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SettableListenableFuture consistently tracks cancellation state

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Issue: SPR-15202
(cherry picked from commit 9666fcc)
This commit is contained in:
Juergen Hoeller
2017-01-31 15:57:52 +01:00
parent 3ef6697536
commit dec1c93b24
2 changed files with 125 additions and 67 deletions
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63
spring-core/src/main/java/org/springframework/util/concurrent/SettableListenableFuture.java
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@@ -1,5 +1,5 @@
/*
* Copyright 2002-2016 the original author or authors.
* Copyright 2002-2017 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -27,13 +27,14 @@ import org.springframework.util.ReflectionUtils;
/**
* A {@link org.springframework.util.concurrent.ListenableFuture ListenableFuture}
* whose value can be set via {@link #set(Object)} or
* {@link #setException(Throwable)}. It may also be cancelled.
* whose value can be set via {@link #set(T)} or {@link #setException(Throwable)}.
* It may also be cancelled.
*
* <p>Inspired by {@code com.google.common.util.concurrent.SettableFuture}.
*
* @author Mattias Severson
* @author Rossen Stoyanchev
* @author Juergen Hoeller
* @since 4.1
*/
public class SettableListenableFuture<T> implements ListenableFuture<T> {
@@ -92,8 +93,8 @@ public class SettableListenableFuture<T> implements ListenableFuture<T> {
@Override
public boolean cancel(boolean mayInterruptIfRunning) {
this.settableTask.setCancelled();
boolean cancelled = this.listenableFuture.cancel(mayInterruptIfRunning);
boolean cancelled = this.settableTask.setCancelled();
this.listenableFuture.cancel(mayInterruptIfRunning);
if (cancelled && mayInterruptIfRunning) {
interruptTask();
}
@@ -102,21 +103,21 @@ public class SettableListenableFuture<T> implements ListenableFuture<T> {
@Override
public boolean isCancelled() {
return this.listenableFuture.isCancelled();
return this.settableTask.isCancelled();
}
@Override
public boolean isDone() {
return this.listenableFuture.isDone();
return this.settableTask.isDone();
}
/**
* Retrieve the value.
* <p>Will return the value if it has been set via {@link #set(Object)},
* throw an {@link java.util.concurrent.ExecutionException} if it has been
* set via {@link #setException(Throwable)} or throw a
* {@link java.util.concurrent.CancellationException} if it has been cancelled.
* @return The value associated with this future.
* <p>This method returns the value if it has been set via {@link #set(Object)},
* throws an {@link java.util.concurrent.ExecutionException} if an exception has
* been set via {@link #setException(Throwable)}, or throws a
* {@link java.util.concurrent.CancellationException} if the future has been cancelled.
* @return the value associated with this future
*/
@Override
public T get() throws InterruptedException, ExecutionException {
@@ -125,13 +126,13 @@ public class SettableListenableFuture<T> implements ListenableFuture<T> {
/**
* Retrieve the value.
* <p>Will return the value if it has been set via {@link #set(Object)},
* throw an {@link java.util.concurrent.ExecutionException} if it has been
* set via {@link #setException(Throwable)} or throw a
* {@link java.util.concurrent.CancellationException} if it has been cancelled.
* @param timeout the maximum time to wait.
* @param unit the time unit of the timeout argument.
* @return The value associated with this future.
* <p>This method returns the value if it has been set via {@link #set(Object)},
* throws an {@link java.util.concurrent.ExecutionException} if an exception has
* been set via {@link #setException(Throwable)}, or throws a
* {@link java.util.concurrent.CancellationException} if the future has been cancelled.
* @param timeout the maximum time to wait
* @param unit the unit of the timeout argument
* @return the value associated with this future
*/
@Override
public T get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException {
@@ -142,7 +143,7 @@ public class SettableListenableFuture<T> implements ListenableFuture<T> {
* Subclasses can override this method to implement interruption of the future's
* computation. The method is invoked automatically by a successful call to
* {@link #cancel(boolean) cancel(true)}.
* <p>The default implementation does nothing.
* <p>The default implementation is empty.
*/
protected void interruptTask() {
}
@@ -152,26 +153,28 @@ public class SettableListenableFuture<T> implements ListenableFuture<T> {
private static final Object NO_VALUE = new Object();
private static final Object CANCELLED = new Object();
private final AtomicReference<Object> value = new AtomicReference<Object>(NO_VALUE);
private volatile boolean cancelled = false;
public boolean setValue(T value) {
if (this.cancelled) {
return false;
}
return this.value.compareAndSet(NO_VALUE, value);
}
public boolean setException(Throwable exception) {
if (this.cancelled) {
return false;
}
return this.value.compareAndSet(NO_VALUE, exception);
}
public void setCancelled() {
this.cancelled = true;
public boolean setCancelled() {
return this.value.compareAndSet(NO_VALUE, CANCELLED);
}
public boolean isCancelled() {
return (this.value.get() == CANCELLED);
}
public boolean isDone() {
return (this.value.get() != NO_VALUE);
}
@SuppressWarnings("unchecked")