/*
* Copyright (c) 2001-2007 Sun Microsystems, Inc. All rights reserved.
*
* The Sun Project JXTA(TM) Software License
*
* 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 Sun Microsystems, Inc. for JXTA(TM) technology."
* 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.
*
* JXTA is a registered trademark of Sun Microsystems, Inc. in the United
* States and other countries.
*
* Please see the license information page at :
* <http://www.jxta.org/project/www/license.html> for instructions on use of
* the license in source files.
*
* ====================================================================
*
* 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.
*/
package net.jxta.test.util;
import java.io.ByteArrayInputStream;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
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/>
* <p/>Debugging toString.
*/
@Override
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 satisfaction.
*
* @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) {
;
}
}
@Override
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();
}
@Override
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.
@Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
@Override
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;
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;
}
}
}