AbstractQNetsimEngineRunner.java

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/* *********************************************************************** *
 * project: org.matsim.*
 * QSimEngineRunner.java
 *                                                                         *
 * *********************************************************************** *
 *                                                                         *
 * copyright       : (C) 2009 by the members listed in the COPYING,        *
 *                   LICENSE and WARRANTY file.                            *
 * email           : info at matsim dot org                                *
 *                                                                         *
 * *********************************************************************** *
 *                                                                         *
 *   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 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *   See also COPYING, LICENSE and WARRANTY file                           *
 *                                                                         *
 * *********************************************************************** */

package org.matsim.core.mobsim.qsim.qnetsimengine;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

import org.matsim.core.mobsim.qsim.QSim;

abstract class AbstractQNetsimEngineRunner extends NetElementActivationRegistry {

    private double time = 0.0;

    /*
     * This needs to be thread-safe since QNodes could be activated concurrently
     * from multiple threads. In previous implementations, this data structure was
     * a Map since it was possible that the same node was activated concurrently.
     * Now, the implementation of the QNode was adapted in a way that this is not
     * possible anymore.
     * cdobler, sep'14
     */
    private final Queue<QNodeI> nodesQueue = new ConcurrentLinkedQueue<>();

    /*
     * Needs not to be thread-safe since links are only activated from nodes which
     * are handled (by design) from links handled by the same thread. Therefore,
     * no concurrent add operation can occur.
     * cdobler, sep'14
     */
    private final List<QLinkI> linksList = new LinkedList<>();

    /*
     * Ensure that nodes and links are only activate during times where we expect it.
     * Otherwise this could result in unpredictable behavior. Therefore we throw
     * an exception then.
     * Doing so allows us adding nodes and links directly to the nodesQueue respectively
     * the linksList. Previously, we had to cache them in other data structures and copy
     * them at a later point in time.
     * cdobler, sep'14
     */
    private boolean lockNodes = false;
    private boolean lockLinks = false;

    /*package*/ long[] runTimes;
    private long startTime = 0;
    {   
        if (QSim.analyzeRunTimes) runTimes = new long[QNetsimEngineWithThreadpool.numObservedTimeSteps];
        else runTimes = null;
    }

    /*package*/ final void setTime(final double t) {
        time = t;
    }

    public abstract void afterSim() ;

    protected void moveNodes() {
        boolean remainsActive;
        this.lockNodes = true;
        QNodeI node;
        Iterator<QNodeI> simNodes = this.nodesQueue.iterator();
        while (simNodes.hasNext()) {
            node = simNodes.next();
            remainsActive = node.doSimStep(time);
            if (!remainsActive) simNodes.remove();
        }
        this.lockNodes = false;
    }
    
    protected final void moveLinks() {
        boolean remainsActive;
        lockLinks = true;
        QLinkI link;
        ListIterator<QLinkI> simLinks = this.linksList.listIterator();
        while (simLinks.hasNext()) {
            link = simLinks.next();

            remainsActive = link.doSimStep();

            if (!remainsActive) simLinks.remove();
        }
        lockLinks = false;
    }

    /*
     * This method is only called while links are NOT "moved", i.e. their
     * doStimStep(...) methods are called. To ensure that, we  use a boolean lock.
     * cdobler, sep'14
     */
    @Override
    protected final void registerLinkAsActive(QLinkI link) {
        if (!lockLinks) linksList.add(link);
        else throw new RuntimeException("Tried to activate a QLink at a time where this was not allowed. Aborting!");
    }

    @Override
    public final int getNumberOfSimulatedLinks() {
        return this.linksList.size();
    }

    /*
     * This method is only called while nodes are NOT "moved", i.e. their
     * doStimStep(...) methods are called. To ensure that, we  use a boolean lock.
     * cdobler, sep'14
     */
    @Override
    protected final void registerNodeAsActive(QNodeI node) {
        if (!this.lockNodes) this.nodesQueue.add(node);
        else throw new RuntimeException("Tried to activate a QNode at a time where this was not allowed. Aborting!");
    }

    /*
     * Note that the size() method is O(n) for a ConcurrentLinkedQueue as used
     * for the nodesQueue. However, this method is only called once every simulated
     * hour for the log message. Therefore, it should be okay.
     * cdobler, sep'14
     */
    @Override
    public final int getNumberOfSimulatedNodes() {
        return this.nodesQueue.size();
    }

    protected final void startMeasure() {
        if (QSim.analyzeRunTimes) this.startTime = System.nanoTime();       
    }

    protected final void endMeasure() {
        if (QSim.analyzeRunTimes) {
            long end = System.nanoTime();
            int bin = (int) this.time;
            if (bin < this.runTimes.length) this.runTimes[bin] = end - this.startTime;
        }
    }
}