72 lines
1.7 KiB
Java
72 lines
1.7 KiB
Java
// threads/ThreadLocalVariableHolder.java
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// (c)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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// Automatically giving each thread its own storage
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import java.util.concurrent.*;
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import java.util.*;
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class Accessor implements Runnable {
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private final int id;
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public Accessor(int idn) { id = idn; }
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@Override
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public void run() {
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while(!Thread.currentThread().isInterrupted()) {
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ThreadLocalVariableHolder.increment();
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System.out.println(this);
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Thread.yield();
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}
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}
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@Override
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public String toString() {
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return "#" + id + ": " +
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ThreadLocalVariableHolder.get();
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}
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}
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public class ThreadLocalVariableHolder {
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private static ThreadLocal<Integer> value =
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new ThreadLocal<Integer>() {
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private SplittableRandom rand = new SplittableRandom(47);
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@Override
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protected synchronized Integer initialValue() {
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return rand.nextInt(10000);
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}
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};
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public static void increment() {
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value.set(value.get() + 1);
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}
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public static int get() { return value.get(); }
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public static void
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main(String[] args) throws Exception {
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ExecutorService es = Executors.newCachedThreadPool();
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for(int i = 0; i < 5; i++)
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es.execute(new Accessor(i));
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TimeUnit.SECONDS.sleep(3); // Run for a while
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es.shutdownNow(); // All Accessors will quit
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}
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}
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/* Output: (First and last 10 Lines)
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#2: 9259
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#1: 962
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#3: 1862
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#4: 6694
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#0: 556
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#4: 6695
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#4: 6696
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#3: 1863
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#1: 963
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#2: 9260
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________...________...________...________...________
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#3: 3791
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#2: 11096
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#4: 8402
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#4: 8403
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#2: 11097
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#3: 3792
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#0: 2637
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#1: 3032
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#4: 8404
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#2: 11098
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*/
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