Package org.eclipse.rdf4j.query.algebra.evaluation.iterator

Class HashJoinIteration

java.lang.Object

org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration<BindingSet>

org.eclipse.rdf4j.common.iteration.LookAheadIteration<BindingSet>

org.eclipse.rdf4j.query.algebra.evaluation.iterator.HashJoinIteration

All Implemented Interfaces:

AutoCloseable, Iterator<BindingSet>, CloseableIteration<BindingSet>

public class HashJoinIteration
extends LookAheadIteration<BindingSet>

Generic hash join implementation suitable for use by Sail implementations.

Author:

MJAHale

Field Summary

Fields

Modifier and Type	Field	Description
protected final String[]	joinAttributes

Constructor Summary

Constructors

Constructor	Description
HashJoinIteration(CloseableIteration<BindingSet> leftIter, Set<String> leftBindingNames, CloseableIteration<BindingSet> rightIter, Set<String> rightBindingNames, boolean leftJoin)	Deprecated, for removal: This API element is subject to removal in a future version.
HashJoinIteration(QueryEvaluationStep left, QueryEvaluationStep right, BindingSet bindings, boolean leftJoin, String[] joinAttributes, QueryEvaluationContext context)

Method Summary

Modifier and Type	Method	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 AbstractCloseableIteration.close() when it is called for the first time.
static String[]	hashJoinAttributeNames(Join join)
static String[]	hashJoinAttributeNames(LeftJoin join)
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> 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>> nextHashTable, BindingSetHashKey hashKey, List<BindingSet> hashValue, boolean newEntry)

Methods inherited from class org.eclipse.rdf4j.common.iteration.LookAheadIteration

hasNext, next, remove

Methods inherited from class org.eclipse.rdf4j.common.iteration.AbstractCloseableIteration

close, isClosed

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.eclipse.rdf4j.common.iteration.CloseableIteration

stream

Methods inherited from interface java.util.Iterator

forEachRemaining

Field Details

joinAttributes

protected final String[] joinAttributes

Constructor Details

HashJoinIteration

public HashJoinIteration(QueryEvaluationStep left,
 QueryEvaluationStep right,
 BindingSet bindings,
 boolean leftJoin,
 String[] joinAttributes,
 QueryEvaluationContext context)
                  throws QueryEvaluationException

Throws:

QueryEvaluationException

HashJoinIteration

@Deprecated(since="5.0.0",
            forRemoval=true)
public HashJoinIteration(CloseableIteration<BindingSet> leftIter,
 Set<String> leftBindingNames,
 CloseableIteration<BindingSet> rightIter,
 Set<String> rightBindingNames,
 boolean leftJoin)
                  throws QueryEvaluationException

Deprecated, for removal: This API element is subject to removal in a future version.

Throws:

QueryEvaluationException

Method Details

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>

Returns:

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

Throws:

QueryEvaluationException

handleClose

protected void handleClose()
                    throws QueryEvaluationException

Description copied from class: AbstractCloseableIteration

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

Specified by:

handleClose in class AbstractCloseableIteration<BindingSet>

Throws:

QueryEvaluationException

putHashTableEntry

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

Throws:

QueryEvaluationException

makeIterationCache

protected Collection<BindingSet> makeIterationCache(CloseableIteration<BindingSet> 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

hashJoinAttributeNames

public static String[] hashJoinAttributeNames(Join join)

hashJoinAttributeNames

public static String[] hashJoinAttributeNames(LeftJoin join)