Package co.paralleluniverse.strands.dataflow

Class Val<V>

java.lang.Object

co.paralleluniverse.strands.dataflow.Val<V>

All Implemented Interfaces:

java.util.concurrent.Future<V>

public class Val<V>
extends java.lang.Object
implements java.util.concurrent.Future<V>

A dataflow constant. Represents a delayed value that can be set at most once, and when read, blocks until a value has been set.

Constructor Summary

Constructors

Constructor	Description
Val()
Val(FiberScheduler scheduler, SuspendableCallable<V> f)	Creates a Val whose value will be the one returned by the given SuspendableCallable, which will be spawned into a new fiber, scheduled by the given FiberScheduler.
Val(SuspendableCallable<V> f)	Creates a Val whose value will be the one returned by the given SuspendableCallable, which will be spawned into a new fiber.

Method Summary

Modifier and Type	Method	Description
boolean	cancel(boolean mayInterruptIfRunning)	Throws UnsupportedOperationException.
V	get()	Returns the delayed value, blocking until it has been set.
V	get(long timeout, java.util.concurrent.TimeUnit unit)	Returns the delayed value, blocking until it has been set, but no longer than the given timeout.
V	get(Timeout timeout)
protected SimpleConditionSynchronizer	getSync()
boolean	isCancelled()
boolean	isDone()
void	set(V value)	Sets the value.
void	setException(java.lang.Throwable t)	Sets an exception that will be thrown by get, wrapped by RuntimeExecutionException.

Methods inherited from class java.lang.Object

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

Constructor Detail

Val

public Val(SuspendableCallable<V> f)

Creates a Val whose value will be the one returned by the given SuspendableCallable, which will be spawned into a new fiber.

Parameters:

f - The function that will compute this Val's value in a newly spawned fiber

Val

public Val(FiberScheduler scheduler,
           SuspendableCallable<V> f)

Creates a Val whose value will be the one returned by the given SuspendableCallable, which will be spawned into a new fiber, scheduled by the given FiberScheduler.

Parameters:

scheduler - the scheduler in which the new fiber will be spawned.

f - The function that will compute this Val's value in a newly spawned fiber

Val

public Val()

Method Detail

set

public final void set(V value)

Sets the value. If the value has already been set (or if a function has been supplied to the constructor), this method will throw an IllegalStateException. However, you should not rely on this behavior, as the implementation is free to silently ignore additional attempts to set the value.

Parameters:

value - the value

Throws:

java.lang.IllegalStateException - if the value has already been set.

setException

public final void setException(java.lang.Throwable t)

Sets an exception that will be thrown by get, wrapped by RuntimeExecutionException.

Parameters:

t - the exception

Throws:

java.lang.IllegalStateException - if the value has already been set.

isDone

public boolean isDone()

Specified by:

isDone in interface java.util.concurrent.Future<V>

getSync

protected SimpleConditionSynchronizer getSync()

get

@Suspendable
public V get()
      throws java.lang.InterruptedException

Returns the delayed value, blocking until it has been set.

Specified by:

get in interface java.util.concurrent.Future<V>

Returns:

the value

Throws:

java.lang.InterruptedException

get

@Suspendable
public V get(long timeout,
             java.util.concurrent.TimeUnit unit)
      throws java.lang.InterruptedException,
             java.util.concurrent.TimeoutException

Returns the delayed value, blocking until it has been set, but no longer than the given timeout.

Specified by:

get in interface java.util.concurrent.Future<V>

Parameters:

timeout - The maximum duration to block waiting for the value to be set.

unit - The time unit of the timeout value.

Returns:

the value

Throws:

java.util.concurrent.TimeoutException - if the timeout expires before the value is set.

java.lang.InterruptedException

get

@Suspendable
public V get(Timeout timeout)
      throws java.lang.InterruptedException,
             java.util.concurrent.TimeoutException

Throws:

java.lang.InterruptedException

java.util.concurrent.TimeoutException

cancel

public boolean cancel(boolean mayInterruptIfRunning)

Throws UnsupportedOperationException.

Specified by:

cancel in interface java.util.concurrent.Future<V>

isCancelled

public boolean isCancelled()

Specified by:

isCancelled in interface java.util.concurrent.Future<V>