net.sf.tweety.commons.util

Class DefaultSubsetIterator<T>

java.lang.Object

net.sf.tweety.commons.util.SubsetIterator<T>

net.sf.tweety.commons.util.DefaultSubsetIterator<T>

Type Parameters:

T - The element class which is iterated.

All Implemented Interfaces:

java.util.Iterator<java.util.Set<T>>

public class DefaultSubsetIterator<T>
extends SubsetIterator<T>

Iterates over all subsets of a given sets. The order is given by the increment of a bitset as follows. Let {1,2,3,4} a set where a subsets should be enumerated. Then a bitset 0000 of the same length is initialized. At every next() operation the bitset is incremented in the standard way (0000->0001,... 0101->0110,...) and the set is returned which contains exactly the elements at the indices with 1 in the bitset.

Author:

Matthias Thimm

Field Summary

Fields

Modifier and Type	Field and Description
private java.util.BitSet	currentItem The number of the current item as a bit set.
private java.util.List<T>	set The set over which subsets are iterated.

Constructor Summary

Constructors

Constructor and Description
DefaultSubsetIterator(java.util.Set<T> set) Creates a new subset iterator for the given set.

Method Summary

Modifier and Type	Method and Description
boolean	hasNext()
private java.util.BitSet	increment(java.util.BitSet bitSet) Increments the given bit set, returns null if an overflow happens.
java.util.Set<T>	next()

Methods inherited from class net.sf.tweety.commons.util.SubsetIterator

getSet, 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

Field Detail

set

private java.util.List<T> set

The set over which subsets are iterated.

currentItem

private java.util.BitSet currentItem

The number of the current item as a bit set.

Constructor Detail

DefaultSubsetIterator

public DefaultSubsetIterator(java.util.Set<T> set)

Creates a new subset iterator for the given set.

Parameters:

set - some set.

Method Detail

hasNext

public boolean hasNext()

Specified by:

hasNext in interface java.util.Iterator<java.util.Set<T>>

Specified by:

hasNext in class SubsetIterator<T>

next

public java.util.Set<T> next()

Specified by:

next in interface java.util.Iterator<java.util.Set<T>>

Specified by:

next in class SubsetIterator<T>

increment

private java.util.BitSet increment(java.util.BitSet bitSet)

Increments the given bit set, returns null if an overflow happens.

Parameters:

bitSet - some bit set.

Returns:

the incremented bit set