1 |
14 |
jlechner |
/* ListIterator.java -- Extended Iterator for iterating over ordered lists
|
2 |
|
|
Copyright (C) 1998, 1999, 2001, 2005 Free Software Foundation, Inc.
|
3 |
|
|
|
4 |
|
|
This file is part of GNU Classpath.
|
5 |
|
|
|
6 |
|
|
GNU Classpath is free software; you can redistribute it and/or modify
|
7 |
|
|
it under the terms of the GNU General Public License as published by
|
8 |
|
|
the Free Software Foundation; either version 2, or (at your option)
|
9 |
|
|
any later version.
|
10 |
|
|
|
11 |
|
|
GNU Classpath is distributed in the hope that it will be useful, but
|
12 |
|
|
WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 |
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
14 |
|
|
General Public License for more details.
|
15 |
|
|
|
16 |
|
|
You should have received a copy of the GNU General Public License
|
17 |
|
|
along with GNU Classpath; see the file COPYING. If not, write to the
|
18 |
|
|
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
|
19 |
|
|
02110-1301 USA.
|
20 |
|
|
|
21 |
|
|
Linking this library statically or dynamically with other modules is
|
22 |
|
|
making a combined work based on this library. Thus, the terms and
|
23 |
|
|
conditions of the GNU General Public License cover the whole
|
24 |
|
|
combination.
|
25 |
|
|
|
26 |
|
|
As a special exception, the copyright holders of this library give you
|
27 |
|
|
permission to link this library with independent modules to produce an
|
28 |
|
|
executable, regardless of the license terms of these independent
|
29 |
|
|
modules, and to copy and distribute the resulting executable under
|
30 |
|
|
terms of your choice, provided that you also meet, for each linked
|
31 |
|
|
independent module, the terms and conditions of the license of that
|
32 |
|
|
module. An independent module is a module which is not derived from
|
33 |
|
|
or based on this library. If you modify this library, you may extend
|
34 |
|
|
this exception to your version of the library, but you are not
|
35 |
|
|
obligated to do so. If you do not wish to do so, delete this
|
36 |
|
|
exception statement from your version. */
|
37 |
|
|
|
38 |
|
|
|
39 |
|
|
package java.util;
|
40 |
|
|
|
41 |
|
|
/**
|
42 |
|
|
* An extended version of Iterator to support the extra features of Lists. The
|
43 |
|
|
* elements may be accessed in forward or reverse order, elements may be
|
44 |
|
|
* replaced as well as removed, and new elements may be inserted, during the
|
45 |
|
|
* traversal of the list.
|
46 |
|
|
* <p>
|
47 |
|
|
*
|
48 |
|
|
* A list with n elements provides n+1 iterator positions (the front, the end,
|
49 |
|
|
* or between two elements). Note that <code>remove</code> and <code>set</code>
|
50 |
|
|
* operate on the last element returned, whether it was by <code>next</code>
|
51 |
|
|
* or <code>previous</code>.
|
52 |
|
|
*
|
53 |
|
|
* @author Original author unknown
|
54 |
|
|
* @author Eric Blake (ebb9@email.byu.edu)
|
55 |
|
|
* @see Collection
|
56 |
|
|
* @see List
|
57 |
|
|
* @see Iterator
|
58 |
|
|
* @see Enumeration
|
59 |
|
|
* @since 1.2
|
60 |
|
|
* @status updated to 1.4
|
61 |
|
|
*/
|
62 |
|
|
public interface ListIterator extends Iterator
|
63 |
|
|
{
|
64 |
|
|
/**
|
65 |
|
|
* Tests whether there are elements remaining in the list in the forward
|
66 |
|
|
* direction. In other words, next() will not fail with a
|
67 |
|
|
* NoSuchElementException.
|
68 |
|
|
*
|
69 |
|
|
* @return true if the list continues in the forward direction
|
70 |
|
|
*/
|
71 |
|
|
boolean hasNext();
|
72 |
|
|
|
73 |
|
|
/**
|
74 |
|
|
* Tests whether there are elements remaining in the list in the reverse
|
75 |
|
|
* direction. In other words, previous() will not fail with a
|
76 |
|
|
* NoSuchElementException.
|
77 |
|
|
*
|
78 |
|
|
* @return true if the list continues in the reverse direction
|
79 |
|
|
*/
|
80 |
|
|
boolean hasPrevious();
|
81 |
|
|
|
82 |
|
|
/**
|
83 |
|
|
* Obtain the next element in the list in the forward direction. Repeated
|
84 |
|
|
* calls to next may be used to iterate over the entire list, or calls to
|
85 |
|
|
* next and previous may be used together to go forwards and backwards.
|
86 |
|
|
* Alternating calls to next and previous will return the same element.
|
87 |
|
|
*
|
88 |
|
|
* @return the next element in the list in the forward direction
|
89 |
|
|
* @throws NoSuchElementException if there are no more elements
|
90 |
|
|
*/
|
91 |
|
|
Object next();
|
92 |
|
|
|
93 |
|
|
/**
|
94 |
|
|
* Obtain the next element in the list in the reverse direction. Repeated
|
95 |
|
|
* calls to previous may be used to iterate backwards over the entire list,
|
96 |
|
|
* or calls to next and previous may be used together to go forwards and
|
97 |
|
|
* backwards. Alternating calls to next and previous will return the same
|
98 |
|
|
* element.
|
99 |
|
|
*
|
100 |
|
|
* @return the next element in the list in the reverse direction
|
101 |
|
|
* @throws NoSuchElementException if there are no more elements
|
102 |
|
|
*/
|
103 |
|
|
Object previous();
|
104 |
|
|
|
105 |
|
|
/**
|
106 |
|
|
* Find the index of the element that would be returned by a call to next.
|
107 |
|
|
* If hasNext() returns false, this returns the list size.
|
108 |
|
|
*
|
109 |
|
|
* @return the index of the element that would be returned by next()
|
110 |
|
|
*/
|
111 |
|
|
int nextIndex();
|
112 |
|
|
|
113 |
|
|
/**
|
114 |
|
|
* Find the index of the element that would be returned by a call to
|
115 |
|
|
* previous. If hasPrevious() returns false, this returns -1.
|
116 |
|
|
*
|
117 |
|
|
* @return the index of the element that would be returned by previous()
|
118 |
|
|
*/
|
119 |
|
|
int previousIndex();
|
120 |
|
|
|
121 |
|
|
/**
|
122 |
|
|
* Insert an element into the list at the current position of the iterator
|
123 |
|
|
* (optional operation). The element is inserted in between the element that
|
124 |
|
|
* would be returned by previous and the element that would be returned by
|
125 |
|
|
* next. After the insertion, a subsequent call to next is unaffected, but
|
126 |
|
|
* a call to previous returns the item that was added. The values returned
|
127 |
|
|
* by nextIndex() and previousIndex() are incremented.
|
128 |
|
|
*
|
129 |
|
|
* @param o the object to insert into the list
|
130 |
|
|
* @throws ClassCastException if the object is of a type which cannot be added
|
131 |
|
|
* to this list.
|
132 |
|
|
* @throws IllegalArgumentException if some other aspect of the object stops
|
133 |
|
|
* it being added to this list.
|
134 |
|
|
* @throws UnsupportedOperationException if this ListIterator does not
|
135 |
|
|
* support the add operation.
|
136 |
|
|
*/
|
137 |
|
|
void add(Object o);
|
138 |
|
|
|
139 |
|
|
/**
|
140 |
|
|
* Remove from the list the element last returned by a call to next or
|
141 |
|
|
* previous (optional operation). This method may only be called if neither
|
142 |
|
|
* add nor remove have been called since the last call to next or previous.
|
143 |
|
|
*
|
144 |
|
|
* @throws IllegalStateException if neither next or previous have been
|
145 |
|
|
* called, or if add or remove has been called since the last call
|
146 |
|
|
* to next or previous
|
147 |
|
|
* @throws UnsupportedOperationException if this ListIterator does not
|
148 |
|
|
* support the remove operation
|
149 |
|
|
*/
|
150 |
|
|
void remove();
|
151 |
|
|
|
152 |
|
|
/**
|
153 |
|
|
* Replace the element last returned by a call to next or previous with a
|
154 |
|
|
* given object (optional operation). This method may only be called if
|
155 |
|
|
* neither add nor remove have been called since the last call to next or
|
156 |
|
|
* previous.
|
157 |
|
|
*
|
158 |
|
|
* @param o the object to replace the element with
|
159 |
|
|
* @throws ClassCastException the object is of a type which cannot be added
|
160 |
|
|
* to this list
|
161 |
|
|
* @throws IllegalArgumentException some other aspect of the object stops
|
162 |
|
|
* it being added to this list
|
163 |
|
|
* @throws IllegalStateException if neither next or previous have been
|
164 |
|
|
* called, or if add or remove has been called since the last call
|
165 |
|
|
* to next or previous
|
166 |
|
|
* @throws UnsupportedOperationException if this ListIterator does not
|
167 |
|
|
* support the set operation
|
168 |
|
|
*/
|
169 |
|
|
void set(Object o);
|
170 |
|
|
}
|