|
|
}
|
3078 |
|
|
|
3079 |
|
|
public void remove() {
|
3080 |
|
|
Node<K,V> l = lastReturned;
|
3081 |
|
|
if (l == null)
|
3082 |
|
|
throw new IllegalStateException();
|
3083 |
|
|
m.remove(l.key);
|
3084 |
|
|
lastReturned = null;
|
3085 |
|
|
}
|
3086 |
|
|
|
3087 |
|
|
}
|
3088 |
|
|
|
3089 |
|
|
final class SubMapValueIterator extends SubMapIter<V> {
|
3090 |
|
|
public V next() {
|
3091 |
|
|
V v = nextValue;
|
3092 |
|
|
advance();
|
3093 |
|
|
return v;
|
3094 |
|
|
}
|
3095 |
|
|
}
|
3096 |
|
|
|
3097 |
|
|
final class SubMapKeyIterator extends SubMapIter<K> {
|
3098 |
|
|
public K next() {
|
3099 |
|
|
Node<K,V> n = next;
|
3100 |
|
|
advance();
|
3101 |
|
|
return n.key;
|
3102 |
|
|
}
|
3103 |
|
|
}
|
3104 |
|
|
|
3105 |
|
|
final class SubMapEntryIterator extends SubMapIter<Map.Entry<K,V>> {
|
3106 |
|
|
public Map.Entry<K,V> next() {
|
3107 |
|
|
Node<K,V> n = next;
|
3108 |
|
|
V v = nextValue;
|
3109 |
|
|
advance();
|
3110 |
|
|
return new AbstractMap.SimpleImmutableEntry<K,V>(n.key, v);
|
3111 |
|
|
}
|
3112 |
|
|
}
|
3113 |
|
|
}
|
3114 |
|
|
}
|