counter2.java

来自「Java 程序设计源码 只提供了部分」· Java 代码 · 共 109 行

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

class SeparateSubTask extends Thread {
  private int count = 0;
  private Counter2 c2;
  private boolean runFlag = true;

  public SeparateSubTask(Counter2 c2) {
    this.c2 = c2;
    start();
  }

  public void invertFlag() {
    if(runFlag) {
      runFlag = !runFlag;
    }
  }

  public void run() {
    while(true) {
      try {
        sleep(100);
      }
      catch(InterruptedException e) {

        }

      if(runFlag) {
       c2.t.setText(Integer.toString(count++));
      }
    }
  }
}
//以下内容，引用自 Counter
public class Counter2 extends Applet {
  //private int count = 0;
  private SeparateSubTask sst = null;
  private Button
      onOff = new Button("Stop count"),
      start = new Button("Start count");

  TextField t = new TextField(10);
  //private boolean runFlag = true;

  public void init() {
    add(t);
    start.addActionListener(new StartL());
    add(start);
    onOff.addActionListener(new OnOffL());
    add(onOff);
  }

  /**
   * public void go() {
       while(true) {
         try {
          Thread.currentThread().sleep(100);
         }
         catch(InterruptedException ie) {
           if(runFlag) {
             t.setText(Integer.toString(count++));
           }
         }
        }
      }
   */


    class StartL implements ActionListener {
      public void actionPerformed(ActionEvent e) {
        //已经不采用 go() 方法了;

        if(sst == null) {
          sst = new SeparateSubTask(Counter2.this);
        }
      }
    }

    class OnOffL implements ActionListener {
      public void actionPerformed(ActionEvent e) {
        if(sst != null) {
          sst.invertFlag();
        }
         sst = null;
      }
    }

    public static void main(String[] args) {
      Counter2 applet = new Counter2();

      Frame aFrame = new Frame("Counter");

      aFrame.addWindowListener (new WindowAdapter(){
        public void windowClosing(WindowEvent e) {
          System.exit(0);
        }
      });

      aFrame.add(applet, BorderLayout.CENTER);
      aFrame.setSize(300, 200);
      applet.init();
      applet.start();
      aFrame.setVisible(true);
    }
  }