CollectionTest.java Source code

Introduction

Here is the source code for CollectionTest.java

Source

/*
Java Threads, 3rd Edition
By Scott Oaks, Henry Wong
3rd Edition September 2004 
ISBN: 0-596-00782-5
    
*/

import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.*;

public class CollectionTest {
    static int nLoops;

    public static void main(String[] args) {

        nLoops = 10000;
        doTest(new Vector());
        doTest(new ArrayList());
        doTest(Collections.synchronizedList(new ArrayList()));
        nLoops = Integer.parseInt(args[0]);

        System.out.println("Starting synchronized vector test");
        cleanGC();
        Timestamp syncTS = new Timestamp();
        doTest(new Vector());
        syncTS.stop();
        System.out.println("Synchronized vector took " + syncTS);

        System.out.println("Starting unsynchronized vector test");
        cleanGC();
        Timestamp unsyncTS = new Timestamp();
        unsyncTS.stop();
        System.out.println("Unsynchronized vector took " + unsyncTS);

        double d = ((double) (syncTS.elapsedTime() - unsyncTS.elapsedTime())) / nLoops;
        System.out.println("Unsynchronized operation saves " + d + " " + syncTS.units() + " per call");

        System.out.println("Starting synchronized array list test");
        cleanGC();
        syncTS = new Timestamp();
        doTest(Collections.synchronizedList(new ArrayList()));
        syncTS.stop();
        System.out.println("Synchronized array list took " + syncTS);

        System.out.println("Starting unsynchronized array list test");
        cleanGC();
        unsyncTS = new Timestamp();
        doTest(new ArrayList());
        unsyncTS.stop();
        System.out.println("Unsynchronized aray list took " + unsyncTS);

        d = ((double) (syncTS.elapsedTime() - unsyncTS.elapsedTime())) / nLoops;
        System.out.println("Unsynchronized operation saves " + d + " " + syncTS.units() + " per call");
    }

    static void cleanGC() {
        System.gc();
        System.runFinalization();
        System.gc();
    }

    static void doTest(List l) {
        Integer n = new Integer(0);
        for (int i = 0; i < nLoops; i++)
            l.add(n);
    }
}

class Timestamp {

    private long startTime;

    private long stopTime;

    private boolean stopped = false;

    private TimeUnit ts;

    public Timestamp() {
        this(TimeUnit.NANOSECONDS);
    }

    public Timestamp(TimeUnit ts) {
        this.ts = ts;
        start();
    }

    public void start() {
        startTime = System.nanoTime();
        stopped = false;
    }

    public void stop() {
        stopTime = System.nanoTime();
        stopped = true;
    }

    public long elapsedTime() {
        if (!stopped)
            throw new IllegalStateException("Timestamp not stopped");
        return ts.convert(stopTime - startTime, TimeUnit.NANOSECONDS);
    }

    public String toString() {
        try {
            return elapsedTime() + " " + ts;
        } catch (IllegalStateException ise) {
            return "Timestamp (not stopped)";
        }
    }

    public String units() {
        return ts.toString();
    }
}