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/*******************************************************************************
* Copyright (c) 2010 protos software gmbh (http://www.protos.de).
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* CONTRIBUTORS:
* Thomas Schuetz and Henrik Rentz-Reichert (initial contribution)
*
*******************************************************************************/
package org.eclipse.etrice.runtime.java.messaging;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
/**
* The MessageService is the backbone of the asynchronous communication inside a SubSystem
* It usually contains a thread a message queue and a dispatcher
*
* @author Thomas Schuetz (initial contribution)
* @author Henrik Rentz-Reichert (extending RTObject, implementing Runnable)
*
*/
public class MessageService extends AbstractMessageService {
private boolean running = false;
private Thread thread;
private int priority;
private long lastMessageTimestamp;
private int pollingInterval = -1;
private ScheduledExecutorService pollingScheduler = null;
public MessageService(IRTObject parent, ExecMode mode, int node, int thread, String name) {
this(parent, mode, 0, node, thread, name, Thread.NORM_PRIORITY);
}
public MessageService(IRTObject parent, ExecMode mode, int nsec, int node, int thread, String name) {
this(parent, mode, nsec, node, thread, name, Thread.NORM_PRIORITY);
}
public MessageService(IRTObject parent, ExecMode mode, int nsec, int node, int thread, String name, int priority) {
super(parent, "MessageService_"+name, node, thread);
// Java thread priority is limited to 1-10 and cannot be changed
// thus priorities from physical mapping are not generated
// priority = Thread.NORM_PRIORITY generated fixed
this.priority = priority;
assert priority >= Thread.MIN_PRIORITY : ("priority smaller than Thread.MIN_PRIORITY (" + "Thread.MIN_PRIORITY" + ")");
assert priority <= Thread.MAX_PRIORITY : ("priority bigger than Thread.MAX_PRIORITY (" + "Thread.MAX_PRIORITY" + ")");
if(mode == ExecMode.MIXED || mode == ExecMode.POLLED){
pollingInterval = nsec;
pollingScheduler = Executors.newScheduledThreadPool(1, new PollingThreadFactory());
assert pollingInterval > 0 : ("polling interval is 0 or negative");
}
}
public void run() {
running = true;
if(pollingScheduler != null)
pollingScheduler.scheduleAtFixedRate(new PollingTask(), pollingInterval, pollingInterval, TimeUnit.NANOSECONDS);
while (running) {
Message msg = null;
// get next Message from Queue
synchronized(this) {
msg = getMessageQueue().pop();
}
if (msg == null) {
// no message in queue -> wait until Thread is notified
try {
synchronized(this) {
if (!running)
return;
wait();
}
}
catch (InterruptedException e) {
}
}
else {
// process message
lastMessageTimestamp = System.currentTimeMillis();
getMessageDispatcher().receive(msg);
}
}
}
/* (non-Javadoc)
* @see org.eclipse.etrice.runtime.java.messaging.AbstractMessageService#receive(org.eclipse.etrice.runtime.java.messaging.Message)
*/
@Override
public synchronized void receive(Message msg) {
super.receive(msg);
// wake up thread to process message
notifyAll();
}
/* (non-Javadoc)
* @see org.eclipse.etrice.runtime.java.messaging.AbstractMessageService#getFreeAddress()
*/
@Override
public synchronized Address getFreeAddress() {
return super.getFreeAddress();
}
/* (non-Javadoc)
* @see org.eclipse.etrice.runtime.java.messaging.AbstractMessageService#addMessageReceiver(org.eclipse.etrice.runtime.java.messaging.IMessageReceiver)
*/
@Override
public synchronized void addMessageReceiver(IMessageReceiver receiver) {
super.addMessageReceiver(receiver);
}
/* (non-Javadoc)
* @see org.eclipse.etrice.runtime.java.messaging.AbstractMessageService#removeMessageReceiver(org.eclipse.etrice.runtime.java.messaging.IMessageReceiver)
*/
@Override
public synchronized void removeMessageReceiver(IMessageReceiver receiver) {
super.removeMessageReceiver(receiver);
}
@Override
public synchronized void addPollingMessageReceiver(IMessageReceiver receiver) {
super.addPollingMessageReceiver(receiver);
}
@Override
public synchronized void removePollingMessageReceiver(IMessageReceiver receiver) {
super.removePollingMessageReceiver(receiver);
}
/* (non-Javadoc)
* @see org.eclipse.etrice.runtime.java.messaging.AbstractMessageService#freeAddress(org.eclipse.etrice.runtime.java.messaging.Address)
*/
@Override
public synchronized void freeAddress(Address addr) {
super.freeAddress(addr);
}
public synchronized void terminate() {
if (running) {
running = false;
notifyAll();
}
if(pollingScheduler != null)
pollingScheduler.shutdown();
}
/* (non-Javadoc)
* @see org.eclipse.etrice.runtime.java.messaging.IMessageService#setThread(java.lang.Thread)
*/
public void setThread(Thread thread) {
this.thread = thread;
thread.setPriority(priority);
}
/* (non-Javadoc)
* @see org.eclipse.etrice.runtime.java.messaging.IMessageService#getThread()
*/
public Thread getThread() {
return thread;
}
protected long getLastMessageTimestamp() {
return lastMessageTimestamp;
}
private class PollingTask implements Runnable{
@Override
public void run() {
if(running){
Message msg = new Message(getMessageDispatcher().getAddress());
receive(msg);
}
}
}
private class PollingThreadFactory implements ThreadFactory{
@Override
public Thread newThread(Runnable arg0) {
Thread thread = new Thread(arg0, getName()+"_PollingThread");
thread.setPriority(priority);
return thread;
}
}
}
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