org.apache.tinkerpop.gremlin.algorithm.generator

Class SizableIterable<T>

java.lang.Object

org.apache.tinkerpop.gremlin.algorithm.generator.SizableIterable<T>

All Implemented Interfaces:

Iterable<T>

public class SizableIterable<T>
extends Object
implements Iterable<T>

Utility class to make size determinations for Iterable for efficient.

If the number of elements in an Iterable is known, then the Iterable can be wrapped in this class to make determining the size a constant time operation rather than an iteration over the whole Iterable.

Some generators need to know the number of vertices prior to generation. Using this class can speed up the generator.

Author:

Matthias Broecheler (me@matthiasb.com)

Constructor Summary

Constructors

Constructor and Description
SizableIterable(Iterable<T> iterable, int size) Wraps the given Iterable with the given size.

Method Summary

Modifier and Type	Method and Description
Iterator<T>	iterator()
int	size() Returns the size of the Iterable
static <T> int	sizeOf(Iterable<T> iterable) Utility method to determine the number of elements in an Iterable.

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Detail

SizableIterable

public SizableIterable(Iterable<T> iterable,
                       int size)

Wraps the given Iterable with the given size.

NOTE: the size MUST be the size of the Iterable. This is not verified.

Method Detail

size

public int size()

Returns the size of the Iterable

Returns:

Size of the Iterable

iterator

public Iterator<T> iterator()

Specified by:

iterator in interface Iterable<T>

sizeOf

public static <T> int sizeOf(Iterable<T> iterable)

Utility method to determine the number of elements in an Iterable.

Checks if the given Iterable is an instance of a Collection or SizableIterable before iterating to improve performance.

Returns:

The size of the given Iterable.