/* * Copyright (c) 2001 Sun Microsystems, Inc.  All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in *    the documentation and/or other materials provided with the *    distribution. * * 3. The end-user documentation included with the redistribution, *    if any, must include the following acknowledgment: *       "This product includes software developed by the *       Sun Microsystems, Inc. for Project JXTA." *    Alternately, this acknowledgment may appear in the software itself, *    if and wherever such third-party acknowledgments normally appear. * * 4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA" must *    not be used to endorse or promote products derived from this *    software without prior written permission. For written *    permission, please contact Project JXTA at http://www.jxta.org. * * 5. Products derived from this software may not be called "JXTA", *    nor may "JXTA" appear in their name, without prior written *    permission of Sun. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED.  IN NO EVENT SHALL SUN MICROSYSTEMS OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of Project JXTA.  For more * information on Project JXTA, please see * <http://www.jxta.org/>. * * This license is based on the BSD license adopted by the Apache Foundation. * * $Id: WatchedInputStream.java,v 1.6 2004/05/30 12:27:40 jice Exp $ */package net.jxta.util;import java.io.*;import java.util.Collection;public class WatchedInputStream extends FilterInputStream    implements WatchedStream {    static final int DEFAULT_CHUNK_SIZE = 4096;    Collection watchList = null;    volatile boolean stalled = false;    volatile boolean idle = true;    boolean closed = false;    final int chunkSize;    InputStream in = null;    public WatchedInputStream(InputStream in, int chunkSize) {        super(in);        this.in = in;        this.chunkSize = chunkSize;    }    public WatchedInputStream(InputStream in) {        this(in, DEFAULT_CHUNK_SIZE);    }    /**     * {@inheritDoc}     *     *  <p/>Debugging toString.     **/    public String toString() {        if( null == in ) {            return "closed/" + super.toString();        } else {            if( in instanceof ByteArrayInputStream ) {                // ByteArrayInputStream.toString() prints the entire stream!                 return in.getClass().getName() + "@" + System.identityHashCode(in)  + "/" + super.toString();            } else {                return in.toString() + "/" + super.toString();            }        }    }        /**     * Sets the watcher list onto which this stream must register     * when it is not idle (so that it can be watched).     * This implementation may or may not remain registered while idle.     * This may affect performance but not functionality.     * It is assumed that that list is monitored by a watcher task that     * invokes the watch method as often as needed to monitor progress     * to its satifaction.     *     * @param watchList The watchList to register with. Must be a     * Synchronized Collection.     */    public synchronized void setWatchList(Collection watchList) {        if (this.watchList != null) {            this.watchList.remove(this);        }        this.watchList = watchList;        watchList.add(this);    }		    // This routine may be invoked as often as progress needs to be asserted.    // After at most two watch cycles stalling is detected.    public void watch() {        if (idle) return;        if (! stalled) {            stalled = true; // challenge a write method to clear that flag.            return;        }        // It's stalled. The last time around it was not idle, so we set the        // stalled flag. Now, it is still not idle and the flag is still there.        // break the stream.        try {            close();        } catch (IOException ioe) { ; }    }    public void close() throws IOException {        idle = true;        synchronized(this) {            if (watchList != null) {                watchList.remove(this);                watchList = null;            }            // Avoid calling close redundantly; some OSes seem to have            // deadlock capabilities when doing that.                        if (closed) return;            closed = true;        }        super.close();    }    public int read() throws IOException {        stalled = false;        idle = false;        try {            return in.read();        } finally {            idle = true;        }    }    // We overload it; not trusting that the base classes method does    // call read(byte[], int, int) in the future.    public int read(byte[] b) throws IOException {        return read(b, 0, b.length);    }    public int read(byte[] b, int off, int len) throws IOException {        // Apply the standard checks here; we will call in.read repeatedly        // which means that errors could be discovered too late per read's        // contract.        if (   (off < 0) || (len < 0) || ((off + len) > b.length)            || ((off + len) < 0)) {	    throw new IndexOutOfBoundsException();	}        stalled = false;        idle = false;        int left = len;        try {            int i = 0;            while (left > chunkSize) {                i = in.read(b, off, chunkSize);                stalled = false;                if (i <= 0) {                    if (left == len) return i;                    return len - left;                }                off += i;                left -= i;                // Must check available only after firt read.                // first read must wait for at least one byte.                if (in.available() == 0) {                    return len - left;                }            }            // Read the left over now. If this is not the first read,            // available has been checked in the loop above.            i = in.read(b, off, left);            if (i <= 0) {                if (left == len) return i;                return len - left;            }            return len - left + i;        } finally {            idle = true;        }    }}