tester.java

thinking in java 书中源码 第四版

//: concurrency/Tester.java
// Framework to test performance of concurrency containers.
import java.util.concurrent.*;
import net.mindview.util.*;

public abstract class Tester<C> {
  static int testReps = 10;
  static int testCycles = 1000;
  static int containerSize = 1000;
  abstract C containerInitializer();
  abstract void startReadersAndWriters();
  C testContainer;
  String testId;
  int nReaders;
  int nWriters;
  volatile long readResult = 0;
  volatile long readTime = 0;
  volatile long writeTime = 0;
  CountDownLatch endLatch;
  static ExecutorService exec =
    Executors.newCachedThreadPool();
  Integer[] writeData;
  Tester(String testId, int nReaders, int nWriters) {
    this.testId = testId + " " +
      nReaders + "r " + nWriters + "w";
    this.nReaders = nReaders;
    this.nWriters = nWriters;
    writeData = Generated.array(Integer.class,
      new RandomGenerator.Integer(), containerSize);
    for(int i = 0; i < testReps; i++) {
      runTest();
      readTime = 0;
      writeTime = 0;
    }
  }
  void runTest() {
    endLatch = new CountDownLatch(nReaders + nWriters);
    testContainer = containerInitializer();
    startReadersAndWriters();
    try {
      endLatch.await();
    } catch(InterruptedException ex) {
      System.out.println("endLatch interrupted");
    }
    System.out.printf("%-27s %14d %14d\n",
      testId, readTime, writeTime);
    if(readTime != 0 && writeTime != 0)
      System.out.printf("%-27s %14d\n",
        "readTime + writeTime =", readTime + writeTime);
  }
  abstract class TestTask implements Runnable {
    abstract void test();
    abstract void putResults();
    long duration;
    public void run() {
      long startTime = System.nanoTime();
      test();
      duration = System.nanoTime() - startTime;
      synchronized(Tester.this) {
        putResults();
      }
      endLatch.countDown();
    }
  }
  public static void initMain(String[] args) {
    if(args.length > 0)
      testReps = new Integer(args[0]);
    if(args.length > 1)
      testCycles = new Integer(args[1]);
    if(args.length > 2)
      containerSize = new Integer(args[2]);
    System.out.printf("%-27s %14s %14s\n",
      "Type", "Read time", "Write time");
  }
} ///:~