connectionbuffer.java

Java Communicating Agents是一个用于开发网络反应式信息agent的框架

/*
 * $Source: /home/data/cvsroot/src/jacomma/platform/engine/ConnectionBuffer.java,v $
 * $Revision: 1.7 $
 * $Date: 2000/10/28 20:09:08 $
 *
 * This file is part of the jacomma framework
 * Copyright (c) 2000 	Dimitrios Vyzovitis
 *			mailto:[e-mail]
 *			
 *
 *			
 *			
 *			
 *
 *	This library is free software; you can redistribute it and/or modify
 *	it under the terms of the GNU Library General Public License as published by
 *	the Free Software Foundation; either version 2 of the License, or
 *	(at your option) any later version.
 *
 *	This library 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 Library General Public License for more details.
 *
 *	You should have received a copy of the GNU Library General Public License
 *	along with this library; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, 
 *	Boston, MA  02111-1307  USA
 */

package jacomma.platform.engine;

import jacomma.icm.type.Message;

import jacomma.icm.io.Connection;


/**
 * TBA
 **/
class ConnectionBuffer implements MessageBuffer, Runnable {
	
	Connection conn_;
	MessageBuffer buf_;
	
	Thread thread_;
	boolean active_;

	ConnectionBuffer( Connection conn, MessageBuffer buf ) {
		conn_ = conn;
		buf_ = buf;
	}
	
	synchronized Thread startReader( ThreadGroup tg ) {
		if ( !active_ ) {
			active_ = true;
			(thread_ = new Thread( tg, this, toString() + " - Reader Thread" )).start();
			return thread_;
		} else
			return null;
	}
	
	synchronized void stopReader() {
		if ( active_ ) {
			active_ = false;
			thread_.interrupt();
		}
	}
	
	synchronized boolean isActive() { 
		return active_ && !thread_.isInterrupted(); 
	}

	public void put( Message msg ) throws java.io.IOException {
		conn_.writeObject( msg );
	}
	
	public void run() {
		while( isActive() ) try {
			buf_.put( (Message)conn_.readObject() );
			// Attempt to fix the 100% CPU utilization behavior incurred by LinuxThreads
			Thread.currentThread().yield();
		} catch ( Exception exc ) {
			// we don't know how to handle any exception
			// The ThreadGroup can let the Reader run if it is a non-critical
			// situation or interrupt the thread to force us exit the loop
			thread_.getThreadGroup().uncaughtException( thread_, exc );
		}
		
	}
	
	
}