org.openrdf.query.algebra.evaluation.iterator

Class HashJoinIteration

java.lang.Object

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

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

org.openrdf.query.algebra.evaluation.iterator.HashJoinIteration

All Implemented Interfaces:

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

Direct Known Subclasses:

LimitedSizeHashJoinIteration

public class HashJoinIteration
extends LookAheadIteration<BindingSet,QueryEvaluationException>

Generic hash join implementation suitable for use by Sail implementations.

Author:

MJAHale

Constructor Summary

Constructors

Constructor and Description
HashJoinIteration(EvaluationStrategy strategy, Join join, BindingSet bindings)
HashJoinIteration(EvaluationStrategy strategy, Join join, BindingSet bindings, boolean leftJoin)

Method Summary

Modifier and Type	Method and Description
protected <E> void	add(Collection<E> col, E value)
protected <E> void	addAll(Collection<E> col, List<E> values)
protected <E> void	closeHashValue(Iterator<E> iter) Utility methods to clear-up in case not using in-memory hash table
protected void	disposeCache(Iterator<BindingSet> iter) Utility methods to clear-up in case not using in-memory cache
protected void	disposeHashTable(Map<BindingSetHashKey,List<BindingSet>> map) Utility methods to clear-up in case not using in-memory hash table
protected BindingSet	getNextElement() Gets the next element.
protected void	handleClose() Called by CloseableIterationBase.close() when it is called for the first time.
protected Map<BindingSetHashKey,List<BindingSet>>	makeHashTable(int initialSize) Utility methods to make it easier to inserted custom store dependent maps
protected List<BindingSet>	makeHashValue(int currentMaxListSize) Utility methods to make it easier to inserted custom store dependent list
protected Collection<BindingSet>	makeIterationCache(CloseableIteration<BindingSet,QueryEvaluationException> iter) Utility methods to make it easier to inserted custom store dependent list
protected <E> E	nextFromCache(Iterator<E> iter)
protected void	putHashTableEntry(Map<BindingSetHashKey,List<BindingSet>> hashTable, BindingSetHashKey hashKey, List<BindingSet> hashValue)

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

HashJoinIteration

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

Throws:

QueryEvaluationException

HashJoinIteration

public HashJoinIteration(EvaluationStrategy strategy,
                         Join join,
                         BindingSet bindings,
                         boolean leftJoin)
                  throws QueryEvaluationException

Throws:

QueryEvaluationException

Method Detail

getNextElement

protected BindingSet getNextElement()
                             throws QueryEvaluationException

Description copied from class: LookAheadIteration

Gets the next element. Subclasses should implement this method so that it returns the next element.

Specified by:

getNextElement in class LookAheadIteration<BindingSet,QueryEvaluationException>

Returns:

The next element, or null if no more elements are available.

Throws:

QueryEvaluationException

handleClose

protected void handleClose()
                    throws QueryEvaluationException

Description copied from class: CloseableIterationBase

Called by CloseableIterationBase.close() when it is called for the first time. This method is only called once on each iteration. By default, this method does nothing.

Overrides:

handleClose in class LookAheadIteration<BindingSet,QueryEvaluationException>

Throws:

QueryEvaluationException

putHashTableEntry

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

Throws:

QueryEvaluationException

makeIterationCache

protected Collection<BindingSet> makeIterationCache(CloseableIteration<BindingSet,QueryEvaluationException> iter)

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

Returns:

list

makeHashTable

protected Map<BindingSetHashKey,List<BindingSet>> makeHashTable(int initialSize)

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

Returns:

map

makeHashValue

protected List<BindingSet> makeHashValue(int currentMaxListSize)

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

Returns:

list

disposeCache

protected void disposeCache(Iterator<BindingSet> iter)

Utility methods to clear-up in case not using in-memory cache

disposeHashTable

protected void disposeHashTable(Map<BindingSetHashKey,List<BindingSet>> map)

Utility methods to clear-up in case not using in-memory hash table

closeHashValue

protected <E> void closeHashValue(Iterator<E> iter)

Utility methods to clear-up in case not using in-memory hash table

nextFromCache

protected <E> E nextFromCache(Iterator<E> iter)

add

protected <E> void add(Collection<E> col,
                       E value)
                throws QueryEvaluationException

Throws:

QueryEvaluationException

addAll

protected <E> void addAll(Collection<E> col,
                          List<E> values)
                   throws QueryEvaluationException

Throws:

QueryEvaluationException