org.modeshape.jcr.query.engine.process

Class DependentQuery

java.lang.Object

org.modeshape.jcr.query.NodeSequence

org.modeshape.jcr.query.engine.process.DependentQuery

public class DependentQuery
extends NodeSequence

A node sequence implementation that performs an independent query to find results that are required for a dependent query. At this time, all of the results of the first query are kept in-memory, and stored in a variable where it is then accessed by the dependent query.

Nested Class Summary

Nested classes/interfaces inherited from class org.modeshape.jcr.query.NodeSequence

NodeSequence.AlternateSizeBatch, NodeSequence.Batch, NodeSequence.LimitBatch, NodeSequence.MultiWidthBatch, NodeSequence.Restartable, NodeSequence.RowAccessor, NodeSequence.RowFilter, NodeSequence.SingleWidthBatch

Field Summary

Fields

Modifier and Type	Field and Description
protected static Logger	logger

Fields inherited from class org.modeshape.jcr.query.NodeSequence

LOGGER, NO_PASS_ROW_FILTER, PASS_ROW_FILTER

Constructor Summary

Constructors

Constructor and Description
DependentQuery(NodeSequence independentQuery, RowExtractors.ExtractFromRow independentQueryValueExtractor, TypeSystem.TypeFactory<?> expectedType, NodeSequence dependentQuery, String variableName, Map<String,Object> variables)

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Signal that this node sequence is no longer needed.
long	getRowCount() Get the number of rows in this sequence.
protected void	initialize()
boolean	isEmpty() Determine whether this results is known to be empty.
NodeSequence.Batch	nextBatch() Get the next batch of NodeKey instances.
int	width() Get the number of nodes in each row.

Methods inherited from class org.modeshape.jcr.query.NodeSequence

append, batchFilteredWith, batchOf, batchOf, batchOf, batchOfKeys, batchOfKeys, batchOfKeys, batchOfKeys, batchWithCount, copy, emptyBatch, emptySequence, filter, keyFor, limit, limit, merging, requireBoth, requireEither, skip, withBatch, withBatches, withBatches, withNode, withNodeKeys, withNodeKeys, withNodeKeys, withNodeKeys, withNodes, withNodes

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected static final Logger logger

Constructor Detail

DependentQuery

public DependentQuery(NodeSequence independentQuery,
              RowExtractors.ExtractFromRow independentQueryValueExtractor,
              TypeSystem.TypeFactory<?> expectedType,
              NodeSequence dependentQuery,
              String variableName,
              Map<String,Object> variables)

Method Detail

getRowCount

public long getRowCount()

Description copied from class: NodeSequence

Get the number of rows in this sequence. If the actual number of rows is not known, this method returns -1.

Specified by:

getRowCount in class NodeSequence

Returns:

the number of rows, or -1 if the number of rows is not known or cannot be found with significant overhead

width

public int width()

Description copied from class: NodeSequence

Get the number of nodes in each row.

Specified by:

width in class NodeSequence

Returns:

the width of each row; always positive

isEmpty

public boolean isEmpty()

Description copied from class: NodeSequence

Determine whether this results is known to be empty.

Specified by:

isEmpty in class NodeSequence

Returns:

the true if there are no results, or false if there is at least some or if the number of rows is not known

nextBatch

public NodeSequence.Batch nextBatch()

Description copied from class: NodeSequence

Get the next batch of NodeKey instances.

Specified by:

nextBatch in class NodeSequence

Returns:

the next batch, or null if there are no more batches.

initialize

protected void initialize()

close

public void close()

Description copied from class: NodeSequence

Signal that this node sequence is no longer needed.

Specified by:

close in class NodeSequence