1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/rt/emul/mini/src/main/java/java/io/FilterInputStream.java Tue Feb 26 16:54:16 2013 +0100
1.3 @@ -0,0 +1,245 @@
1.4 +/*
1.5 + * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation. Oracle designates this
1.11 + * particular file as subject to the "Classpath" exception as provided
1.12 + * by Oracle in the LICENSE file that accompanied this code.
1.13 + *
1.14 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.15 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.16 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.17 + * version 2 for more details (a copy is included in the LICENSE file that
1.18 + * accompanied this code).
1.19 + *
1.20 + * You should have received a copy of the GNU General Public License version
1.21 + * 2 along with this work; if not, write to the Free Software Foundation,
1.22 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.23 + *
1.24 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.25 + * or visit www.oracle.com if you need additional information or have any
1.26 + * questions.
1.27 + */
1.28 +
1.29 +package java.io;
1.30 +
1.31 +/**
1.32 + * A <code>FilterInputStream</code> contains
1.33 + * some other input stream, which it uses as
1.34 + * its basic source of data, possibly transforming
1.35 + * the data along the way or providing additional
1.36 + * functionality. The class <code>FilterInputStream</code>
1.37 + * itself simply overrides all methods of
1.38 + * <code>InputStream</code> with versions that
1.39 + * pass all requests to the contained input
1.40 + * stream. Subclasses of <code>FilterInputStream</code>
1.41 + * may further override some of these methods
1.42 + * and may also provide additional methods
1.43 + * and fields.
1.44 + *
1.45 + * @author Jonathan Payne
1.46 + * @since JDK1.0
1.47 + */
1.48 +public
1.49 +class FilterInputStream extends InputStream {
1.50 + /**
1.51 + * The input stream to be filtered.
1.52 + */
1.53 + protected volatile InputStream in;
1.54 +
1.55 + /**
1.56 + * Creates a <code>FilterInputStream</code>
1.57 + * by assigning the argument <code>in</code>
1.58 + * to the field <code>this.in</code> so as
1.59 + * to remember it for later use.
1.60 + *
1.61 + * @param in the underlying input stream, or <code>null</code> if
1.62 + * this instance is to be created without an underlying stream.
1.63 + */
1.64 + protected FilterInputStream(InputStream in) {
1.65 + this.in = in;
1.66 + }
1.67 +
1.68 + /**
1.69 + * Reads the next byte of data from this input stream. The value
1.70 + * byte is returned as an <code>int</code> in the range
1.71 + * <code>0</code> to <code>255</code>. If no byte is available
1.72 + * because the end of the stream has been reached, the value
1.73 + * <code>-1</code> is returned. This method blocks until input data
1.74 + * is available, the end of the stream is detected, or an exception
1.75 + * is thrown.
1.76 + * <p>
1.77 + * This method
1.78 + * simply performs <code>in.read()</code> and returns the result.
1.79 + *
1.80 + * @return the next byte of data, or <code>-1</code> if the end of the
1.81 + * stream is reached.
1.82 + * @exception IOException if an I/O error occurs.
1.83 + * @see java.io.FilterInputStream#in
1.84 + */
1.85 + public int read() throws IOException {
1.86 + return in.read();
1.87 + }
1.88 +
1.89 + /**
1.90 + * Reads up to <code>byte.length</code> bytes of data from this
1.91 + * input stream into an array of bytes. This method blocks until some
1.92 + * input is available.
1.93 + * <p>
1.94 + * This method simply performs the call
1.95 + * <code>read(b, 0, b.length)</code> and returns
1.96 + * the result. It is important that it does
1.97 + * <i>not</i> do <code>in.read(b)</code> instead;
1.98 + * certain subclasses of <code>FilterInputStream</code>
1.99 + * depend on the implementation strategy actually
1.100 + * used.
1.101 + *
1.102 + * @param b the buffer into which the data is read.
1.103 + * @return the total number of bytes read into the buffer, or
1.104 + * <code>-1</code> if there is no more data because the end of
1.105 + * the stream has been reached.
1.106 + * @exception IOException if an I/O error occurs.
1.107 + * @see java.io.FilterInputStream#read(byte[], int, int)
1.108 + */
1.109 + public int read(byte b[]) throws IOException {
1.110 + return read(b, 0, b.length);
1.111 + }
1.112 +
1.113 + /**
1.114 + * Reads up to <code>len</code> bytes of data from this input stream
1.115 + * into an array of bytes. If <code>len</code> is not zero, the method
1.116 + * blocks until some input is available; otherwise, no
1.117 + * bytes are read and <code>0</code> is returned.
1.118 + * <p>
1.119 + * This method simply performs <code>in.read(b, off, len)</code>
1.120 + * and returns the result.
1.121 + *
1.122 + * @param b the buffer into which the data is read.
1.123 + * @param off the start offset in the destination array <code>b</code>
1.124 + * @param len the maximum number of bytes read.
1.125 + * @return the total number of bytes read into the buffer, or
1.126 + * <code>-1</code> if there is no more data because the end of
1.127 + * the stream has been reached.
1.128 + * @exception NullPointerException If <code>b</code> is <code>null</code>.
1.129 + * @exception IndexOutOfBoundsException If <code>off</code> is negative,
1.130 + * <code>len</code> is negative, or <code>len</code> is greater than
1.131 + * <code>b.length - off</code>
1.132 + * @exception IOException if an I/O error occurs.
1.133 + * @see java.io.FilterInputStream#in
1.134 + */
1.135 + public int read(byte b[], int off, int len) throws IOException {
1.136 + return in.read(b, off, len);
1.137 + }
1.138 +
1.139 + /**
1.140 + * Skips over and discards <code>n</code> bytes of data from the
1.141 + * input stream. The <code>skip</code> method may, for a variety of
1.142 + * reasons, end up skipping over some smaller number of bytes,
1.143 + * possibly <code>0</code>. The actual number of bytes skipped is
1.144 + * returned.
1.145 + * <p>
1.146 + * This method simply performs <code>in.skip(n)</code>.
1.147 + *
1.148 + * @param n the number of bytes to be skipped.
1.149 + * @return the actual number of bytes skipped.
1.150 + * @exception IOException if the stream does not support seek,
1.151 + * or if some other I/O error occurs.
1.152 + */
1.153 + public long skip(long n) throws IOException {
1.154 + return in.skip(n);
1.155 + }
1.156 +
1.157 + /**
1.158 + * Returns an estimate of the number of bytes that can be read (or
1.159 + * skipped over) from this input stream without blocking by the next
1.160 + * caller of a method for this input stream. The next caller might be
1.161 + * the same thread or another thread. A single read or skip of this
1.162 + * many bytes will not block, but may read or skip fewer bytes.
1.163 + * <p>
1.164 + * This method returns the result of {@link #in in}.available().
1.165 + *
1.166 + * @return an estimate of the number of bytes that can be read (or skipped
1.167 + * over) from this input stream without blocking.
1.168 + * @exception IOException if an I/O error occurs.
1.169 + */
1.170 + public int available() throws IOException {
1.171 + return in.available();
1.172 + }
1.173 +
1.174 + /**
1.175 + * Closes this input stream and releases any system resources
1.176 + * associated with the stream.
1.177 + * This
1.178 + * method simply performs <code>in.close()</code>.
1.179 + *
1.180 + * @exception IOException if an I/O error occurs.
1.181 + * @see java.io.FilterInputStream#in
1.182 + */
1.183 + public void close() throws IOException {
1.184 + in.close();
1.185 + }
1.186 +
1.187 + /**
1.188 + * Marks the current position in this input stream. A subsequent
1.189 + * call to the <code>reset</code> method repositions this stream at
1.190 + * the last marked position so that subsequent reads re-read the same bytes.
1.191 + * <p>
1.192 + * The <code>readlimit</code> argument tells this input stream to
1.193 + * allow that many bytes to be read before the mark position gets
1.194 + * invalidated.
1.195 + * <p>
1.196 + * This method simply performs <code>in.mark(readlimit)</code>.
1.197 + *
1.198 + * @param readlimit the maximum limit of bytes that can be read before
1.199 + * the mark position becomes invalid.
1.200 + * @see java.io.FilterInputStream#in
1.201 + * @see java.io.FilterInputStream#reset()
1.202 + */
1.203 + public synchronized void mark(int readlimit) {
1.204 + in.mark(readlimit);
1.205 + }
1.206 +
1.207 + /**
1.208 + * Repositions this stream to the position at the time the
1.209 + * <code>mark</code> method was last called on this input stream.
1.210 + * <p>
1.211 + * This method
1.212 + * simply performs <code>in.reset()</code>.
1.213 + * <p>
1.214 + * Stream marks are intended to be used in
1.215 + * situations where you need to read ahead a little to see what's in
1.216 + * the stream. Often this is most easily done by invoking some
1.217 + * general parser. If the stream is of the type handled by the
1.218 + * parse, it just chugs along happily. If the stream is not of
1.219 + * that type, the parser should toss an exception when it fails.
1.220 + * If this happens within readlimit bytes, it allows the outer
1.221 + * code to reset the stream and try another parser.
1.222 + *
1.223 + * @exception IOException if the stream has not been marked or if the
1.224 + * mark has been invalidated.
1.225 + * @see java.io.FilterInputStream#in
1.226 + * @see java.io.FilterInputStream#mark(int)
1.227 + */
1.228 + public synchronized void reset() throws IOException {
1.229 + in.reset();
1.230 + }
1.231 +
1.232 + /**
1.233 + * Tests if this input stream supports the <code>mark</code>
1.234 + * and <code>reset</code> methods.
1.235 + * This method
1.236 + * simply performs <code>in.markSupported()</code>.
1.237 + *
1.238 + * @return <code>true</code> if this stream type supports the
1.239 + * <code>mark</code> and <code>reset</code> method;
1.240 + * <code>false</code> otherwise.
1.241 + * @see java.io.FilterInputStream#in
1.242 + * @see java.io.InputStream#mark(int)
1.243 + * @see java.io.InputStream#reset()
1.244 + */
1.245 + public boolean markSupported() {
1.246 + return in.markSupported();
1.247 + }
1.248 +}