Class PermutationIterator<T>

java.lang.Object

net.sf.colossus.util.PermutationIterator<T>

All Implemented Interfaces:

Iterator<List<T>>

public final class PermutationIterator<T>
extends Object
implements Iterator<List<T>>

An iterator that returns permutations of the originally passed list. The first permutation is the unmodified list.

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	anyLeft
private boolean	first
private boolean	foundNext
private int	nextSwap
private final List<T>	permList
private final PermGen	pg

Constructor Summary

Constructors

Constructor	Description
PermutationIterator(List<T> list)	Set up a permutation generator for the passed list.

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()	hasNext should not change things if called repeatedly, so when it's called we'll lazily evaluate the next permutation, and then keep returning true until next() is called.
List<T>	next()
void	remove()
private void	swap(int lower)	Swap elements lower and lower + 1 of permList

Methods inherited from class Object

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

Methods inherited from interface Iterator

forEachRemaining

Field Details

permList

private final List<T> permList

pg

private final PermGen pg

foundNext

private boolean foundNext

anyLeft

private boolean anyLeft

first

private boolean first

nextSwap

private int nextSwap

Constructor Details

PermutationIterator

public PermutationIterator(List<T> list)

Set up a permutation generator for the passed list.

Method Details

hasNext

public boolean hasNext()

hasNext should not change things if called repeatedly, so when it's called we'll lazily evaluate the next permutation, and then keep returning true until next() is called.

Specified by:

hasNext in interface Iterator<T>

next

public List<T> next()

Specified by:

next in interface Iterator<T>

remove

public void remove()

Specified by:

remove in interface Iterator<T>

swap

private void swap(int lower)

Swap elements lower and lower + 1 of permList