Package org.pipecraft.pipes.terminal

Class ParallelConsumerPipe

java.lang.Object

org.pipecraft.pipes.terminal.TerminalPipe

org.pipecraft.pipes.terminal.ParallelConsumerPipe

All Implemented Interfaces:

Closeable, AutoCloseable, BasePipe

public class ParallelConsumerPipe
extends TerminalPipe

A terminal pipe that consumes multiple input pipes in a parallel manner, with a configurable number of threads. For thread safety reasons, it is guaranteed that each pipe is consumed by exactly one thread. Each of the input pipes may be of any type: sync, async or terminal.

Author:

Eyal Schneider

Constructor Summary

Constructors

Constructor	Description
ParallelConsumerPipe(int parallelism, Collection<? extends BasePipe> inputs)	Constructor
ParallelConsumerPipe(int parallelism, Collection<? extends BasePipe> inputs, Runnable terminationAction)	Constructor
ParallelConsumerPipe(int parallelism, BasePipe... inputs)	Constructor

Method Summary

Modifier and Type	Method	Description
void	close()
float	getProgress()
void	start()	Performs pre-processing prior to item flow throw the pipe.

Methods inherited from class java.lang.Object

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

Constructor Detail

ParallelConsumerPipe

public ParallelConsumerPipe(int parallelism,
                            Collection<? extends BasePipe> inputs,
                            Runnable terminationAction)

Constructor

Parameters:

parallelism - The number of threads to use for consuming all pipes

inputs - The input pipes

terminationAction - An action to perform once all input items from all pipes have been consumed. Runs once, upon a successful iteration termination only. Must be thread safe!

ParallelConsumerPipe

public ParallelConsumerPipe(int parallelism,
                            Collection<? extends BasePipe> inputs)

Constructor

Parameters:

parallelism - The number of threads to use for consuming all pipes

inputs - The input pipes

ParallelConsumerPipe

public ParallelConsumerPipe(int parallelism,
                            BasePipe... inputs)

Constructor

Parameters:

parallelism - The number of threads to use for consuming all pipes

inputs - The input pipes

Method Detail

close

public void close()
           throws IOException

Throws:

IOException

start

public void start()
           throws PipeException,
                  InterruptedException

Description copied from interface: BasePipe

Performs pre-processing prior to item flow throw the pipe. Implementations must call the same method for all their input pipes before accessing their items. This is typically done here.

Throws:

PipeException - In case of pipe errors in this pipe or somewhere up-stream.

InterruptedException - In case that the operation has been interrupted by another thread.

getProgress

public float getProgress()

Specified by:

getProgress in interface BasePipe

Overrides:

getProgress in class TerminalPipe

Returns:

The pipe flow progress, as a floating number between 0.0 and 1.0. Important implementation rules: 1) Calling this method before start() call is complete isn't allowed and has an undefined behavior. 2) Implementation should do best effort to provide an estimate of the progress this pipe has made (0.0 - 1.0) 3) When the pipe is fully consumed, getProgress() should return 1.0. 4) Results must be monotonous, i.e. results of consecutive calls may never be decreasing. 5) Thread safety: progress may be maintained by some thread/s but monitoring by other threads. Implementations must be thread safe.