Package org.pipecraft.pipes.sync.inter

Class CompoundPipe<T>

java.lang.Object

org.pipecraft.pipes.sync.inter.CompoundPipe<T>

All Implemented Interfaces:

Closeable, AutoCloseable, BasePipe, Pipe<T>

Direct Known Subclasses:

GrouperPipe, HashJoinPipe, HashReductorPipe, MultiFileReaderPipe, MultiTxtFileReaderPipe, StorageMultiFileReaderPipe, StorageMultiTxtFileReaderPipe, StorageTxtFileFetcherReaderPipe

public abstract class CompoundPipe<T>
extends Object
implements Pipe<T>

A pipe encapsulating a pipeline. Subclasses should implement createPipeline() method.

Author:

Eyal Schneider

Constructor Summary

Constructors

Constructor	Description
CompoundPipe()

Method Summary

Modifier and Type	Method	Description
void	close()
protected abstract Pipe<T>	createPipeline()
float	getProgress()
T	next()
T	peek()
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

CompoundPipe

public CompoundPipe()

Method Detail

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Throws:

IOException

next

public T next()
       throws PipeException,
              InterruptedException

Specified by:

next in interface Pipe<T>

Returns:

The next item in this pipe output, or null if the output end has been reached. May be a blocking operation.

Throws:

PipeException - In case of pipe errors in this pipe or somewhere up-stream while trying to prepare next item to return.

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

peek

public T peek()
       throws PipeException

Specified by:

peek in interface Pipe<T>

Returns:

The next item in the pipe's output. Does not remove it, so next call to next() will return it.

Throws:

PipeException - In case of pipe errors in this pipe or somewhere up-stream while trying to prepare next item to return.

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.

Specified by:

start in interface BasePipe

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.

createPipeline

protected abstract Pipe<T> createPipeline()
                                   throws PipeException,
                                          InterruptedException

Returns:

A new pipeline to represent the logic of this pipe

Throws:

PipeException - In case of a pipeline creation error

InterruptedException - In case that the thread is interrupted

getProgress

public float getProgress()

Specified by:

getProgress in interface BasePipe

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.