Module org.apache.jena.arq

Package org.apache.jena.sparql.engine.join

Class BitSetMapper

java.lang.Object

org.apache.jena.sparql.engine.join.BitSetMapper

public class BitSetMapper
extends Object

Methods for converting collections to and from a bit set representation w.r.t. a list of reference items.

For example, if the list of reference items is [ ?x ?y ?z ] and the given items is the set { ?y ?z } then the resulting bit set has the value 011.

Constructor Summary

Constructors

Constructor	Description
BitSetMapper()

Method Summary

Modifier and Type	Method	Description
static BitSet	toBitSet(List<Var> referenceList, Binding binding)	Create a bit set from the binding's key set.
static <T> List<T>	toList(List<T> referenceList, BitSet key)	Map the positions of all set bits to items in the list.

Methods inherited from class java.lang.Object

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

Constructor Details

BitSetMapper

public BitSetMapper()

Method Details

toBitSet

public static BitSet toBitSet(List<Var> referenceList,
 Binding binding)

Create a bit set from the binding's key set.

Implementation Note:

This method relies on List.indexOf(Object). The class ImmutableUniqueList provides an index for these lookups.

toList

public static <T> List<T> toList(List<T> referenceList,
 BitSet key)

Map the positions of all set bits to items in the list.