org.apache.jackrabbit.core.query.lucene.join
Class Join

java.lang.Object
  org.apache.jackrabbit.core.query.lucene.join.Join

All Implemented Interfaces:

CloseableHits, MultiColumnQueryHits

public class Join
extends Object
implements MultiColumnQueryHits

Join implements the result of a join.

Field Summary

protected List<ScoreNode[]>	buffer A buffer for joined score node rows.
protected Condition	condition The join condition.
protected ScoreNode[]	emptyInnerHits An array of empty inner query hits.
protected boolean	innerJoin Whether this is an inner join.
protected MultiColumnQueryHits	outer The outer query hits.
protected int	outerScoreNodeIndex The score node index of the outer query hits.
protected Name[]	selectorNames The selector names.

Method Summary

void	close() Releases resources held by this hits instance.
static Join	create(MultiColumnQueryHits left, MultiColumnQueryHits right, JoinType joinType, JoinConditionImpl condition, org.apache.lucene.index.IndexReader reader, HierarchyResolver resolver, NamespaceMappings nsMappings, HierarchyManager hmgr) Creates a new join result.
protected static int	getIndex(MultiColumnQueryHits source, Name selectorName) Returns the index of the selector with the given selectorName within the given source.
Name[]	getSelectorNames()
int	getSize() This default implementation always returns -1.
protected static MultiColumnQueryHits	getSourceWithName(Name selectorName, MultiColumnQueryHits left, MultiColumnQueryHits right)
ScoreNode[]	nextScoreNodes() Returns the next score nodes in this QueryHits or null if there are no more score nodes.
void	skip(int n) Skips a n score nodes.

Methods inherited from class java.lang.Object

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

Field Detail

outer

protected final MultiColumnQueryHits outer

The outer query hits.

outerScoreNodeIndex

protected final int outerScoreNodeIndex

The score node index of the outer query hits.

innerJoin

protected final boolean innerJoin

Whether this is an inner join.

condition

protected final Condition condition

The join condition.

selectorNames

protected final Name[] selectorNames

The selector names.

emptyInnerHits

protected final ScoreNode[] emptyInnerHits

An array of empty inner query hits.

buffer

protected final List<ScoreNode[]> buffer

A buffer for joined score node rows.

Method Detail

create

public static Join create(MultiColumnQueryHits left,
                          MultiColumnQueryHits right,
                          JoinType joinType,
                          JoinConditionImpl condition,
                          org.apache.lucene.index.IndexReader reader,
                          HierarchyResolver resolver,
                          NamespaceMappings nsMappings,
                          HierarchyManager hmgr)
                   throws IOException

Creates a new join result.

Parameters:

left - the left query hits.

right - the right query hits.

joinType - the join type.

condition - the QOM join condition.

reader - the index reader.

resolver - the hierarchy resolver.

nsMappings - namespace mappings of this index

hmgr - the hierarchy manager of the workspace.

Returns:

the join result.

Throws:

IOException - if an error occurs while executing the join.

nextScoreNodes

public ScoreNode[] nextScoreNodes()
                           throws IOException

Returns the next score nodes in this QueryHits or null if there are no more score nodes.

Specified by:

nextScoreNodes in interface MultiColumnQueryHits

Returns:

the next score nodes in this QueryHits.

Throws:

IOException - if an error occurs while reading from the index.

getSelectorNames

public Name[] getSelectorNames()

Specified by:

getSelectorNames in interface MultiColumnQueryHits

Returns:

the selector names that correspond to the ScoreNodes returned by MultiColumnQueryHits.nextScoreNodes().

close

public void close()
           throws IOException

Releases resources held by this hits instance. Closes outer source and the condition.

Specified by:

close in interface CloseableHits

Throws:

IOException - if an error occurs while releasing resources.

getSize

public int getSize()

This default implementation always returns -1.

Specified by:

getSize in interface CloseableHits

Returns:

always -1.

skip

public void skip(int n)
          throws IOException

Skips a n score nodes. Skips by calling nextScoreNodes() n times. Sub classes may provide a more performance implementation.

Specified by:

skip in interface CloseableHits

Parameters:

n - the number of score nodes to skip.

Throws:

IOException - if an error occurs while skipping.

getSourceWithName

protected static MultiColumnQueryHits getSourceWithName(Name selectorName,
                                                        MultiColumnQueryHits left,
                                                        MultiColumnQueryHits right)

getIndex

protected static int getIndex(MultiColumnQueryHits source,
                              Name selectorName)

Returns the index of the selector with the given selectorName within the given source.

Parameters:

source - a source.

selectorName - a selector name.

Returns:

the index within the source or -1 if the name does not exist in source.