com.tinkerpop.pipes.util

Class PipeHelper

java.lang.Object

com.tinkerpop.pipes.util.PipeHelper

public class PipeHelper
extends Object

PipeHelper provides a collection of static methods that are useful when dealing with Pipes.

Author:

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

Method Summary

Methods

Modifier and Type	Method and Description
static boolean	areEqual(Iterator ittyA, Iterator ittyB) Checks if the contents of the two iterators are equal and of the same length.
static long	counter(Iterator iterator) Count the number of objects in an iterator.
static PipeFunction	createPipeFunction(Class clazz, String methodName, Class... argumentTypes) Create a PipeFunction for a static method.
static PipeFunction	createPipeFunction(Method method) Create a PipeFunction for a static method.
static <T> Iterator<T>	emptyIterator()
static <T> void	fillCollection(Iterator<T> iterator, Collection<T> collection) Drain an iterator into a collection.
static <T> void	fillCollection(Iterator<T> iterator, Collection<T> collection, int number) Drain an iterator into a collection.
static <T> void	iterate(Iterator<T> iterator) This will iterate all the objects out of the iterator.
static <T> List<T>	makeList(Iterator<T> iterator) Drains the iterator into a list that is returned by the method.
static String	makePipeString(Pipe pipe, Object... arguments) Generate a String representation of a pipe given the pipe and some arguments of the pipe.

Methods inherited from class java.lang.Object

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

Method Detail

iterate

public static <T> void iterate(Iterator<T> iterator)

This will iterate all the objects out of the iterator. This is useful for iterators with side-effect behavior as nothing is returned from the iteration. Note that the try/catch model is not "acceptable Java," but is more efficient given the architecture of AbstractPipe.

Parameters:

iterator - the iterator to drain

fillCollection

public static <T> void fillCollection(Iterator<T> iterator,
                      Collection<T> collection)

Drain an iterator into a collection. Useful for storing the results of a Pipe into a collection. Note that the try/catch model is not "acceptable Java," but is more efficient given the architecture of AbstractPipe.

Type Parameters:

T - the object type of the iterator

Parameters:

iterator - the iterator to drain

collection - the collection to fill

fillCollection

public static <T> void fillCollection(Iterator<T> iterator,
                      Collection<T> collection,
                      int number)

Drain an iterator into a collection. Useful for storing the results of a Pipe into a collection. Note that the try/catch model is not "acceptable Java," but is more efficient given the architecture of AbstractPipe.

Type Parameters:

T - the object type of the iterator

Parameters:

iterator - the iterator to drain

collection - the collection to fill

number - the number of objects to fill into the collection (ordered by iterator)

makeList

public static <T> List<T> makeList(Iterator<T> iterator)

Drains the iterator into a list that is returned by the method.

Type Parameters:

T - the object type of the iterator

Parameters:

iterator - the iterator to drain into the list

Returns:

a list filled with the objects of the iterator

counter

public static long counter(Iterator iterator)

Count the number of objects in an iterator. This will exhaust the iterator. Note that the try/catch model is not "acceptable Java," but is more efficient given the architecture of AbstractPipe.

Parameters:

iterator - the iterator to count

Returns:

the number of objects in the iterator

areEqual

public static boolean areEqual(Iterator ittyA,
               Iterator ittyB)

Checks if the contents of the two iterators are equal and of the same length. Equality is determined using == operator on the internal objects.

Parameters:

ittyA - An iterator

ittyB - An iterator

Returns:

Returns true if the two iterators contain the same objects and are of the same length

makePipeString

public static String makePipeString(Pipe pipe,
                    Object... arguments)

Generate a String representation of a pipe given the pipe and some arguments of the pipe.

Parameters:

pipe - the pipe's class.getSimpleName() is used

arguments - arguments used in the configuration of the pipe (please avoid objects with massive toString() representations)

Returns:

a String representation of the pipe

createPipeFunction

public static PipeFunction createPipeFunction(Method method)

Create a PipeFunction for a static method. The method represents PipeFunction.compute().

Parameters:

method - a single argument, static method that will be invoked for when PipeFunction.compute() is called

Returns:

a PipeFunction based on the provided compute method

createPipeFunction

public static PipeFunction createPipeFunction(Class clazz,
                              String methodName,
                              Class... argumentTypes)

Create a PipeFunction for a static method. The method represents PipeFunction.compute().

Parameters:

clazz - the class hosting the method

methodName - the string representation of the method

argumentTypes - the classes of the arguments

Returns:

a PipeFunction based on the retrieved compute method

emptyIterator

public static <T> Iterator<T> emptyIterator()