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//******************************************************************************
//
// File: LoopbackChannel.java
// Package: edu.rit.mp
// Unit: Class edu.rit.mp.LoopbackChannel
//
// This Java source file is copyright (C) 2008 by Alan Kaminsky. All rights
// reserved. For further information, contact the author, Alan Kaminsky, at
// ark@cs.rit.edu.
//
// This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
// software; you can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// PJ 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 for more details.
//
// Linking this library statically or dynamically with other modules is making a
// combined work based on this library. Thus, the terms and conditions of the
// GNU General Public License cover the whole combination.
//
// As a special exception, the copyright holders of this library give you
// permission to link this library with independent modules to produce an
// executable, regardless of the license terms of these independent modules, and
// to copy and distribute the resulting executable under terms of your choice,
// provided that you also meet, for each linked independent module, the terms
// and conditions of the license of that module. An independent module is a
// module which is not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the library, but
// you are not obligated to do so. If you do not wish to do so, delete this
// exception statement from your version.
//
// A copy of the GNU General Public License is provided in the file gpl.txt. You
// may also obtain a copy of the GNU General Public License on the World Wide
// Web at http://www.gnu.org/licenses/gpl.html.
//
//******************************************************************************
package edu.rit.mp;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.InetSocketAddress;
/**
* Class LoopbackChannel provides a channel for sending and receiving messages
* within the same process in the Message Protocol (MP).
*
* @author Alan Kaminsky
* @version 13-May-2008
*/
class LoopbackChannel
extends Channel
{
// Hidden constructors.
/**
* Construct a new loopback channel.
*
* @param theChannelGroup Enclosing channel group.
*/
LoopbackChannel
(ChannelGroup theChannelGroup)
{
super (theChannelGroup);
}
// Exported operations.
/**
* Obtain the channel group ID of this channel's near end channel group.
*
* @return Near end channel group ID.
*/
public int nearEndChannelGroupId()
{
return myChannelGroup.myChannelGroupId;
}
/**
* Obtain the channel group ID of this channel's far end channel group.
*
* @return Far end channel group ID.
*/
public int farEndChannelGroupId()
{
return myChannelGroup.myChannelGroupId;
}
/**
* Obtain this channel's near end address. This is the host and port of the
* near end of this channel's connection.
*
* @return Near end address.
*/
public InetSocketAddress nearEndAddress()
{
return new InetSocketAddress (0);
}
/**
* Obtain this channel's far end address. This is the host and port of the
* far end of this channel's connection.
*
* @return Far end address.
*/
public InetSocketAddress farEndAddress()
{
return new InetSocketAddress (0);
}
// Hidden operations.
/**
* Send a message via this channel. The I/O request object must be newly
* constructed with the message tag and source buffer fields filled in. This
* method is allowed to return immediately and let the message be sent in a
* separate thread. The calling thread should use the I/O request object to
* wait for the message send to complete.
*
* @param theIORequest I/O request object.
*
* @exception IOException
* Thrown if an I/O error occurred.
*/
void send
(IORequest theIORequest)
throws IOException
{
synchronized (this)
{
// Check whether channel is closed.
if (myWriteState == WRITE_CLOSED)
{
throw new IOException
("edu.rit.mp.LoopbackChannel: Channel closed");
}
}
// Wait until there is a matching receive request.
IORequest recvRequest;
try
{
recvRequest = myIORequestList.waitForMatch (theIORequest);
}
catch (InterruptedException exc)
{
IOException exc2 =
new InterruptedIOException
("edu.rit.mp.LoopbackChannel: Send interrupted");
exc2.initCause (exc);
throw exc2;
}
// Copy source buffer to destination buffer.
recvRequest.myBuf.copy (theIORequest.myBuf);
// Set up status object.
recvRequest.myStatus =
new Status
(this,
theIORequest.myTagLb,
theIORequest.myBuf.myLength);
// Report success.
theIORequest.reportSuccess();
recvRequest.reportSuccess();
}
}
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