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jeremybenn |
/* FilterInputStream.java -- Base class for classes that filter input
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Copyright (C) 1998, 1999, 2001, 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>InputStream</code>
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* and simply redirects calls made to it to the subordinate InputStream
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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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* This class is not abstract. However, since it only redirects calls
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* to a subordinate <code>InputStream</code> without adding any functionality
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* on top of it, this class should not be used directly. Instead, various
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* subclasses of this class should be used. This is enforced with a
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* protected constructor. Do not try to hack around it.
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* <p>
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* When creating a subclass of <code>FilterInputStream</code>, override the
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* appropriate methods to implement the desired filtering. However, note
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* that the <code>read(byte[])</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(byte[], int, int)</code> instead of to the subordinate
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* <code>InputStream read(byte[])</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 class FilterInputStream extends InputStream
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{
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/**
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* This is the subordinate <code>InputStream</code> to which method calls
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* are redirected
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*/
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protected InputStream in;
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/**
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* Create a <code>FilterInputStream</code> with the specified subordinate
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* <code>InputStream</code>.
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*
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* @param in The subordinate <code>InputStream</code>
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*/
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protected FilterInputStream(InputStream in)
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{
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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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public void mark(int readlimit)
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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, <code>false</code>
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* 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.available()</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 int available() throws IOException
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{
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return in.available();
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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 numBytes The requested number of bytes 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 numBytes) throws IOException
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{
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return in.skip(numBytes);
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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>read(byte[], int, int)</code> overloaded method.
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* Note that
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* this method does not redirect its call directly to a corresponding
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* method in <code>in</code>. This allows subclasses to override only the
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* three argument version of <code>read</code>.
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*
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* @param buf The buffer to read bytes into
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*
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* @return The value retured from <code>in.read(byte[], 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(byte[] buf) throws IOException
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{
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return read(buf, 0, buf.length);
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}
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/**
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* Calls the <code>in.read(byte[], int, int)</code> method.
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*
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* @param buf The buffer to read bytes into
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* @param offset The index into the buffer to start storing bytes
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* @param len The maximum number of bytes to read.
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*
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* @return The value retured from <code>in.read(byte[], 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(byte[] 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 input stream by closing the input stream that
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* this object is filtering. Future attempts to access this stream may
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* throw an exception.
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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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}
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