com.tinkerpop.pipes.branch

Class LoopPipe<S>

java.lang.Object

com.tinkerpop.pipes.AbstractPipe<S,E>

com.tinkerpop.pipes.util.AbstractMetaPipe<S,S>

com.tinkerpop.pipes.branch.LoopPipe<S>

All Implemented Interfaces:

Pipe<S,S>, MetaPipe, Iterable<S>, Iterator<S>

public class LoopPipe<S>
extends AbstractMetaPipe<S,S>
implements MetaPipe

LoopPipe takes one or two Boolean-based PipeFunctions. For each object of the LoopPipe, the "while" PipeFunction is called. The input of the while PipeFunction is a LoopBundle object which is the object plus some metadata. The boolean of the while PipeFunction determines whether the object should be put back at the start of the LoopPipe or not. The "emit" PipeFunction determines whether the current object should be emitted or not.

Author:

Marko A. Rodriguez (http://markorodriguez.com)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LoopPipe.LoopBundle<T>

Field Summary

Fields inherited from class com.tinkerpop.pipes.AbstractPipe

currentEnd, pathEnabled, starts

Fields inherited from interface com.tinkerpop.pipes.Pipe

NO_PATH_MESSAGE

Constructor Summary

Constructors

Constructor and Description
LoopPipe(Pipe<S,S> pipe, PipeFunction<LoopPipe.LoopBundle<S>,Boolean> whileFunction)
LoopPipe(Pipe<S,S> pipe, PipeFunction<LoopPipe.LoopBundle<S>,Boolean> whileFunction, PipeFunction<LoopPipe.LoopBundle<S>,Boolean> emitFunction)

Method Summary

Methods

Modifier and Type	Method and Description
static PipeFunction<LoopPipe.LoopBundle,Boolean>	createLoopsFunction(int loops)
static PipeFunction<Object,Boolean>	createTrueFunction()
List	getCurrentPath() Returns the transformation path to arrive at the current object of the pipe.
int	getLoops()
List<Pipe>	getPipes()
protected S	processNextStart()
void	reset() A pipe may maintain state.
void	setStarts(Iterator<S> iterator) Set an iterator of S objects to the head (start) of the pipe.
String	toString()

Methods inherited from class com.tinkerpop.pipes.util.AbstractMetaPipe

enablePath

Methods inherited from class com.tinkerpop.pipes.AbstractPipe

getPathToHere, hasNext, iterator, next, remove, setStarts, setStarts

Methods inherited from class java.lang.Object

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

Constructor Detail

LoopPipe

public LoopPipe(Pipe<S,S> pipe,
        PipeFunction<LoopPipe.LoopBundle<S>,Boolean> whileFunction,
        PipeFunction<LoopPipe.LoopBundle<S>,Boolean> emitFunction)

LoopPipe

public LoopPipe(Pipe<S,S> pipe,
        PipeFunction<LoopPipe.LoopBundle<S>,Boolean> whileFunction)

Method Detail

processNextStart

protected S processNextStart()

Specified by:

processNextStart in class AbstractPipe<S,S>

getPipes

public List<Pipe> getPipes()

Specified by:

getPipes in interface MetaPipe

setStarts

public void setStarts(Iterator<S> iterator)

Description copied from interface: Pipe

Set an iterator of S objects to the head (start) of the pipe.

Specified by:

setStarts in interface Pipe<S,S>

Overrides:

setStarts in class AbstractPipe<S,S>

Parameters:

iterator - the iterator of incoming objects

toString

public String toString()

Overrides:

toString in class AbstractPipe<S,S>

getLoops

public int getLoops()

getCurrentPath

public List getCurrentPath()

Description copied from interface: Pipe

Returns the transformation path to arrive at the current object of the pipe.

Specified by:

getCurrentPath in interface Pipe<S,S>

Overrides:

getCurrentPath in class AbstractPipe<S,S>

Returns:

a List of all of the objects traversed for the current iterator position of the pipe.

reset

public void reset()

Description copied from interface: Pipe

A pipe may maintain state. Reset is used to remove state. The general use case for reset() is to reuse a pipe in another computation without having to create a new Pipe object. An implementation of this method should be recursive whereby the starts (if a Pipe) should have this method called on it.

Specified by:

reset in interface Pipe<S,S>

Overrides:

reset in class AbstractMetaPipe<S,S>

createTrueFunction

public static PipeFunction<Object,Boolean> createTrueFunction()

createLoopsFunction

public static PipeFunction<LoopPipe.LoopBundle,Boolean> createLoopsFunction(int loops)