56 lines
1.7 KiB
Java
56 lines
1.7 KiB
Java
// concurrency/Daemons.java
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// ©2016 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://mindviewinc.com/Books/OnJava/ for more book information.
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// Daemon threads spawn other daemon threads.
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import java.util.concurrent.*;
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class Daemon implements Runnable {
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private Thread[] t = new Thread[10];
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@Override
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public void run() {
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for(int i = 0; i < t.length; i++) {
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t[i] = new Thread(new DaemonSpawn());
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t[i].start();
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System.out.print("DaemonSpawn " + i + " started, ");
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}
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for(int i = 0; i < t.length; i++)
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System.out.print("t[" + i + "].isDaemon() = " +
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t[i].isDaemon() + ", ");
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while(true)
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Thread.yield();
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}
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}
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class DaemonSpawn implements Runnable {
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@Override
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public void run() {
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while(true)
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Thread.yield();
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}
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}
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public class Daemons {
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public static void main(String[] args) throws Exception {
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Thread d = new Thread(new Daemon());
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d.setDaemon(true);
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d.start();
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System.out.print("d.isDaemon() = " + d.isDaemon() + ", ");
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// Allow the daemon threads to
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// finish their startup processes:
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TimeUnit.SECONDS.sleep(1);
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}
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}
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/* Output:
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d.isDaemon() = true, DaemonSpawn 0 started, DaemonSpawn 1
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started, DaemonSpawn 2 started, DaemonSpawn 3 started,
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DaemonSpawn 4 started, DaemonSpawn 5 started, DaemonSpawn 6
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started, DaemonSpawn 7 started, DaemonSpawn 8 started,
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DaemonSpawn 9 started, t[0].isDaemon() = true,
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t[1].isDaemon() = true, t[2].isDaemon() = true,
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t[3].isDaemon() = true, t[4].isDaemon() = true,
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t[5].isDaemon() = true, t[6].isDaemon() = true,
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t[7].isDaemon() = true, t[8].isDaemon() = true,
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t[9].isDaemon() = true,
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*/
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