1 /* FilterInputStream.java -- Base class for classes that filter input
2 Copyright (C) 1998, 1999, 2001, 2005 Free Software Foundation, Inc.
4 This file is part of GNU Classpath.
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)
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.
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
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
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. */
40 /* Written using "Java Class Libraries", 2nd edition, ISBN 0-201-31002-3
41 * "The Java Language Specification", ISBN 0-201-63451-1
42 * plus online API docs for JDK 1.2 beta from http://www.javasoft.com.
43 * Status: Believed complete and correct.
47 * This is the common superclass of all standard classes that filter input. It
48 * acts as a layer on top of an underlying <code>InputStream</code> and simply
49 * redirects calls made to it to the subordinate InputStream instead. Subclasses
50 * of this class perform additional filtering functions in addition to simply
51 * redirecting the call.
53 * This class is not abstract. However, since it only redirects calls to a
54 * subordinate <code>InputStream</code> without adding any functionality on top
55 * of it, this class should not be used directly. Instead, various subclasses of
56 * this class should be used. This is enforced with a protected constructor. Do
57 * not try to hack around it.
59 * When creating a subclass of <code>FilterInputStream</code>, override the
60 * appropriate methods to implement the desired filtering. However, note that
61 * the <code>read(byte[])</code> method does not need to be overridden as this
62 * class redirects calls to that method to <code>read(byte[], int, int)</code>
63 * instead of to the subordinate <code>InputStream read(byte[])</code> method.
65 * @author Aaron M. Renn (arenn@urbanophile.com)
66 * @author Warren Levy (warrenl@cygnus.com)
69 public class FilterInputStream extends InputStream {
71 * This is the subordinate <code>InputStream</code> to which method calls are
74 protected InputStream in;
77 * Create a <code>FilterInputStream</code> with the specified subordinate
78 * <code>InputStream</code>.
81 * The subordinate <code>InputStream</code>
83 protected FilterInputStream(InputStream in) {
88 * Calls the <code>in.mark(int)</code> method.
91 * The parameter passed to <code>in.mark(int)</code>
93 public void mark(int readlimit) {
98 * Calls the <code>in.markSupported()</code> method.
100 * @return <code>true</code> if mark/reset is supported, <code>false</code>
104 public boolean markSupported() {
105 return in.markSupported();
109 * Calls the <code>in.reset()</code> method.
111 * @exception IOException
114 public void reset() throws IOException {
119 * Calls the <code>in.available()</code> method.
121 * @return The value returned from <code>in.available()</code>
123 * @exception IOException
126 public int available() throws IOException {
127 return in.available();
131 * Calls the <code>in.skip(long)</code> method
134 * The requested number of bytes to skip.
136 * @return The value returned from <code>in.skip(long)</code>
138 * @exception IOException
142 public long skip(long numBytes) throws IOException {
143 return in.skip(numBytes);
147 * Calls the <code>in.read()</code> method
149 * @return The value returned from <code>in.read()</code>
151 * @exception IOException
155 public int read() throws IOException {
160 * Calls the <code>read(byte[], int, int)</code> overloaded method. Note that
161 * this method does not redirect its call directly to a corresponding method
162 * in <code>in</code>. This allows subclasses to override only the three
163 * argument version of <code>read</code>.
166 * The buffer to read bytes into
168 * @return The value retured from <code>in.read(byte[], int, int)</code>
170 * @exception IOException
174 public int read(byte[] buf) throws IOException {
175 return read(buf, 0, buf.length);
179 * Calls the <code>in.read(byte[], int, int)</code> method.
182 * The buffer to read bytes into
184 * The index into the buffer to start storing bytes
186 * The maximum number of bytes to read.
188 * @return The value retured from <code>in.read(byte[], int, int)</code>
190 * @exception IOException
194 public int read(byte[] buf, int offset, int len) throws IOException {
195 return in.read(buf, offset, len);
199 * This method closes the input stream by closing the input stream that this
200 * object is filtering. Future attempts to access this stream may throw an
203 * @exception IOException
207 public void close() throws IOException {