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27 package org.apache.hc.core5.http2.impl.nio.bootstrap;
28
29 import java.util.concurrent.atomic.AtomicBoolean;
30 import java.util.concurrent.atomic.AtomicReference;
31
32 import org.apache.hc.core5.concurrent.Cancellable;
33 import org.apache.hc.core5.concurrent.CancellableDependency;
34
35 final class CancellableExecution implements CancellableDependency {
36
37 private final AtomicBoolean cancelled;
38 private final AtomicReference<Cancellable> dependencyRef;
39
40 CancellableExecution() {
41 this.cancelled = new AtomicBoolean(false);
42 this.dependencyRef = new AtomicReference<>(null);
43 }
44
45 @Override
46 public void setDependency(final Cancellable cancellable) {
47 dependencyRef.set(cancellable);
48 if (cancelled.get()) {
49 final Cancellable dependency = dependencyRef.getAndSet(null);
50 if (dependency != null) {
51 dependency.cancel();
52 }
53 }
54 }
55
56 @Override
57 public boolean isCancelled() {
58 return cancelled.get();
59 }
60
61 @Override
62 public boolean cancel() {
63 if (cancelled.compareAndSet(false, true)) {
64 final Cancellable dependency = dependencyRef.getAndSet(null);
65 if (dependency != null) {
66 dependency.cancel();
67 }
68 return true;
69 }
70 return false;
71 }
72
73 }