com.rubecula.util
Class RandomIterable<E>

java.lang.Object
  com.rubecula.util.RandomIterable<E>

Type Parameters:

E - the Generic type for this Iterator TODO consider extending AToString

All Implemented Interfaces:

java.lang.Iterable<E>

Direct Known Subclasses:

Lek

public class RandomIterable<E>
extends java.lang.Object
implements java.lang.Iterable<E>

Decorate a Collection as an Iterator such that the order of visiting the elements in the collection is random. IMPORTANT NOTE: a RandomIterable is not backed by the underlying collection. That is to say, if the collection changes, the iterator will not be aware of the change. Removing an element from this iterator does NOT remove the element from the underlying collection. TODO consider trying to implement it such that it really is backed by the underlying collection.

Author:

Robin Hillyard

Field Summary

protected java.util.List<E>	_list A complete copy of the collection passed in, but in a random order.
protected int	_size

Constructor Summary

RandomIterable(java.util.Collection<E> collection, org.apache.commons.math.random.RandomGenerator random)

RandomIterable(java.util.Collection<E> collection, org.apache.commons.math.random.RandomGenerator random, int sampleSize)

Method Summary

java.lang.Iterable<E>	getRemainder()
boolean	isSample()
java.util.Iterator<E>	iterator()
void	reset() Re-examine the underlying collection and rebuild the _list based on new values from the random number source, i.e.
int	size()

Methods inherited from class java.lang.Object

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

Field Detail

_list

protected java.util.List<E> _list

A complete copy of the collection passed in, but in a random order.

_size

protected int _size

Constructor Detail

RandomIterable

public RandomIterable(java.util.Collection<E> collection,
                      org.apache.commons.math.random.RandomGenerator random)

Parameters:

collection - the collection we want to iterate randomly through.

random - the random number generator to be used (useful if we want to seed the random number generator).

RandomIterable

public RandomIterable(java.util.Collection<E> collection,
                      org.apache.commons.math.random.RandomGenerator random,
                      int sampleSize)

Parameters:

collection - the collection we want to iterate through.

random - the random number generator to be used (useful if we want to seed the random number generator).

sampleSize - the maximum number of elements to put in the iterator.

Method Detail

getRemainder

public java.lang.Iterable<E> getRemainder()

Returns:

the remainder of the collection, ie. those not contained in this iterator.

isSample

public boolean isSample()

Returns:

true if this iterator represents only a sample of the complete collection passed in to the constructor.

iterator

public java.util.Iterator<E> iterator()

Specified by:

iterator in interface java.lang.Iterable<E>

See Also:

Iterable.iterator()

reset

public void reset()

Re-examine the underlying collection and rebuild the _list based on new values from the random number source, i.e. the list will be in a new order. If the underlying collection has changed, it may be that the result of calling isSample() will be different from previously.

size

public int size()

Returns:

the size