com.google.common.util.concurrent

Class AbstractCheckedFuture<V,X extends Exception>

java.lang.Object

com.google.common.collect.ForwardingObject

com.google.common.util.concurrent.ForwardingFuture<V>

com.google.common.util.concurrent.ForwardingListenableFuture<V>

com.google.common.util.concurrent.ForwardingListenableFuture.SimpleForwardingListenableFuture<V>

com.google.common.util.concurrent.AbstractCheckedFuture<V,X>

All Implemented Interfaces:

CheckedFuture<V,X>, ListenableFuture<V>, Future<V>

@Beta
public abstract class AbstractCheckedFuture<V,X extends Exception>
extends ForwardingListenableFuture.SimpleForwardingListenableFuture<V>
implements CheckedFuture<V,X>

A delegating wrapper around a ListenableFuture that adds support for the checkedGet() and checkedGet(long, TimeUnit) methods.

Since:

1.0

Nested Class Summary

Nested classes/interfaces inherited from class com.google.common.util.concurrent.ForwardingListenableFuture

ForwardingListenableFuture.SimpleForwardingListenableFuture<V>

Nested classes/interfaces inherited from class com.google.common.util.concurrent.ForwardingFuture

ForwardingFuture.SimpleForwardingFuture<V>

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AbstractCheckedFuture(ListenableFuture<V> delegate) Constructs an AbstractCheckedFuture that wraps a delegate.

Method Summary

Modifier and Type	Method and Description
V	checkedGet() Exception checking version of Future.get() that will translate InterruptedException, CancellationException and ExecutionException into application-specific exceptions.
V	checkedGet(long timeout, TimeUnit unit) Exception checking version of Future.get(long, TimeUnit) that will translate InterruptedException, CancellationException and ExecutionException into application-specific exceptions.
protected abstract X	mapException(Exception e) Translates from an InterruptedException, CancellationException or ExecutionException thrown by get to an exception of type X to be thrown by checkedGet.

Methods inherited from class com.google.common.util.concurrent.ForwardingListenableFuture.SimpleForwardingListenableFuture

delegate

Methods inherited from class com.google.common.util.concurrent.ForwardingListenableFuture

addListener

Methods inherited from class com.google.common.util.concurrent.ForwardingFuture

cancel, get, get, isCancelled, isDone

Methods inherited from class com.google.common.collect.ForwardingObject

toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.google.common.util.concurrent.ListenableFuture

addListener

Methods inherited from interface java.util.concurrent.Future

cancel, get, get, isCancelled, isDone

Constructor Detail

AbstractCheckedFuture

protected AbstractCheckedFuture(ListenableFuture<V> delegate)

Constructs an AbstractCheckedFuture that wraps a delegate.

Method Detail

mapException

protected abstract X mapException(Exception e)

Translates from an InterruptedException, CancellationException or ExecutionException thrown by get to an exception of type X to be thrown by checkedGet. Subclasses must implement this method.

If e is an InterruptedException, the calling checkedGet method has already restored the interrupt after catching the exception. If an implementation of mapException(Exception) wishes to swallow the interrupt, it can do so by calling Thread.interrupted().

Subclasses may choose to throw, rather than return, a subclass of RuntimeException to allow creating a CheckedFuture that throws both checked and unchecked exceptions.

checkedGet

public V checkedGet()
             throws X extends Exception

Exception checking version of Future.get() that will translate InterruptedException, CancellationException and ExecutionException into application-specific exceptions.

This implementation calls ForwardingFuture.get() and maps that method's standard exceptions to instances of type X using mapException(java.lang.Exception).

In addition, if get throws an InterruptedException, this implementation will set the current thread's interrupt status before calling mapException.

Specified by:

checkedGet in interface CheckedFuture<V,X extends Exception>

Returns:

the result of executing the future.

Throws:

X - if ForwardingFuture.get() throws an InterruptedException, CancellationException, or ExecutionException

X extends Exception

checkedGet

public V checkedGet(long timeout,
                    TimeUnit unit)
             throws TimeoutException,
                    X extends Exception

Exception checking version of Future.get(long, TimeUnit) that will translate InterruptedException, CancellationException and ExecutionException into application-specific exceptions. On timeout this method throws a normal TimeoutException.

This implementation calls ForwardingFuture.get(long, TimeUnit) and maps that method's standard exceptions (excluding TimeoutException, which is propagated) to instances of type X using mapException(java.lang.Exception).

In addition, if get throws an InterruptedException, this implementation will set the current thread's interrupt status before calling mapException.

Specified by:

checkedGet in interface CheckedFuture<V,X extends Exception>

Returns:

the result of executing the future.

Throws:

X - if ForwardingFuture.get() throws an InterruptedException, CancellationException, or ExecutionException

TimeoutException - if retrieving the result timed out.

X extends Exception