groovyx.gpars.dataflow.stream

Class DataflowStream<T>

java.lang.Object

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

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

Type Parameters:

T - Type for values to pass through the stream

All Implemented Interfaces:

FList<T>, java.lang.Iterable<T>

public final class DataflowStream<T>
extends StreamCore<T>

Represents a deterministic dataflow channel. Unlike a DataflowQueue, DataflowStream allows multiple readers each to read all the messages. Essentially, you may think of DataflowStream as a 1 to many communication channel, since when a reader consumes a messages, other readers will still be able to read the message. Also, all messages arrive to all readers in the same order. DataflowStream is implemented as a functional queue, which impacts the API in that users have to traverse the values in the stream themselves. On the other hand in offers handy methods for value filtering or transformation together with interesting performance characteristics. For convenience and for the ability to use DataflowStream with other dataflow constructs, like e.g. operators, you can wrap DataflowStreams with DataflowReadAdapter for read access or DataflowWriteAdapter for write access.

The DataflowStream class is designed for single-threaded producers and consumers. If multiple threads are supposed to read or write values to the stream, their access to the stream must be serialized externally or the adapters should be used.

Author:

Johannes Link, Vaclav Pech

Field Summary

Fields inherited from class groovyx.gpars.dataflow.stream.StreamCore

first, rest, wheneverBoundListeners

Constructor Summary

Constructors

Modifier	Constructor and Description
	DataflowStream() Creates an empty stream
	DataflowStream(groovy.lang.Closure toBeApplied) Creates a stream while applying the supplied initialization closure to it
private	DataflowStream(java.util.Collection<MessageStream> wheneverBoundListeners, java.util.Collection<DataflowChannelListener<T>> updateListeners)

Method Summary

Methods

Modifier and Type	Method and Description
protected StreamCore<T>	createNewStream() A factory method to create new instances of the correct class when needed
FList<T>	getRest() Retrieves a DataflowStream representing the rest of this Stream after removing the first element
java.lang.String	toString()

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

addUpdateListener, appendingString, apply, decrementParties, eos, equals, filter, generate, getFirst, getFirstDFV, hashCode, incrementParties, isEmpty, iterator, leftShift, leftShift, map, reduce, reduce, wheneverBound, wheneverBound

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

DataflowStream

public DataflowStream()

Creates an empty stream

DataflowStream

public DataflowStream(groovy.lang.Closure toBeApplied)

Creates a stream while applying the supplied initialization closure to it

Parameters:

toBeApplied - The closure to use for initialization

DataflowStream

private DataflowStream(java.util.Collection<MessageStream> wheneverBoundListeners,
              java.util.Collection<DataflowChannelListener<T>> updateListeners)

Method Detail

getRest

public FList<T> getRest()

Retrieves a DataflowStream representing the rest of this Stream after removing the first element

Specified by:

getRest in interface FList<T>

Specified by:

getRest in class StreamCore<T>

Returns:

The remaining stream elements

createNewStream

protected StreamCore<T> createNewStream()

A factory method to create new instances of the correct class when needed

Specified by:

createNewStream in class StreamCore<T>

Returns:

An instance of the appropriate sub-class

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object