LazyDataflowVariable (org.codehaus.gpars)

groovyx.gpars.dataflow.LazyDataflowVariable

Represents a thread-safe single-assignment, multi-read variable with delayed initialization. Each instance of DataflowVariable can be read repeatedly any time using the 'val' property and assigned once in its lifetime using the '<<' operator. Reads preceding assignment will be blocked until the value is assigned. For actors and Dataflow Operators the asynchronous non-blocking variants of the getValAsync() methods can be used. They register the request to read a value and will send a message to the actor or operator once the value is available.
Parameters:
- Type of values to bind with the DataflowVariable
Authors:
Vaclav Pech Date: April 4, 2013

Field Summary

Fields
Modifiers	Name	Description
`private PGroup`	`group`
`private java.util.concurrent.atomic.AtomicBoolean`	`initializationStarted`
`private groovy.lang.Closure<T>`	`initializer`

Inherited fields
Fields inherited from class	Fields
`class DataflowVariable`	`serialVersionUID`
`class DataflowExpression`	`ATTACHMENT, A_DATAFLOW_VARIABLE_CAN_ONLY_BE_ASSIGNED_ONCE_ONLY_RE_ASSIGNMENTS_TO_AN_EQUAL_VALUE_ARE_ALLOWED, CANNOT_FIRE_BIND_ERRORS_THE_THREAD_HAS_BEEN_INTERRUPTED, RESULT, S_INITIALIZED, S_INITIALIZING, S_NOT_INITIALIZED, dummyWaitingThread, error, eventManager, metaClass, serialVersionUID, state, stateUpdater, value, waiting, waitingUpdater`
`class WithSerialId`	`serialHandle, serialVersionUID`

Constructor Summary

Constructors
Constructor and description
`LazyDataflowVariable (groovy.lang.Closure<T> initializer)` Creates a new unbound Lazy Dataflow Variable
`LazyDataflowVariable (PGroup group, groovy.lang.Closure<T> initializer)` Creates a new unbound Lazy Dataflow Variable with specific a PGroup to use for running the initializer

Methods Summary

Methods
Type	Name and description
`java.lang.Throwable`	`getError()` Returns the error bound to the promise
`T`	`getVal()`
`T`	`getVal(long timeout, java.util.concurrent.TimeUnit units)`
`void`	`getValAsync(MessageStream callback)`
`void`	`getValAsync(java.lang.Object attachment, MessageStream callback)`
`private void`	`initialize()`
`boolean`	`isError()` Checks if the promise is bound to an error
`Promise<V>`	`then(groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)` Schedule closure to be executed after data became available.
`Promise<V>`	`then(Pool pool, groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)` Schedule closure to be executed after data becomes available.
`Promise<V>`	`then(PGroup group, groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)` Schedule closure to be executed after data becomes available.
`void`	`touch()`

Inherited Methods Summary

Inherited Methods
Methods inherited from class	Name
`class DataflowVariable`	`bindDFV, get, get, getError, getRemoteClass, isError, leftShift, leftShift, shouldThrowTimeout, then, then, then, touch`
`class DataflowExpression`	DataflowExpression, binaryChoice, binaryChoice, binaryChoice, binaryChoice, binaryChoice, binaryChoice, bind, bindError, bindSafely, bindUnique, chainWith, chainWith, chainWith, chainWith, chainWith, chainWith, choice, choice, choice, choice, choice, choice, createEventManager, doBind, doBindImpl, doBindRemote, doThenForkAndJoin, evaluate, filter, filter, filter, filter, filter, filter, fireBindError, fireBindError, fireOnMessage, getBindErrorManager, getEventManager, getMetaClass, getProperty, getVal, getVal, getValAsync, getValAsync, handleInterruption, into, into, into, into, into, into, invokeMethod, isBound, join, join, length, merge, merge, merge, merge, merge, merge, merge, merge, merge, merge, merge, merge, notifyRemote, or, or, poll, rightShift, scheduleCallback, separate, separate, separate, separate, separate, separate, setMetaClass, setProperty, split, split, split, split, split, split, split, split, split, split, split, split, subscribe, subscribe, tap, tap, tap, tap, tap, tap, then, then, then, thenForkAndJoin, thenForkAndJoin, thenForkAndJoin, toString, transform, whenBound, whenBound, whenBound, whenBound, wheneverBound, wheneverBound
`class WithSerialId`	`createRemoteHandle, getOrCreateSerialHandle, getRemoteClass, writeReplace`
`class java.lang.Object`	`java.lang.Object#wait(), java.lang.Object#wait(long, int), java.lang.Object#wait(long), java.lang.Object#equals(java.lang.Object), java.lang.Object#toString(), java.lang.Object#hashCode(), java.lang.Object#getClass(), java.lang.Object#notify(), java.lang.Object#notifyAll()`

- Field Detail
  - private final PGroup group
  - private final java.util.concurrent.atomic.AtomicBoolean initializationStarted
  - private final groovy.lang.Closure<T> initializer
- Constructor Detail
  - public LazyDataflowVariable(groovy.lang.Closure<T> initializer)
    
    Creates a new unbound Lazy Dataflow Variable
  - public LazyDataflowVariable(PGroup group, groovy.lang.Closure<T> initializer)
    
    Creates a new unbound Lazy Dataflow Variable with specific a PGroup to use for running the initializer
- Method Detail
  - @java.lang.Override public final java.lang.Throwable getError()
    
    Returns the error bound to the promise
    throws:
    IllegalStateException If not bound or not bound to an error
    
    Returns:
    The error
  - @java.lang.Override public T getVal()
  - @java.lang.Override public T getVal(long timeout, java.util.concurrent.TimeUnit units)
  - @java.lang.Override public void getValAsync(MessageStream callback)
  - @java.lang.Override public void getValAsync(java.lang.Object attachment, MessageStream callback)
  - private void initialize()
  - @java.lang.Override public final boolean isError()
    
    Checks if the promise is bound to an error
    Returns:
    True, if an error has been bound
  - @java.lang.Override public final Promise<V> then(groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)
    
    Schedule closure to be executed after data became available. It is important to notice that even if the expression is already bound the execution of closure will not happen immediately but will be scheduled
    Returns:
    A promise for the results of the supplied closure. This allows for chaining of then() method calls.
    Parameters:
    closure - closure to execute when data becomes available. The closure should take at most one argument.
    errorHandler - closure to execute when an error (instance of Throwable) gets bound. The closure should take at most one argument.
  - @java.lang.Override public final Promise<V> then(Pool pool, groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)
    
    Schedule closure to be executed after data becomes available. It is important to notice that even if the expression is already bound the execution of closure will not happen immediately but will be scheduled.
    Returns:
    A promise for the results of the supplied closure. This allows for chaining of then() method calls.
    Parameters:
    pool - The thread pool to use for task scheduling for asynchronous message delivery
    closure - closure to execute when data becomes available. The closure should take at most one argument.
    errorHandler - closure to execute when an error (instance of Throwable) gets bound. The closure should take at most one argument.
  - @java.lang.Override public final Promise<V> then(PGroup group, groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)
    
    Schedule closure to be executed after data becomes available. It is important to notice that even if the expression is already bound the execution of closure will not happen immediately but will be scheduled.
    Returns:
    A promise for the results of the supplied closure. This allows for chaining of then() method calls.
    Parameters:
    group - The PGroup to use for task scheduling for asynchronous message delivery
    closure - closure to execute when data becomes available. The closure should take at most one argument.
    errorHandler - closure to execute when an error (instance of Throwable) gets bound. The closure should take at most one argument.
  - @java.lang.Override public void touch()

Summary:
Field
Constructor
Method

| Detail:
Field
Constructor
Method

[Java] Class LazyDataflowVariable<T>

Field Summary

Constructor Summary

Methods Summary

Inherited Methods Summary

Field Detail

private final PGroup group

private final java.util.concurrent.atomic.AtomicBoolean initializationStarted

private final groovy.lang.Closure<T> initializer

Constructor Detail

public LazyDataflowVariable(groovy.lang.Closure<T> initializer)

public LazyDataflowVariable(PGroup group, groovy.lang.Closure<T> initializer)

Method Detail

@java.lang.Override public final java.lang.Throwable getError()

@java.lang.Override public T getVal()

@java.lang.Override public T getVal(long timeout, java.util.concurrent.TimeUnit units)

@java.lang.Override public void getValAsync(MessageStream callback)

@java.lang.Override public void getValAsync(java.lang.Object attachment, MessageStream callback)

private void initialize()

@java.lang.Override public final boolean isError()

@java.lang.Override public final Promise<V> then(groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)

@java.lang.Override public final Promise<V> then(Pool pool, groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)

@java.lang.Override public final Promise<V> then(PGroup group, groovy.lang.Closure<V> closure, groovy.lang.Closure<V> errorHandler)

@java.lang.Override public void touch()