--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/io/FilterInputStream.java Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,236 @@
+/*
+ * Copyright 1994-2006 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+package java.io;
+
+/**
+ * A <code>FilterInputStream</code> contains
+ * some other input stream, which it uses as
+ * its basic source of data, possibly transforming
+ * the data along the way or providing additional
+ * functionality. The class <code>FilterInputStream</code>
+ * itself simply overrides all methods of
+ * <code>InputStream</code> with versions that
+ * pass all requests to the contained input
+ * stream. Subclasses of <code>FilterInputStream</code>
+ * may further override some of these methods
+ * and may also provide additional methods
+ * and fields.
+ *
+ * @author Jonathan Payne
+ * @since JDK1.0
+ */
+public
+class FilterInputStream extends InputStream {
+ /**
+ * The input stream to be filtered.
+ */
+ protected volatile InputStream in;
+
+ /**
+ * Creates a <code>FilterInputStream</code>
+ * by assigning the argument <code>in</code>
+ * to the field <code>this.in</code> so as
+ * to remember it for later use.
+ *
+ * @param in the underlying input stream, or <code>null</code> if
+ * this instance is to be created without an underlying stream.
+ */
+ protected FilterInputStream(InputStream in) {
+ this.in = in;
+ }
+
+ /**
+ * Reads the next byte of data from this input stream. The value
+ * byte is returned as an <code>int</code> in the range
+ * <code>0</code> to <code>255</code>. If no byte is available
+ * because the end of the stream has been reached, the value
+ * <code>-1</code> is returned. This method blocks until input data
+ * is available, the end of the stream is detected, or an exception
+ * is thrown.
+ * <p>
+ * This method
+ * simply performs <code>in.read()</code> and returns the result.
+ *
+ * @return the next byte of data, or <code>-1</code> if the end of the
+ * stream is reached.
+ * @exception IOException if an I/O error occurs.
+ * @see java.io.FilterInputStream#in
+ */
+ public int read() throws IOException {
+ return in.read();
+ }
+
+ /**
+ * Reads up to <code>byte.length</code> bytes of data from this
+ * input stream into an array of bytes. This method blocks until some
+ * input is available.
+ * <p>
+ * This method simply performs the call
+ * <code>read(b, 0, b.length)</code> and returns
+ * the result. It is important that it does
+ * <i>not</i> do <code>in.read(b)</code> instead;
+ * certain subclasses of <code>FilterInputStream</code>
+ * depend on the implementation strategy actually
+ * used.
+ *
+ * @param b the buffer into which the data is read.
+ * @return the total number of bytes read into the buffer, or
+ * <code>-1</code> if there is no more data because the end of
+ * the stream has been reached.
+ * @exception IOException if an I/O error occurs.
+ * @see java.io.FilterInputStream#read(byte[], int, int)
+ */
+ public int read(byte b[]) throws IOException {
+ return read(b, 0, b.length);
+ }
+
+ /**
+ * Reads up to <code>len</code> bytes of data from this input stream
+ * into an array of bytes. If <code>len</code> is not zero, the method
+ * blocks until some input is available; otherwise, no
+ * bytes are read and <code>0</code> is returned.
+ * <p>
+ * This method simply performs <code>in.read(b, off, len)</code>
+ * and returns the result.
+ *
+ * @param b the buffer into which the data is read.
+ * @param off the start offset in the destination array <code>b</code>
+ * @param len the maximum number of bytes read.
+ * @return the total number of bytes read into the buffer, or
+ * <code>-1</code> if there is no more data because the end of
+ * the stream has been reached.
+ * @exception NullPointerException If <code>b</code> is <code>null</code>.
+ * @exception IndexOutOfBoundsException If <code>off</code> is negative,
+ * <code>len</code> is negative, or <code>len</code> is greater than
+ * <code>b.length - off</code>
+ * @exception IOException if an I/O error occurs.
+ * @see java.io.FilterInputStream#in
+ */
+ public int read(byte b[], int off, int len) throws IOException {
+ return in.read(b, off, len);
+ }
+
+ /**
+ * {@inheritDoc}
+ * <p>
+ * This method simply performs <code>in.skip(n)</code>.
+ */
+ public long skip(long n) throws IOException {
+ return in.skip(n);
+ }
+
+ /**
+ * Returns an estimate of the number of bytes that can be read (or
+ * skipped over) from this input stream without blocking by the next
+ * caller of a method for this input stream. The next caller might be
+ * the same thread or another thread. A single read or skip of this
+ * many bytes will not block, but may read or skip fewer bytes.
+ * <p>
+ * This method returns the result of {@link #in in}.available().
+ *
+ * @return an estimate of the number of bytes that can be read (or skipped
+ * over) from this input stream without blocking.
+ * @exception IOException if an I/O error occurs.
+ */
+ public int available() throws IOException {
+ return in.available();
+ }
+
+ /**
+ * Closes this input stream and releases any system resources
+ * associated with the stream.
+ * This
+ * method simply performs <code>in.close()</code>.
+ *
+ * @exception IOException if an I/O error occurs.
+ * @see java.io.FilterInputStream#in
+ */
+ public void close() throws IOException {
+ in.close();
+ }
+
+ /**
+ * Marks the current position in this input stream. A subsequent
+ * call to the <code>reset</code> method repositions this stream at
+ * the last marked position so that subsequent reads re-read the same bytes.
+ * <p>
+ * The <code>readlimit</code> argument tells this input stream to
+ * allow that many bytes to be read before the mark position gets
+ * invalidated.
+ * <p>
+ * This method simply performs <code>in.mark(readlimit)</code>.
+ *
+ * @param readlimit the maximum limit of bytes that can be read before
+ * the mark position becomes invalid.
+ * @see java.io.FilterInputStream#in
+ * @see java.io.FilterInputStream#reset()
+ */
+ public synchronized void mark(int readlimit) {
+ in.mark(readlimit);
+ }
+
+ /**
+ * Repositions this stream to the position at the time the
+ * <code>mark</code> method was last called on this input stream.
+ * <p>
+ * This method
+ * simply performs <code>in.reset()</code>.
+ * <p>
+ * Stream marks are intended to be used in
+ * situations where you need to read ahead a little to see what's in
+ * the stream. Often this is most easily done by invoking some
+ * general parser. If the stream is of the type handled by the
+ * parse, it just chugs along happily. If the stream is not of
+ * that type, the parser should toss an exception when it fails.
+ * If this happens within readlimit bytes, it allows the outer
+ * code to reset the stream and try another parser.
+ *
+ * @exception IOException if the stream has not been marked or if the
+ * mark has been invalidated.
+ * @see java.io.FilterInputStream#in
+ * @see java.io.FilterInputStream#mark(int)
+ */
+ public synchronized void reset() throws IOException {
+ in.reset();
+ }
+
+ /**
+ * Tests if this input stream supports the <code>mark</code>
+ * and <code>reset</code> methods.
+ * This method
+ * simply performs <code>in.markSupported()</code>.
+ *
+ * @return <code>true</code> if this stream type supports the
+ * <code>mark</code> and <code>reset</code> method;
+ * <code>false</code> otherwise.
+ * @see java.io.FilterInputStream#in
+ * @see java.io.InputStream#mark(int)
+ * @see java.io.InputStream#reset()
+ */
+ public boolean markSupported() {
+ return in.markSupported();
+ }
+}