org.openrdf.query.algebra.evaluation.iterator

Class BottomUpJoinIterator

java.lang.Object

info.aduna.iteration.CloseableIterationBase<E,X>

info.aduna.iteration.LookAheadIteration<BindingSet,QueryEvaluationException>

org.openrdf.query.algebra.evaluation.iterator.BottomUpJoinIterator

All Implemented Interfaces:

CloseableIteration<BindingSet,QueryEvaluationException>, Iteration<BindingSet,QueryEvaluationException>

Direct Known Subclasses:

LimitedSizeBottomUpJoinIterator

public class BottomUpJoinIterator
extends LookAheadIteration<BindingSet,QueryEvaluationException>

Join Iterator that executes a basic bottom-up hash-join algorithm. To be used in cases where interleaved iteration joining is not appropriate (e.g. when the join arguments are subselects).

Author:

jeen

Constructor Summary

Constructors

Constructor and Description
BottomUpJoinIterator(EvaluationStrategy strategy, Join join, BindingSet bindings)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	add(List<BindingSet> leftArgResults, BindingSet b)
protected void	addAll(List<BindingSet> hashTableValues, List<BindingSet> values)
protected long	clearHashTable()
protected BindingSet	getNextElement()
protected void	handleClose()
protected List<BindingSet>	makeList() Utility methods to make it easier to inserted custom store dependent list
protected List<BindingSet>	makeList(List<BindingSet> key) Utility methods to make it easier to inserted custom store dependent list
protected Map<BindingSet,List<BindingSet>>	makeMap() Utility methods to make it easier to inserted custom store dependent maps
protected void	put(Map<BindingSet,List<BindingSet>> hashTable, BindingSet hashKey, List<BindingSet> hashValue)
protected BindingSet	removeFirstElement(List<BindingSet> list) Remove the first (0 index) element from a BindingSet list.

Methods inherited from class info.aduna.iteration.LookAheadIteration

hasNext, next, remove

Methods inherited from class info.aduna.iteration.CloseableIterationBase

close, isClosed

Methods inherited from class java.lang.Object

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

Constructor Detail

BottomUpJoinIterator

public BottomUpJoinIterator(EvaluationStrategy strategy,
                    Join join,
                    BindingSet bindings)
                     throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Detail

getNextElement

protected BindingSet getNextElement()
                             throws QueryEvaluationException

Specified by:

getNextElement in class LookAheadIteration<BindingSet,QueryEvaluationException>

Throws:

QueryEvaluationException

handleClose

protected void handleClose()
                    throws QueryEvaluationException

Overrides:

handleClose in class LookAheadIteration<BindingSet,QueryEvaluationException>

Throws:

QueryEvaluationException

clearHashTable

protected long clearHashTable()

Returns:

the size that the hashtable had before clearing it.

put

protected void put(Map<BindingSet,List<BindingSet>> hashTable,
       BindingSet hashKey,
       List<BindingSet> hashValue)
            throws QueryEvaluationException

Throws:

QueryEvaluationException

addAll

protected void addAll(List<BindingSet> hashTableValues,
          List<BindingSet> values)
               throws QueryEvaluationException

Throws:

QueryEvaluationException

add

protected void add(List<BindingSet> leftArgResults,
       BindingSet b)
            throws QueryEvaluationException

Throws:

QueryEvaluationException

makeMap

protected Map<BindingSet,List<BindingSet>> makeMap()

Utility methods to make it easier to inserted custom store dependent maps

Returns:

map

makeList

protected List<BindingSet> makeList()

Utility methods to make it easier to inserted custom store dependent list

Returns:

list

makeList

protected List<BindingSet> makeList(List<BindingSet> key)

Utility methods to make it easier to inserted custom store dependent list

Returns:

list

removeFirstElement

protected BindingSet removeFirstElement(List<BindingSet> list)
                                 throws QueryEvaluationException

Remove the first (0 index) element from a BindingSet list.

Parameters:

list - which is worked on.

Returns:

the removed BindingSet

Throws:

QueryEvaluationException