使用 ThreadLocal 实现的计数器测试，threadlocal计数器,package tuni

使用 ThreadLocal 实现的计数器测试，threadlocal计数器,package tuni

package tuning.threads;public class CounterTest  extends Thread{  private static Object LOCK1 = new Object();  private static Object LOCK2 = new Object();  private static long startTime = -1;  static int REPEAT;  static int numThreads = 0;  static boolean Go = false;  private static int NUMBER_OF_THREADS = 4;  //instance variable to specify which thread we are.  int num;  //Create a thread, assigning a unique value for the thread.  //The value is used to index into the global array of counters  //in Counter3 class.  public CounterTest(int threadnum)  {    super();    num = threadnum;  }  synchronized static void incThreads() {numThreads++;}  synchronized static void decThreads() {numThreads--;}  static int getNumThreads() {return numThreads;}  //And main which forks four threads, and run() which adds the value 1 to the Counter,  //500,000 times consecutively, with timing code to determine how long from start of first  //thread to termination of the last.  public static void main(String[] args)  {    int tmpREPEAT = (args.length > 0) ? Integer.parseInt(args[0]) : 10000000;    if (args.length < 2)    {      //don't use this if we have two or more args      REPEAT = 10000;      test();    }    REPEAT = tmpREPEAT;    test();  }  public static void test()  {    for (int i = 0; i < NUMBER_OF_THREADS; i++)      (new CounterTest(i)).start();    runOneTest();    runOneTest();    runOneTest();  }  public static void runOneTest()  {    //wait until all threads are ready to run    while(getNumThreads() < NUMBER_OF_THREADS)      try{Thread.sleep(10);}catch(InterruptedException e){}    //tell the threads to go    synchronized (LOCK1) {LOCK1.notifyAll();}    //wait for them all to stop    while(getNumThreads() > 0)      try{Thread.sleep(100);}catch(InterruptedException e){}    //reset the start time    startTime = -1;    //All threads have stopped now, so we can release them    synchronized (LOCK2) {LOCK2.notifyAll();}  }  public static void waitForGo(String mess)  {    //Register that we are ready to run    incThreads();    //wait until told to start, so that we can start all    //the threads at approximately the same time.    synchronized(LOCK1)    {      try {LOCK1.wait();}      catch (InterruptedException e) {}    }    System.out.println("Starting test for " + mess);    //Set the start time only once at the beginning    //of the first thread to start.    setStartTime();  }  public synchronized static void setStartTime()  {    //only sets the start time once    if (startTime == -1)      startTime = System.currentTimeMillis();  }  public static void stop(String mess)  {    //print time and count for every thread.    //Only the last thread to terminate gives full values.    System.out.println(mess + " time: " + (System.currentTimeMillis()-startTime));    decThreads();    //Wait until the main threads knows that we've finished    synchronized(LOCK2)    {      try {LOCK2.wait();}      catch (InterruptedException e) {}    }  }  public void run()  {    Counter1.initialize(0);    waitForGo("Counter1");    for (int i = REPEAT; i > 0; i--)      Counter1.addAmount(0, 1);    stop("Counter1 count: " + Counter1.getAmount(0));    Counter2.initialize(0);    waitForGo("Counter2");    for (int i = REPEAT; i > 0; i--)      Counter2.addAmount(0, 1);    stop("Counter2 count: " + Counter2.getAmount(0));    Counter3.initialize(this);    waitForGo("Counter3");    for (int i = REPEAT; i > 0; i--)      Counter3.addAmount(0, 1);    stop("Counter3 count: " + Counter3.getAmount(0));  }}//该片段来自于http://byrx.net