org.modeshape.jcr.query.engine.process

Class CountableSequence

java.lang.Object

org.modeshape.jcr.query.NodeSequence

org.modeshape.jcr.query.engine.process.CountableSequence

Direct Known Subclasses:

PartialMemoryCountableSequence

public class CountableSequence
extends NodeSequence

A sequence that will return an accurate size for a given NodeSequence by buffering and counting the nodes and then accessing the buffered sequence.

See Also:

PartialMemoryCountableSequence

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 AtomicLong	remainingRowCount
protected int	width
protected String	workspaceName

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

LOGGER, NO_PASS_ROW_FILTER, PASS_ROW_FILTER

Constructor Summary

Constructors

Constructor and Description
CountableSequence(String workspaceName, NodeSequence original, BufferManager bufferMgr, CachedNodeSupplier nodeCache, boolean useHeap)

Method Summary

Modifier and Type	Method and Description
protected NodeSequence.Batch	batchFrom(Iterator<BufferedRows.BufferedRow> rows, long maxBatchSize)
void	close() Signal that this node sequence is no longer needed.
protected BufferedRows.BufferedRow	createRow(NodeSequence.Batch currentRow)
protected void	doInitialize()
protected NodeSequence.Batch	doNextBatch()
long	getRowCount() Get the number of rows in this sequence.
void	initialize()
boolean	isEmpty() Determine whether this results is known to be empty.
protected long	loadAll(NodeSequence sequence, BufferManager.QueueBuffer<BufferedRows.BufferedRow> buffer, AtomicLong batchSize) Load all of the rows from the supplied sequence into the buffer.
protected long	loadAll(NodeSequence sequence, BufferManager.QueueBuffer<BufferedRows.BufferedRow> buffer, AtomicLong batchSize, Queue<NodeSequence.Batch> inMemoryBatches, int numRowsInMemory) Load all of the rows from the supplied sequence into the buffer.
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, 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, toString, wait, wait, wait

Field Detail

remainingRowCount

protected final AtomicLong remainingRowCount

workspaceName

protected final String workspaceName

width

protected final int width

Constructor Detail

CountableSequence

public CountableSequence(String workspaceName,
                         NodeSequence original,
                         BufferManager bufferMgr,
                         CachedNodeSupplier nodeCache,
                         boolean useHeap)

Method Detail

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

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

nextBatch

public final 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.

doNextBatch

protected NodeSequence.Batch doNextBatch()

close

public void close()

Description copied from class: NodeSequence

Signal that this node sequence is no longer needed.

Specified by:

close in class NodeSequence

initialize

public final void initialize()

doInitialize

protected void doInitialize()

loadAll

protected long loadAll(NodeSequence sequence,
                       BufferManager.QueueBuffer<BufferedRows.BufferedRow> buffer,
                       AtomicLong batchSize)

Load all of the rows from the supplied sequence into the buffer.

Parameters:

sequence - the node sequence; may not be null

buffer - the buffer into which all rows should be loaded; may not be null

batchSize - the atomic that should be set with the size of the first batch

Returns:

the total number of rows

loadAll

protected long loadAll(NodeSequence sequence,
                       BufferManager.QueueBuffer<BufferedRows.BufferedRow> buffer,
                       AtomicLong batchSize,
                       Queue<NodeSequence.Batch> inMemoryBatches,
                       int numRowsInMemory)

Load all of the rows from the supplied sequence into the buffer.

Parameters:

sequence - the node sequence; may not be null

buffer - the buffer into which all rows should be loaded; may not be null

batchSize - the atomic that should be set with the size of the first batch

inMemoryBatches - the queue into which batches that are kept in-memory; may be null, in which case all batches are placed into the buffer

numRowsInMemory - the approximate number of rows that should be kept in-memory; may be non-positive if all batches are to be placed into the buffer

Returns:

the total number of rows

createRow

protected BufferedRows.BufferedRow createRow(NodeSequence.Batch currentRow)

batchFrom

protected NodeSequence.Batch batchFrom(Iterator<BufferedRows.BufferedRow> rows,
                                       long maxBatchSize)