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TestAccess.javaAPI DocExample3418Mon Apr 06 18:10:22 BST 1998None

TestAccess.java

//: TestAccess.java
//////////////////////////////////////////////////
// Copyright (c) Bruce Eckel, 1998
// Source code file from the book "Thinking in Java"
// All rights reserved EXCEPT as allowed by the
// following statements: You can freely use this file
// for your own work (personal or commercial),
// including modifications and distribution in
// executable form only. Permission is granted to use
// this file in classroom situations, including its
// use in presentation materials, as long as the book
// "Thinking in Java" is cited as the source. 
// Except in classroom situations, you cannot copy
// and distribute this code; instead, the sole
// distribution point is http://www.BruceEckel.com 
// (and official mirror sites) where it is
// freely available. You cannot remove this
// copyright and notice. You cannot distribute
// modified versions of the source code in this
// package. You cannot use this file in printed
// media without the express permission of the
// author. Bruce Eckel makes no representation about
// the suitability of this software for any purpose.
// It is provided "as is" without express or implied
// warranty of any kind, including any implied
// warranty of merchantability, fitness for a
// particular purpose or non-infringement. The entire
// risk as to the quality and performance of the
// software is with you. Bruce Eckel and the
// publisher shall not be liable for any damages
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// Bruce Eckel or the publisher be liable for any
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// address for non-code errors found in the book.)
/////////////////////////////////////////////////

// How threads can access other threads
// in a parent thread group

public class TestAccess {
  public static void main(String[] args) {
    ThreadGroup 
      x = new ThreadGroup("x"),
      y = new ThreadGroup(x, "y"),
      z = new ThreadGroup(y, "z");
    Thread
      one = new TestThread1(x, "one"),
      two = new TestThread2(z, "two");
  }
}

class TestThread1 extends Thread {
  private int i;
  TestThread1(ThreadGroup g, String name) {
    super(g, name);
  }
  void f() {
    i++; // modify this thread
    System.out.println(getName() + " f()");
  }
}

class TestThread2 extends TestThread1 {
  TestThread2(ThreadGroup g, String name) {
    super(g, name);
    start();
  }
  public void run() {
    ThreadGroup g =
      getThreadGroup().getParent().getParent();
    g.list();
    Thread[] gAll = new Thread[g.activeCount()];
    g.enumerate(gAll);
    for(int i = 0; i < gAll.length; i++) {
      gAll[i].setPriority(Thread.MIN_PRIORITY);
      ((TestThread1)gAll[i]).f();
    }
    g.list();
  }
} ///:~