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jeremybenn |
/* FilterReader.java -- Base class for char stream classes that filter input
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Copyright (C) 1998, 1999, 2001, 2003, 2005 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package java.io;
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/* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
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* "The Java Language Specification", ISBN 0-201-63451-1
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* plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
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* Status: Believed complete and correct.
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*/
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/**
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* This is the common superclass of all standard classes that filter
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* input. It acts as a layer on top of an underlying <code>Reader</code>
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* and simply redirects calls made to it to the subordinate Reader
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* instead. Subclasses of this class perform additional filtering
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* functions in addition to simply redirecting the call.
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* <p>
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* When creating a subclass of <code>FilterReader</code>, override the
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* appropriate methods to implement the desired filtering. However, note
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* that the <code>read(char[])</code> method does not need to be overridden
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* as this class redirects calls to that method to
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* <code>read(yte[], int, int)</code> instead of to the subordinate
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* <code>Reader} read(yte[])</code> method.
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*
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* @author Aaron M. Renn (arenn@urbanophile.com)
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* @author Warren Levy (warrenl@cygnus.com)
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*/
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public abstract class FilterReader extends Reader
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{
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/**
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* This is the subordinate <code>Reader</code> to which method calls
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* are redirected
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*/
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protected Reader in;
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/**
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* Create a <code>FilterReader</code> with the specified subordinate
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* <code>Reader</code>.
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* The <code>lock</code> of the new <code>FilterReader</code> will be set
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* to <code>in.lock</code>.
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*
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* @param in The subordinate <code>Reader</code>
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*/
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protected FilterReader(Reader in)
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{
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super(in.lock);
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this.in = in;
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}
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/**
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* Calls the <code>in.mark(int)</code> method.
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*
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* @param readlimit The parameter passed to <code>in.mark(int)</code>
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*
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* @exception IOException If an error occurs
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*/
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public void mark(int readlimit) throws IOException
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{
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in.mark(readlimit);
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}
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/**
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* Calls the <code>in.markSupported()</code> method.
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*
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* @return <code>true</code> if mark/reset is supported,
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* <code>false</code> otherwise
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*/
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public boolean markSupported()
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{
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return(in.markSupported());
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}
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/**
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* Calls the <code>in.reset()</code> method.
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*
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* @exception IOException If an error occurs
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*/
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public void reset() throws IOException
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{
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in.reset();
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}
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/**
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* Calls the <code>in.read()</code> method.
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*
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* @return The value returned from <code>in.available()</code>
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*
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* @exception IOException If an error occurs
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*/
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public boolean ready() throws IOException
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{
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return(in.ready());
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}
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/**
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* Calls the <code>in.skip(long)</code> method
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*
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* @param num_chars The requested number of chars to skip.
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*
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* @return The value returned from <code>in.skip(long)</code>
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*
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* @exception IOException If an error occurs
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*/
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public long skip(long num_chars) throws IOException
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{
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return(in.skip(num_chars));
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}
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/**
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* Calls the <code>in.read()</code> method
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*
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* @return The value returned from <code>in.read()</code>
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*
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* @exception IOException If an error occurs
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*/
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public int read() throws IOException
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{
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return(in.read());
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}
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/**
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* Calls the <code>in.read(char[], int, int)</code> method.
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*
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* @param buf The buffer to read chars into
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* @param offset The index into the buffer to start storing chars
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* @param len The maximum number of chars to read.
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*
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* @return The value retured from <code>in.read(char[], int, int)</code>
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*
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* @exception IOException If an error occurs
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*/
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public int read(char[] buf, int offset, int len) throws IOException
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{
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return(in.read(buf, offset, len));
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}
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/**
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* This method closes the stream by calling the <code>close()</code> method
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* of the underlying stream.
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*
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* @exception IOException If an error occurs
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*/
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public void close() throws IOException
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{
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in.close();
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}
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} // class FilterReader
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