groovyx.gpars.dataflow

Class SyncDataflowStreamReadAdapter<T>

java.lang.Object

groovyx.gpars.dataflow.stream.DataflowStreamReadAdapter<T>

groovyx.gpars.dataflow.SyncDataflowStreamReadAdapter<T>

Type Parameters:

T - The type of messages to pass through the stream

All Implemented Interfaces:

DataflowReadChannel<T>, SelectableChannel<T>

final class SyncDataflowStreamReadAdapter<T>
extends DataflowStreamReadAdapter<T>

Provides a special implementation of DataflowStreamReadAdapter, which cooperates with SyncDataflowBroadcast subscription and un-subscription mechanism.

Author:

Vaclav Pech

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	closed
private boolean	wheneverBoundSet

Constructor Summary

Constructors

Constructor and Description
SyncDataflowStreamReadAdapter(StreamCore<T> stream) Creates a new adapter

Method Summary

Methods

Modifier and Type	Method and Description
<V> DataflowReadChannel<V>	chainWith(PGroup group, groovy.lang.Closure<V> closure) Creates and attaches a new operator processing values from the channel
private void	checkClosed()
(package private) void	close() Closes the channel so that it cannot be used any longer
T	getVal() Reads the current value of the channel.
T	getVal(long timeout, java.util.concurrent.TimeUnit units) Reads the current value of the channel.
void	getValAsync(MessageStream callback) Asynchronously retrieves the value from the channel.
void	getValAsync(java.lang.Object attachment, MessageStream callback) Asynchronously retrieves the value from the channel.
boolean	isBound() Check if value has been set already for this expression
java.util.Iterator<T>	iterator()
<V> DataflowReadChannel<V>	merge(PGroup group, java.util.List<DataflowReadChannel<java.lang.Object>> others, groovy.lang.Closure<V> closure) Merges channels together as inputs for a single dataflow operator.
DataflowExpression<T>	poll() Retrieves the value at the head of the buffer.
<V> Promise<V>	rightShift(groovy.lang.Closure<V> closure) Schedule closure to be executed after data became available.
DataflowReadChannel<T>	tap(PGroup group, DataflowWriteChannel<T> target) Taps into the pipeline.
<V> void	whenBound(groovy.lang.Closure<V> closure) Schedule closure to be executed after data becomes available.
void	whenBound(MessageStream stream) Send the bound data to provided stream when it becomes available
<V> void	whenBound(PGroup group, groovy.lang.Closure<V> closure) Schedule closure to be executed after data becomes available.
<V> void	whenBound(Pool pool, groovy.lang.Closure<V> closure) Schedule closure to be executed by pooled actor after data becomes available.
<V> void	wheneverBound(groovy.lang.Closure<V> closure) Send all pieces of data bound in the future to the provided stream when it becomes available.
void	wheneverBound(MessageStream stream) Send all pieces of data bound in the future to the provided stream when it becomes available.

Methods inherited from class groovyx.gpars.dataflow.stream.DataflowStreamReadAdapter

allUnprocessedDFVs, binaryChoice, binaryChoice, binaryChoice, binaryChoice, binaryChoice, binaryChoice, chainWith, chainWith, chainWith, chainWith, chainWith, choice, choice, choice, choice, choice, choice, filter, filter, filter, filter, filter, filter, getEventManager, into, into, into, into, into, into, length, merge, merge, merge, merge, merge, merge, merge, merge, merge, merge, merge, or, or, separate, separate, separate, separate, separate, separate, split, split, split, split, split, split, split, split, split, split, split, split, tap, tap, tap, tap, tap, then, then, then, toString

Methods inherited from class java.lang.Object

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

Field Detail

closed

private boolean closed

wheneverBoundSet

private boolean wheneverBoundSet

Constructor Detail

SyncDataflowStreamReadAdapter

SyncDataflowStreamReadAdapter(StreamCore<T> stream)

Creates a new adapter

Parameters:

stream - The stream to wrap

Method Detail

iterator

public java.util.Iterator<T> iterator()

Overrides:

iterator in class DataflowStreamReadAdapter<T>

getVal

public T getVal()
         throws java.lang.InterruptedException

Description copied from interface: DataflowReadChannel

Reads the current value of the channel. Blocks, if the value has not been assigned yet.

Specified by:

getVal in interface DataflowReadChannel<T>

Overrides:

getVal in class DataflowStreamReadAdapter<T>

Returns:

The actual value

Throws:

java.lang.InterruptedException - If the current thread gets interrupted while waiting for the channel to be bound

getVal

public T getVal(long timeout,
       java.util.concurrent.TimeUnit units)
         throws java.lang.InterruptedException

Description copied from interface: DataflowReadChannel

Reads the current value of the channel. Blocks up to given timeout, if the value has not been assigned yet.

Specified by:

getVal in interface DataflowReadChannel<T>

Overrides:

getVal in class DataflowStreamReadAdapter<T>

Parameters:

timeout - The timeout value

units - Units for the timeout

Returns:

The actual value

Throws:

java.lang.InterruptedException - If the current thread gets interrupted while waiting for the channel to be bound

getValAsync

public void getValAsync(MessageStream callback)

Description copied from interface: DataflowReadChannel

Asynchronously retrieves the value from the channel. Sends the actual value of the channel as a message back the the supplied actor once the value has been bound. The actor can perform other activities or release a thread back to the pool by calling react() waiting for the message with the value of the Dataflow channel.

Specified by:

getValAsync in interface DataflowReadChannel<T>

Overrides:

getValAsync in class DataflowStreamReadAdapter<T>

Parameters:

callback - An actor to send the bound value to.

getValAsync

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

Description copied from interface: DataflowReadChannel

Asynchronously retrieves the value from the channel. Sends a message back the the supplied MessageStream with a map holding the supplied attachment under the 'attachment' key and the actual value of the channel under the 'result' key once the value has been bound. Attachment is an arbitrary value helping the actor.operator match its request with the reply. The actor/operator can perform other activities or release a thread back to the pool by calling react() waiting for the message with the value of the Dataflow channel.

Specified by:

getValAsync in interface DataflowReadChannel<T>

Overrides:

getValAsync in class DataflowStreamReadAdapter<T>

Parameters:

attachment - arbitrary non-null attachment if reader needs better identification of result

callback - An actor to send the bound value plus the supplied index to.

rightShift

public <V> Promise<V> rightShift(groovy.lang.Closure<V> closure)

Description copied from interface: DataflowReadChannel

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

rightShift() redefines the >> operator so you can write df >> {println it} instead of df.whenBound{println it}

Specified by:

rightShift in interface DataflowReadChannel<T>

Overrides:

rightShift in class DataflowStreamReadAdapter<T>

Parameters:

closure - closure to execute when data becomes available. The closure should take at most one argument.

Returns:

A promise for the results of the supplied closure. This allows for chaining of then() method calls.

whenBound

public <V> void whenBound(groovy.lang.Closure<V> closure)

Description copied from interface: DataflowReadChannel

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.

Specified by:

whenBound in interface DataflowReadChannel<T>

Overrides:

whenBound in class DataflowStreamReadAdapter<T>

Parameters:

closure - closure to execute when data becomes available. The closure should take at most one argument.

whenBound

public <V> void whenBound(Pool pool,
                 groovy.lang.Closure<V> closure)

Schedule closure to be executed by pooled actor 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.

Specified by:

whenBound in interface DataflowReadChannel<T>

Overrides:

whenBound in class DataflowStreamReadAdapter<T>

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.

whenBound

public <V> void whenBound(PGroup group,
                 groovy.lang.Closure<V> closure)

Description copied from interface: DataflowReadChannel

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.

Specified by:

whenBound in interface DataflowReadChannel<T>

Overrides:

whenBound in class DataflowStreamReadAdapter<T>

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.

whenBound

public void whenBound(MessageStream stream)

Description copied from interface: DataflowReadChannel

Send the bound data to provided stream when it becomes available

Specified by:

whenBound in interface DataflowReadChannel<T>

Overrides:

whenBound in class DataflowStreamReadAdapter<T>

Parameters:

stream - stream where to send result

wheneverBound

public <V> void wheneverBound(groovy.lang.Closure<V> closure)

Description copied from interface: SelectableChannel

Send all pieces of data bound in the future to the provided stream when it becomes available. *

Specified by:

wheneverBound in interface SelectableChannel<T>

Overrides:

wheneverBound in class DataflowStreamReadAdapter<T>

Parameters:

closure - closure to execute when data becomes available. The closure should take at most one argument.

wheneverBound

public void wheneverBound(MessageStream stream)

Description copied from interface: SelectableChannel

Send all pieces of data bound in the future to the provided stream when it becomes available.

Specified by:

wheneverBound in interface SelectableChannel<T>

Overrides:

wheneverBound in class DataflowStreamReadAdapter<T>

Parameters:

stream - stream where to send result

chainWith

public <V> DataflowReadChannel<V> chainWith(PGroup group,
                                   groovy.lang.Closure<V> closure)

Description copied from interface: DataflowReadChannel

Creates and attaches a new operator processing values from the channel

Specified by:

chainWith in interface DataflowReadChannel<T>

Overrides:

chainWith in class DataflowStreamReadAdapter<T>

Type Parameters:

V - The type of values returned from the supplied closure

Parameters:

group - The PGroup to use

closure - The function to invoke on all incoming values as part of the new operator's body

Returns:

A channel of the same type as this channel, which the new operator will output into.

tap

public DataflowReadChannel<T> tap(PGroup group,
                         DataflowWriteChannel<T> target)

Description copied from interface: DataflowReadChannel

Taps into the pipeline. The supplied channel will receive a copy of all messages passed through.

Specified by:

tap in interface DataflowReadChannel<T>

Overrides:

tap in class DataflowStreamReadAdapter<T>

Parameters:

group - The PGroup to use

target - The channel to tap data into

Returns:

A channel of the same type as this channel, which the new operator will output into.

merge

public <V> DataflowReadChannel<V> merge(PGroup group,
                               java.util.List<DataflowReadChannel<java.lang.Object>> others,
                               groovy.lang.Closure<V> closure)

Description copied from interface: DataflowReadChannel

Merges channels together as inputs for a single dataflow operator.

Specified by:

merge in interface DataflowReadChannel<T>

Overrides:

merge in class DataflowStreamReadAdapter<T>

Type Parameters:

V - The type of values passed between the channels

Parameters:

group - The PGroup to use

others - The channels to merge with

closure - The function to invoke on all incoming values as part of the new operator's body. The number of arguments to the closure must match the number of input channels.

Returns:

A channel of the same type as this channel, which the new operator will output into.

isBound

public boolean isBound()

Description copied from interface: DataflowReadChannel

Check if value has been set already for this expression

Specified by:

isBound in interface DataflowReadChannel<T>

Overrides:

isBound in class DataflowStreamReadAdapter<T>

Returns:

true if bound already

poll

public DataflowExpression<T> poll()
                           throws java.lang.InterruptedException

Description copied from interface: SelectableChannel

Retrieves the value at the head of the buffer. Returns null, if no value is available.

Specified by:

poll in interface SelectableChannel<T>

Overrides:

poll in class DataflowStreamReadAdapter<T>

Returns:

The value bound to the DFV at the head of the stream or null

Throws:

java.lang.InterruptedException - If the current thread is interrupted

checkClosed

private void checkClosed()

close

void close()
     throws java.lang.InterruptedException

Closes the channel so that it cannot be used any longer

Throws:

java.lang.InterruptedException - When the thread gets interrupted