71 lines
1.5 KiB
Java
71 lines
1.5 KiB
Java
// lowlevel/SyncOnObject.java
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// (c)2021 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://OnJava8.com for more book information.
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// Synchronizing on another object
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import java.util.*;
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import java.util.stream.*;
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import java.util.concurrent.*;
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import onjava.Nap;
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class DualSynch {
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ConcurrentLinkedQueue<String> trace =
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new ConcurrentLinkedQueue<>();
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public synchronized void f(boolean nap) {
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for(int i = 0; i < 5; i++) {
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trace.add(String.format("f() " + i));
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if(nap) new Nap(0.01);
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}
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}
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private Object syncObject = new Object();
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public void g(boolean nap) {
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synchronized(syncObject) {
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for(int i = 0; i < 5; i++) {
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trace.add(String.format("g() " + i));
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if(nap) new Nap(0.01);
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}
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}
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}
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}
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public class SyncOnObject {
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static void test(boolean fNap, boolean gNap) {
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DualSynch ds = new DualSynch();
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List<CompletableFuture<Void>> cfs =
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Arrays.stream(new Runnable[] {
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() -> ds.f(fNap), () -> ds.g(gNap) })
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.map(CompletableFuture::runAsync)
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.collect(Collectors.toList());
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cfs.forEach(CompletableFuture::join);
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ds.trace.forEach(System.out::println);
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}
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public static void main(String[] args) {
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test(true, false);
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System.out.println("****");
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test(false, true);
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}
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}
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/* Output:
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f() 0
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g() 0
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g() 1
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g() 2
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g() 3
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g() 4
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f() 1
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f() 2
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f() 3
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f() 4
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****
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f() 0
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g() 0
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f() 1
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f() 2
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f() 3
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f() 4
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g() 1
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g() 2
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g() 3
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g() 4
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*/
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