/*
* 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.impl.endpoint;
import net.jxta.endpoint.EndpointAddress;
import net.jxta.endpoint.EndpointService;
import net.jxta.endpoint.Message;
import net.jxta.impl.peergroup.GenericPeerGroup;
import net.jxta.logging.Logging;
import net.jxta.peergroup.PeerGroup;
import java.io.IOException;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* This class implements local delivery of messages (for example when the
* InputPipe and the OutputPipe are located on the same peer)
* <p/>
* The reason this class is useful is that it may not always be possible to
* connect to oneself without actually through the relay. i.e. A peer with outgoing
* only http transport, can not possibly connect to self through the transport.
* <p/>
* Since transports cannot be relied on to perform a loopback, some layer
* above has to figure out that a message is looping back.
* Since peerid loopback does not explicitly request to go through a real
* transport, and since peerid addressing is the job of the router, it is
* the router that performs loopback.
* <p/>
* The router could probably perform the loopback by delivering the message
* to its own input queue, that would take a special transport instead of a
* special messenger, which is the same kind of deal but would imply some
* incoming message processing by the router for every message. In
* contrast, the loopback messenger is setup once and the router will never
* sees the messages. That's a good optimization.
* <p/>
* Alternatively, the endpoint service itself could figure out the
* loopback, but since the API wants to give a messenger to the requestor
* rather than just sending a message, the endpoint would have to setup a
* loopback messenger anyway. So it is pretty much the same.
*/
public class LoopbackMessenger extends BlockingMessenger {
/**
* Logger
*/
private final static transient Logger LOG = Logger.getLogger(LoopbackMessenger.class.getName());
/**
* The peergroup we are working for, ie. that we will loop back to.
*/
private final PeerGroup group;
/**
* The endpoint we are working for, ie. that we will loop back to.
*/
private final EndpointService endpoint;
/**
* The source address of messages sent on this messenger.
*/
private final EndpointAddress srcAddress;
/**
* The location destination of this messenger.
*/
private final EndpointAddress logicalDestination;
/**
* Used to ensure that only a single message is demuxed at a time.
*/
private final Lock orderingLock = new ReentrantLock(true);
/**
* Create a new loopback messenger.
*
* @param group The group context.
* @param ep where messages go
* @param src who messages should be addressed from
* @param dest who messages should be addressed to
* @param logicalDest The logical destination address.
*/
public LoopbackMessenger(PeerGroup group, EndpointService ep, EndpointAddress src, EndpointAddress dest, EndpointAddress logicalDest) {
super(group.getPeerGroupID(), dest, false);
this.group = group;
endpoint = ep;
srcAddress = src;
logicalDestination = logicalDest;
}
/**
* {@inheritDoc}
*/
@Override
public EndpointAddress getLogicalDestinationImpl() {
return logicalDestination;
}
/**
* {@inheritDoc}
*/
@Override
public long getMTU() {
return Long.MAX_VALUE;
}
/**
* {@inheritDoc}
*/
@Override
public boolean isIdleImpl() {
return false;
}
/**
* {@inheritDoc}
*/
@Override
public void closeImpl() {}
/**
* {@inheritDoc}
*/
@Override
public void sendMessageBImpl(final Message message, final String service, final String serviceParam) throws IOException {
if (isClosed()) {
IOException failure = new IOException("Messenger was closed, it cannot be used to send messages.");
if (Logging.SHOW_WARNING && LOG.isLoggable(Level.WARNING)) {
LOG.log(Level.WARNING, failure.getMessage(), failure);
}
throw failure;
}
orderingLock.lock();
try {
// Process the message with the appropriate src and dest address
((GenericPeerGroup)group).getExecutor().execute( new Runnable() {
public void run() {
try {
endpoint.processIncomingMessage(message, srcAddress, getDestAddressToUse(service, serviceParam));
} catch(Throwable uncaught) {
if (Logging.SHOW_WARNING && LOG.isLoggable(Level.WARNING)) {
LOG.log(Level.WARNING, "Uncaught Throwable in Loopback Messenger ", uncaught);
}
}
}
});
} finally {
orderingLock.unlock();
}
}
}