Package org.plumelib.util

Class CombinationIterator<T>

java.lang.Object

org.plumelib.util.CombinationIterator<T>

Type Parameters:

T - the type of the elements of the collections

All Implemented Interfaces:

Iterator<List<T>>

public class CombinationIterator<T>
extends Object
implements Iterator<List<T>>

Given a set of collections, yield each combination that takes one element from each collection. Each tuple has a value from each candidate list. Each combination'slength is the same as the number of input lists.

For instance, given [["a1", "a2"], ["b1"], ["c1", "c2", "c3"]], this class yields in turn:

   ["a1", "b1", "c1"]
   ["a1", "b1", "c2"]
   ["a1", "b1", "c3"]
   ["a2", "b1", "c1"]
   ["a2", "b1", "c2"]
   ["a2", "b1", "c3"]
 

Constructor Summary

Constructors

Constructor	Description
CombinationIterator(Collection<? extends Collection<T>> collectionsOfCandidates)	Creates a CombinationIterator for lists constructed from the given candidates.

Method Summary

Modifier and Type	Method	Description
boolean	hasNext()
List<T>	next()
void	remove()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Iterator

forEachRemaining

Constructor Details

CombinationIterator

public CombinationIterator(Collection<? extends Collection<T>> collectionsOfCandidates)

Creates a CombinationIterator for lists constructed from the given candidates. Each generated list will be the same length as the given list.

Parameters:

collectionsOfCandidates - lists of candidate values for each position in generated lists

Method Details

hasNext

@EnsuresNonNullIf(expression="nextValue",
                  result=true)
public boolean hasNext(@GuardSatisfied CombinationIterator<T> this)

Specified by:

hasNext in interface Iterator<T>

next

public List<T> next(@GuardSatisfied CombinationIterator<T> this)

Specified by:

next in interface Iterator<T>

remove

public void remove(@GuardSatisfied CombinationIterator<T> this)

Specified by:

remove in interface Iterator<T>