JMeter example source code file (SyncTimer.java)

This example JMeter source code file (SyncTimer.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - JMeter tags/keywords

abstracttestelement, interruptedexception, interruptedexception, io, logger, object, object, override, serializable, serializable, synctimer, synctimer, testbean, timer

The JMeter SyncTimer.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 */

package org.apache.jmeter.timers;

import java.io.Serializable;

import org.apache.jmeter.testbeans.TestBean;
import org.apache.jmeter.testelement.AbstractTestElement;
import org.apache.jmeter.threads.JMeterContextService;
import org.apache.jorphan.logging.LoggingManager;
import org.apache.log.Logger;

/**
 * The purpose of the SyncTimer is to block threads until X number of threads
 * have been blocked, and then they are all released at once. A SyncTimer can
 * thus create large instant loads at various points of the test plan.
 *
 */
public class SyncTimer extends AbstractTestElement implements Timer, Serializable, TestBean {
    private static final long serialVersionUID = 2;

    private static final Logger log = LoggingManager.getLoggerForClass();

    // Must be an Object so it will be shared between threads
    private int[] timerCounter = new int[] { 0 };

    private transient Object sync = new Object();

    private int groupSize;

    // Ensure transient object is created by the server
    private Object readResolve(){
        sync = new Object();
        return this;
    }

    /**
     * @return Returns the numThreads.
     */
    public int getGroupSize() {
        return groupSize;
    }

    /**
     * @param numThreads
     *            The numThreads to set.
     */
    public void setGroupSize(int numThreads) {
        this.groupSize = numThreads;
    }

    /**
     * {@inheritDoc}
     */
    public long delay() {
        synchronized (sync) {
            timerCounter[0]++;
            final int groupSz = getGroupSize();
            final int count = timerCounter[0];
            if (
                (groupSz == 0 && count >= JMeterContextService.getNumberOfThreads())
                ||
                (groupSz > 0 && count >= groupSz)
                ) {
                sync.notifyAll();
            } else {
                try {
                    sync.wait();
                } catch (InterruptedException e) {
                    log.warn(e.getLocalizedMessage());
                }
            }
        }
        return 0;
    }

    /**
     * We have to control the cloning process because we need some cross-thread
     * communication if our synctimers are to be able to determine when to block
     * and when to release.
     */
    @Override
    public Object clone() {
        SyncTimer newTimer = (SyncTimer) super.clone();
        newTimer.timerCounter = timerCounter;
        newTimer.sync = sync;
        return newTimer;
    }

}