1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/emul/compact/src/main/java/java/io/Reader.java Wed Jan 23 22:32:27 2013 +0100
1.3 @@ -0,0 +1,262 @@
1.4 +/*
1.5 + * Copyright (c) 1996, 2006, 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 +/**
1.33 + * Abstract class for reading character streams. The only methods that a
1.34 + * subclass must implement are read(char[], int, int) and close(). Most
1.35 + * subclasses, however, will override some of the methods defined here in order
1.36 + * to provide higher efficiency, additional functionality, or both.
1.37 + *
1.38 + *
1.39 + * @see BufferedReader
1.40 + * @see LineNumberReader
1.41 + * @see CharArrayReader
1.42 + * @see InputStreamReader
1.43 + * @see FileReader
1.44 + * @see FilterReader
1.45 + * @see PushbackReader
1.46 + * @see PipedReader
1.47 + * @see StringReader
1.48 + * @see Writer
1.49 + *
1.50 + * @author Mark Reinhold
1.51 + * @since JDK1.1
1.52 + */
1.53 +
1.54 +public abstract class Reader implements Readable, Closeable {
1.55 +
1.56 + /**
1.57 + * The object used to synchronize operations on this stream. For
1.58 + * efficiency, a character-stream object may use an object other than
1.59 + * itself to protect critical sections. A subclass should therefore use
1.60 + * the object in this field rather than <tt>this</tt> or a synchronized
1.61 + * method.
1.62 + */
1.63 + protected Object lock;
1.64 +
1.65 + /**
1.66 + * Creates a new character-stream reader whose critical sections will
1.67 + * synchronize on the reader itself.
1.68 + */
1.69 + protected Reader() {
1.70 + this.lock = this;
1.71 + }
1.72 +
1.73 + /**
1.74 + * Creates a new character-stream reader whose critical sections will
1.75 + * synchronize on the given object.
1.76 + *
1.77 + * @param lock The Object to synchronize on.
1.78 + */
1.79 + protected Reader(Object lock) {
1.80 + if (lock == null) {
1.81 + throw new NullPointerException();
1.82 + }
1.83 + this.lock = lock;
1.84 + }
1.85 +
1.86 + /**
1.87 + * Attempts to read characters into the specified character buffer.
1.88 + * The buffer is used as a repository of characters as-is: the only
1.89 + * changes made are the results of a put operation. No flipping or
1.90 + * rewinding of the buffer is performed.
1.91 + *
1.92 + * @param target the buffer to read characters into
1.93 + * @return The number of characters added to the buffer, or
1.94 + * -1 if this source of characters is at its end
1.95 + * @throws IOException if an I/O error occurs
1.96 + * @throws NullPointerException if target is null
1.97 + * @throws ReadOnlyBufferException if target is a read only buffer
1.98 + * @since 1.5
1.99 + */
1.100 + public int read(java.nio.CharBuffer target) throws IOException {
1.101 + int len = target.remaining();
1.102 + char[] cbuf = new char[len];
1.103 + int n = read(cbuf, 0, len);
1.104 + if (n > 0)
1.105 + target.put(cbuf, 0, n);
1.106 + return n;
1.107 + }
1.108 +
1.109 + /**
1.110 + * Reads a single character. This method will block until a character is
1.111 + * available, an I/O error occurs, or the end of the stream is reached.
1.112 + *
1.113 + * <p> Subclasses that intend to support efficient single-character input
1.114 + * should override this method.
1.115 + *
1.116 + * @return The character read, as an integer in the range 0 to 65535
1.117 + * (<tt>0x00-0xffff</tt>), or -1 if the end of the stream has
1.118 + * been reached
1.119 + *
1.120 + * @exception IOException If an I/O error occurs
1.121 + */
1.122 + public int read() throws IOException {
1.123 + char cb[] = new char[1];
1.124 + if (read(cb, 0, 1) == -1)
1.125 + return -1;
1.126 + else
1.127 + return cb[0];
1.128 + }
1.129 +
1.130 + /**
1.131 + * Reads characters into an array. This method will block until some input
1.132 + * is available, an I/O error occurs, or the end of the stream is reached.
1.133 + *
1.134 + * @param cbuf Destination buffer
1.135 + *
1.136 + * @return The number of characters read, or -1
1.137 + * if the end of the stream
1.138 + * has been reached
1.139 + *
1.140 + * @exception IOException If an I/O error occurs
1.141 + */
1.142 + public int read(char cbuf[]) throws IOException {
1.143 + return read(cbuf, 0, cbuf.length);
1.144 + }
1.145 +
1.146 + /**
1.147 + * Reads characters into a portion of an array. This method will block
1.148 + * until some input is available, an I/O error occurs, or the end of the
1.149 + * stream is reached.
1.150 + *
1.151 + * @param cbuf Destination buffer
1.152 + * @param off Offset at which to start storing characters
1.153 + * @param len Maximum number of characters to read
1.154 + *
1.155 + * @return The number of characters read, or -1 if the end of the
1.156 + * stream has been reached
1.157 + *
1.158 + * @exception IOException If an I/O error occurs
1.159 + */
1.160 + abstract public int read(char cbuf[], int off, int len) throws IOException;
1.161 +
1.162 + /** Maximum skip-buffer size */
1.163 + private static final int maxSkipBufferSize = 8192;
1.164 +
1.165 + /** Skip buffer, null until allocated */
1.166 + private char skipBuffer[] = null;
1.167 +
1.168 + /**
1.169 + * Skips characters. This method will block until some characters are
1.170 + * available, an I/O error occurs, or the end of the stream is reached.
1.171 + *
1.172 + * @param n The number of characters to skip
1.173 + *
1.174 + * @return The number of characters actually skipped
1.175 + *
1.176 + * @exception IllegalArgumentException If <code>n</code> is negative.
1.177 + * @exception IOException If an I/O error occurs
1.178 + */
1.179 + public long skip(long n) throws IOException {
1.180 + if (n < 0L)
1.181 + throw new IllegalArgumentException("skip value is negative");
1.182 + int nn = (int) Math.min(n, maxSkipBufferSize);
1.183 + synchronized (lock) {
1.184 + if ((skipBuffer == null) || (skipBuffer.length < nn))
1.185 + skipBuffer = new char[nn];
1.186 + long r = n;
1.187 + while (r > 0) {
1.188 + int nc = read(skipBuffer, 0, (int)Math.min(r, nn));
1.189 + if (nc == -1)
1.190 + break;
1.191 + r -= nc;
1.192 + }
1.193 + return n - r;
1.194 + }
1.195 + }
1.196 +
1.197 + /**
1.198 + * Tells whether this stream is ready to be read.
1.199 + *
1.200 + * @return True if the next read() is guaranteed not to block for input,
1.201 + * false otherwise. Note that returning false does not guarantee that the
1.202 + * next read will block.
1.203 + *
1.204 + * @exception IOException If an I/O error occurs
1.205 + */
1.206 + public boolean ready() throws IOException {
1.207 + return false;
1.208 + }
1.209 +
1.210 + /**
1.211 + * Tells whether this stream supports the mark() operation. The default
1.212 + * implementation always returns false. Subclasses should override this
1.213 + * method.
1.214 + *
1.215 + * @return true if and only if this stream supports the mark operation.
1.216 + */
1.217 + public boolean markSupported() {
1.218 + return false;
1.219 + }
1.220 +
1.221 + /**
1.222 + * Marks the present position in the stream. Subsequent calls to reset()
1.223 + * will attempt to reposition the stream to this point. Not all
1.224 + * character-input streams support the mark() operation.
1.225 + *
1.226 + * @param readAheadLimit Limit on the number of characters that may be
1.227 + * read while still preserving the mark. After
1.228 + * reading this many characters, attempting to
1.229 + * reset the stream may fail.
1.230 + *
1.231 + * @exception IOException If the stream does not support mark(),
1.232 + * or if some other I/O error occurs
1.233 + */
1.234 + public void mark(int readAheadLimit) throws IOException {
1.235 + throw new IOException("mark() not supported");
1.236 + }
1.237 +
1.238 + /**
1.239 + * Resets the stream. If the stream has been marked, then attempt to
1.240 + * reposition it at the mark. If the stream has not been marked, then
1.241 + * attempt to reset it in some way appropriate to the particular stream,
1.242 + * for example by repositioning it to its starting point. Not all
1.243 + * character-input streams support the reset() operation, and some support
1.244 + * reset() without supporting mark().
1.245 + *
1.246 + * @exception IOException If the stream has not been marked,
1.247 + * or if the mark has been invalidated,
1.248 + * or if the stream does not support reset(),
1.249 + * or if some other I/O error occurs
1.250 + */
1.251 + public void reset() throws IOException {
1.252 + throw new IOException("reset() not supported");
1.253 + }
1.254 +
1.255 + /**
1.256 + * Closes the stream and releases any system resources associated with
1.257 + * it. Once the stream has been closed, further read(), ready(),
1.258 + * mark(), reset(), or skip() invocations will throw an IOException.
1.259 + * Closing a previously closed stream has no effect.
1.260 + *
1.261 + * @exception IOException If an I/O error occurs
1.262 + */
1.263 + abstract public void close() throws IOException;
1.264 +
1.265 +}