com.google.common.util.concurrent
Class AbstractCheckedFuture<V,E extends Exception>

java.lang.Object
  com.google.common.util.concurrent.AbstractCheckedFuture<V,E>

All Implemented Interfaces:

CheckedFuture<V,E>, ListenableFuture<V>, Future<V>

public abstract class AbstractCheckedFuture<V,E extends Exception>
extends Object
implements CheckedFuture<V,E>

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

Since:

2009.09.15 tentative

Author:

Sven Mawson

Field Summary

protected ListenableFuture<V>

delegate The delegate, used to pass along all our methods.

Constructor Summary

protected

AbstractCheckedFuture(ListenableFuture<V> delegate) Constructs an AbstractCheckedFuture that wraps a delegate.

Method Summary

void	addListener(Runnable listener, Executor exec) Adds a listener and executor to the ListenableFuture.
boolean	cancel(boolean mayInterruptIfRunning)
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.
V	get()
V	get(long timeout, TimeUnit unit)
boolean	isCancelled()
boolean	isDone()
protected abstract E	mapException(Exception e) Translate from an InterruptedException, CancellationException or ExecutionException to an exception of type E.

Methods inherited from class java.lang.Object

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

Field Detail

delegate

protected final ListenableFuture<V> delegate

The delegate, used to pass along all our methods.

Constructor Detail

AbstractCheckedFuture

protected AbstractCheckedFuture(ListenableFuture<V> delegate)

Constructs an AbstractCheckedFuture that wraps a delegate.

Method Detail

mapException

protected abstract E mapException(Exception e)

Translate from an InterruptedException, CancellationException or ExecutionException to an exception of type E. Subclasses must implement the mapping themselves. The e parameter can be an instance of InterruptedException, CancellationException, or ExecutionException.

checkedGet

public V checkedGet()
             throws E extends Exception

Description copied from interface: CheckedFuture

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

Specified by:

checkedGet in interface CheckedFuture<V,E extends Exception>

Returns:

the result of executing the future.

Throws:

E - on interruption, cancellation or execution exceptions.

E extends Exception

checkedGet

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

Description copied from interface: CheckedFuture

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.

Specified by:

checkedGet in interface CheckedFuture<V,E extends Exception>

Returns:

the result of executing the future.

Throws:

TimeoutException - if retrieving the result timed out.

E - on interruption, cancellation or execution exceptions.

E extends Exception

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Specified by:

cancel in interface Future<V>

isCancelled

public boolean isCancelled()

Specified by:

isCancelled in interface Future<V>

isDone

public boolean isDone()

Specified by:

isDone in interface Future<V>

get

public V get()
      throws InterruptedException,
             ExecutionException

Specified by:

get in interface Future<V>

Throws:

InterruptedException

ExecutionException

get

public V get(long timeout,
             TimeUnit unit)
      throws InterruptedException,
             ExecutionException,
             TimeoutException

Specified by:

get in interface Future<V>

Throws:

InterruptedException

ExecutionException

TimeoutException

addListener

public void addListener(Runnable listener,
                        Executor exec)

Description copied from interface: ListenableFuture

Adds a listener and executor to the ListenableFuture. The listener will be passed to the executor for execution when the Future's computation is complete.

There is no guaranteed ordering of execution of listeners, they may get called in the order they were added and they may get called out of order, but any listener added through this method is guaranteed to be called once the computation is complete.

Specified by:

addListener in interface ListenableFuture<V>

Parameters:

listener - the listener to run when the computation is complete.

exec - the executor to run the listener in.