org.modeshape.jcr.query.engine.process

Class DistinctSequence

java.lang.Object

org.modeshape.jcr.query.NodeSequence

org.modeshape.jcr.query.engine.process.DelegatingSequence

org.modeshape.jcr.query.engine.process.DistinctSequence

public class DistinctSequence
extends DelegatingSequence

A NodeSequence that wraps another NodeSequence and returns only those rows that are seen for the first time.

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 RowExtractors.ExtractFromRow	keyExtractor
protected static Logger	LOGGER
protected boolean	trace

Fields inherited from class org.modeshape.jcr.query.engine.process.DelegatingSequence

delegate

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

NO_PASS_ROW_FILTER, PASS_ROW_FILTER

Constructor Summary

Constructors

Constructor and Description
DistinctSequence(NodeSequence delegate, TypeSystem types, BufferManager bufferMgr, boolean useHeap) Create a new distinct sequence given the type system and buffer manager.

Method Summary

Modifier and Type	Method and Description
NodeSequence.Batch	nextBatch() Get the next batch of NodeKey instances.
String	toString()

Methods inherited from class org.modeshape.jcr.query.engine.process.DelegatingSequence

close, getRowCount, isEmpty, width

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, slice, slicingBatch, withBatch, withBatches, withBatches, withNode, withNodeKeys, withNodeKeys, withNodeKeys, withNodeKeys, withNodes, withNodes

Methods inherited from class java.lang.Object

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

Field Detail

LOGGER

protected static final Logger LOGGER

keyExtractor

protected final RowExtractors.ExtractFromRow keyExtractor

trace

protected final boolean trace

Constructor Detail

DistinctSequence

public DistinctSequence(NodeSequence delegate,
                        TypeSystem types,
                        BufferManager bufferMgr,
                        boolean useHeap)

Create a new distinct sequence given the type system and buffer manager.

Parameters:

delegate - the node sequence that is to be wrapped; may not be null

types - the system of type factories; may not be null

bufferMgr - the buffer manager that should be used to create a temporary buffer into which records of the rows can be kept; may not be null

useHeap - true if the temporary buffer should use the heap, or false if it should store data off-heap

Method Detail

nextBatch

public NodeSequence.Batch nextBatch()

Description copied from class: NodeSequence

Get the next batch of NodeKey instances.

Overrides:

nextBatch in class DelegatingSequence

Returns:

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

toString

public String toString()

Overrides:

toString in class Object