MixPlugIn.java

/*******************************************************************************
 * gMix open source project - https://svs.informatik.uni-hamburg.de/gmix/
 * Copyright (C) 2014  SVS
 *
 * This program 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.
 *  
 * This program 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.
 *
 * You should have received a copy of the GNU General Public License 
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *******************************************************************************/
package userGeneratedContent.testbedPlugIns.layerPlugIns.layer3outputStrategy.batchWithTimeout_v0_001;

import java.util.Collections;
import java.util.Vector;
import java.util.concurrent.Callable;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

import staticContent.framework.controller.Implementation;
import staticContent.framework.interfaces.Layer3OutputStrategyMix;
import staticContent.framework.message.MixMessage;
import staticContent.framework.message.Reply;
import staticContent.framework.message.Request;
import staticContent.framework.userDatabase.User;


//Dingledine 2002: Timed Mix
//collects messages until "batchSize" messages are reached or a timeout occurs
//the timeout timer is started when the first message is added to the batch
//and gets canceled as the batch is put out (due to reaching the batch size)
//see also: "ThresholdOrTimedBatch.java"
public class MixPlugIn extends Implementation implements Layer3OutputStrategyMix {

	private SimplexBatchWithTimeout requestBatch;
	private SimplexBatchWithTimeout replyBatch;
	private int TIMEOUT;
	private int BATCH_SIZE;
	
	
	@Override
	public void constructor() {
		this.TIMEOUT = settings.getPropertyAsInt("BATCH_WITH_TIMEOUT_TIMEOUT");
		this.BATCH_SIZE = settings.getPropertyAsInt("BATCH_WITH_TIMEOUT_BATCH_SIZE");
		this.requestBatch = new SimplexBatchWithTimeout(true);
		this.replyBatch = new SimplexBatchWithTimeout(false);
	}

	
	@Override
	public void initialize() {
		// no need to do anything
	}

	
	@Override
	public void begin() {
		// no need to do anything
	}

	
	@Override
	public void addRequest(Request request) {
		requestBatch.addMessage((MixMessage)request);
	}


	@Override
	public void addReply(Reply reply) {
		replyBatch.addMessage((MixMessage)reply);
	}
	
	
	public class SimplexBatchWithTimeout implements Callable<SimplexBatchWithTimeout> {

		private boolean isRequestBatch;
		private Vector<MixMessage> collectedMessages;
		private volatile long lastOutput;
		private ScheduledThreadPoolExecutor scheduler;
		private ScheduledFuture<?> currentTimer;
		
		
		public SimplexBatchWithTimeout(boolean isRequestBatch) {
			this.collectedMessages = new Vector<MixMessage>(BATCH_SIZE);
			this.isRequestBatch = isRequestBatch;
			this.scheduler = new ScheduledThreadPoolExecutor(1);
		}
		
		
		public void addMessage(MixMessage mixMessage) {
			synchronized (this) {
				collectedMessages.add(mixMessage);
				if (collectedMessages.size() == 1) {
					currentTimer = scheduler.schedule(this, TIMEOUT, TimeUnit.MILLISECONDS);
					lastOutput = clock.getTime();
				} else if (collectedMessages.size() >= BATCH_SIZE)
					putOutMessages();
			}
		}

		
		public void putOutMessages() {
			synchronized (this) {
				Collections.sort(collectedMessages);
				if (isRequestBatch) {
					for (MixMessage m: collectedMessages)
						anonNode.putOutRequest((Request)m);
				} else {
					for (MixMessage m: collectedMessages)
						anonNode.putOutReply((Reply)m);
				}
				this.collectedMessages = new Vector<MixMessage>(BATCH_SIZE);
				if (currentTimer != null)
					currentTimer.cancel(false);
				this.lastOutput = clock.getTime();
			}	
		}


		@Override
		public SimplexBatchWithTimeout call() throws Exception {
			if (clock.getTime() - lastOutput >= TIMEOUT) {
				putOutMessages();
			}
			return this;
		}
			
	}
	
	
	@Override
	public int getMaxSizeOfNextWrite() {
		return super.recodingLayerMix.getMaxSizeOfNextReply();
	}


	@Override
	public int getMaxSizeOfNextRead() {
		return super.recodingLayerMix.getMaxSizeOfNextRequest();
	}


	@Override
	public void write(User user, byte[] data) {
		Reply reply = MixMessage.getInstanceReply(data, user); 
		reply.isFirstReplyHop = true;
		transportLayerMix.addLayer4Header(reply);
		anonNode.forwardToLayer2(reply);
	}
	
}