Class HashTableResultSet

java.lang.Object

org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl

org.apache.derby.impl.sql.execute.NoPutResultSetImpl

org.apache.derby.impl.sql.execute.HashTableResultSet

All Implemented Interfaces:

CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

class HashTableResultSet
extends NoPutResultSetImpl
implements CursorResultSet

Builds a hash table on the underlying result set tree.

Nested Class Summary

Nested classes/interfaces inherited from class BasicNoPutResultSetImpl

BasicNoPutResultSetImpl.FieldComparator

Field Summary

Fields

Modifier and Type	Field	Description
private List	entryVector
private int	entryVectorSize
private boolean	firstIntoHashtable
private boolean	firstNext
private boolean	hashTableBuilt
int	hashtableSize
private BackingStoreHashtable	ht
private int	initialCapacity
int[]	keyColumns
private float	loadFactor
private ExecRow	mappedResultRow
private long	maxInMemoryRowCount
private ExecRow	nextCandidate
Qualifier[][]	nextQualifiers
private int	numFetchedOnNext
private GeneratedMethod	projection
long	projectionTime
private int[]	projectMapping
private ExecRow	projRow
private boolean	removeDuplicates
long	restrictionTime
boolean	reuseResult
private boolean	runTimeStatsOn
Properties	scanProperties
GeneratedMethod	singleTableRestriction
private boolean	skipNullKeyColumns
NoPutResultSet	source

Fields inherited from class NoPutResultSetImpl

checkNullCols, clonedExecRow, cncLen, resultSetNumber, targetResultSet

Fields inherited from class BasicNoPutResultSetImpl

activation, beginTime, closeTime, compactRow, constructorTime, currentRow, endExecutionTime, finished, isOpen, isTopResultSet, nextTime, numOpens, openTime, optimizerEstimatedCost, optimizerEstimatedRowCount, resultDescription, rowsFiltered, rowsSeen, startExecutionTime, subqueryTrackingArray

Fields inherited from interface NoPutResultSet

ABSOLUTE, FIRST, LAST, NEXT, PREVIOUS, RELATIVE, TEMPORARY_RESULT_SET_NUMBER

Fields inherited from interface ResultSet

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Constructor Summary

Constructors

Constructor	Description
HashTableResultSet(NoPutResultSet s, Activation a, GeneratedMethod str, Qualifier[][] nextQualifiers, GeneratedMethod p, int resultSetNumber, int mapRefItem, boolean reuseResult, int keyColItem, boolean removeDuplicates, long maxInMemoryRowCount, int initialCapacity, float loadFactor, boolean skipNullKeyColumns, double optimizerEstimatedRowCount, double optimizerEstimatedCost)

Method Summary

Modifier and Type	Method	Description
void	close()	If the result set has been opened, close the open scan.
private ExecRow	doProjection(ExecRow sourceRow)	Do the projection against the source row.
ExecRow	getCurrentRow()	Gets last row returned.
ExecRow	getNextRowCore()	Return the requested values computed from the next row (if any) for which the restriction evaluates to true.
DataValueDescriptor[]	getNextRowFromRowSource()	Get the next row as an array of column objects.
RowLocation	getRowLocation()	Gets information from its source.
long	getTimeSpent(int type)	Return the total amount of time spent in this ResultSet
boolean	isForUpdate()	Is this ResultSet or it's source result set for update
void	openCore()	open a scan on the table. scan parameters are evaluated at each open, so there is probably some way of altering their values...
void	reopenCore()	reopen a scan on the table. scan parameters are evaluated at each open, so there is probably some way of altering their values...
private void	resetProbeVariables()

Methods inherited from class NoPutResultSetImpl

clearCurrentRow, clearOrderableCache, closeRowSource, getCursorName, getResultDescription, getValidColumns, markRowAsDeleted, needsRowLocation, needsRowLocationForDeferredCheckConstraints, needsToClone, offendingRowLocation, positionScanAtRowLocation, printQualifiers, resultSetNumber, rowLocation, setCurrentRow, setHasDeferrableChecks, setNeedsRowLocation, setTargetResultSet, skipRow, skipScan, unpackHashValue, updateRow

Methods inherited from class BasicNoPutResultSetImpl

addWarning, attachStatementContext, checkCancellationFlag, checkRowPosition, childrenToXML, cleanUp, dumpTimeStats, finish, finishAndRTS, getAbsoluteRow, getActivation, getAutoGeneratedKeysResultset, getBeginExecutionTimestamp, getCompactRow, getCurrentTimeMillis, getElapsedMillis, getEndExecutionTimestamp, getEstimatedRowCount, getExecuteTime, getExecutionFactory, getFirstRow, getLanguageConnectionContext, getLastRow, getNextRow, getPointOfAttachment, getPreviousRow, getRelativeRow, getRowNumber, getScanIsolationLevel, getSubqueryTrackingArray, getTransactionController, getWarnings, isClosed, isXplainOnlyMode, markAsTopResultSet, modifiedRowCount, open, recordConstructorTime, requiresRelocking, returnsRows, setAfterLastRow, setBeforeFirstRow, setCompactRow, setCompatRow, toXML, toXML

Methods inherited from class Object

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

Methods inherited from interface ResultSet

addWarning, checkRowPosition, cleanUp, clearCurrentRow, finish, getAbsoluteRow, getActivation, getAutoGeneratedKeysResultset, getBeginExecutionTimestamp, getCursorName, getEndExecutionTimestamp, getExecuteTime, getFirstRow, getLastRow, getNextRow, getPreviousRow, getRelativeRow, getResultDescription, getRowNumber, getSubqueryTrackingArray, getWarnings, isClosed, modifiedRowCount, open, returnsRows, setAfterLastRow, setBeforeFirstRow, toXML

Field Details

restrictionTime

public long restrictionTime

projectionTime

public long projectionTime

hashtableSize

public int hashtableSize

scanProperties

public Properties scanProperties

source

public NoPutResultSet source

singleTableRestriction

public GeneratedMethod singleTableRestriction

nextQualifiers

public Qualifier[][] nextQualifiers

projection

private GeneratedMethod projection

projectMapping

private int[] projectMapping

runTimeStatsOn

private boolean runTimeStatsOn

mappedResultRow

private ExecRow mappedResultRow

reuseResult

public boolean reuseResult

keyColumns

public int[] keyColumns

removeDuplicates

private boolean removeDuplicates

maxInMemoryRowCount

private long maxInMemoryRowCount

initialCapacity

private int initialCapacity

loadFactor

private float loadFactor

skipNullKeyColumns

private boolean skipNullKeyColumns

firstNext

private boolean firstNext

numFetchedOnNext

private int numFetchedOnNext

entryVectorSize

private int entryVectorSize

entryVector

private List entryVector

hashTableBuilt

private boolean hashTableBuilt

firstIntoHashtable

private boolean firstIntoHashtable

nextCandidate

private ExecRow nextCandidate

projRow

private ExecRow projRow

ht

private BackingStoreHashtable ht

Constructor Details

HashTableResultSet

HashTableResultSet(NoPutResultSet s,
 Activation a,
 GeneratedMethod str,
 Qualifier[][] nextQualifiers,
 GeneratedMethod p,
 int resultSetNumber,
 int mapRefItem,
 boolean reuseResult,
 int keyColItem,
 boolean removeDuplicates,
 long maxInMemoryRowCount,
 int initialCapacity,
 float loadFactor,
 boolean skipNullKeyColumns,
 double optimizerEstimatedRowCount,
 double optimizerEstimatedCost)
            throws StandardException

Throws:

StandardException

Method Details

openCore

public void openCore()
              throws StandardException

open a scan on the table. scan parameters are evaluated at each open, so there is probably some way of altering their values...

Specified by:

openCore in interface NoPutResultSet

Throws:

StandardException - thrown if cursor finished.

reopenCore

public void reopenCore()
                throws StandardException

reopen a scan on the table. scan parameters are evaluated at each open, so there is probably some way of altering their values...

Specified by:

reopenCore in interface NoPutResultSet

Overrides:

reopenCore in class BasicNoPutResultSetImpl

Throws:

StandardException - thrown if cursor finished.

See Also:

• NoPutResultSet.openCore()

resetProbeVariables

private void resetProbeVariables()
                          throws StandardException

Throws:

StandardException

getNextRowCore

public ExecRow getNextRowCore()
                       throws StandardException

Return the requested values computed from the next row (if any) for which the restriction evaluates to true.

restriction and projection parameters are evaluated for each row.

Specified by:

getNextRowCore in interface NoPutResultSet

Specified by:

getNextRowCore in class BasicNoPutResultSetImpl

Returns:

the next row in the result

Throws:

StandardException - thrown on failure.

StandardException - ResultSetNotOpen thrown if not yet open.

See Also:

• NoPutResultSet.getNextRowCore()

getTimeSpent

public long getTimeSpent(int type)

Return the total amount of time spent in this ResultSet

Specified by:

getTimeSpent in interface ResultSet

Parameters:

type - CURRENT_RESULTSET_ONLY - time spent only in this ResultSet ENTIRE_RESULTSET_TREE - time spent in this ResultSet and below.

Returns:

long The total amount of time spent (in milliseconds).

close

public void close()
           throws StandardException

If the result set has been opened, close the open scan.

Specified by:

close in interface ResultSet

Overrides:

close in class NoPutResultSetImpl

Throws:

StandardException - thrown on error

getRowLocation

public RowLocation getRowLocation()
                           throws StandardException

Gets information from its source. We might want to have this take a CursorResultSet in its constructor some day, instead of doing a cast here?

Specified by:

getRowLocation in interface CursorResultSet

Returns:

the row location of the current cursor row.

Throws:

StandardException - thrown on failure.

See Also:

• CursorResultSet

getCurrentRow

public ExecRow getCurrentRow()
                      throws StandardException

Gets last row returned.

Specified by:

getCurrentRow in interface CursorResultSet

Returns:

the last row returned.

Throws:

StandardException - thrown on failure.

See Also:

• CursorResultSet

doProjection

private ExecRow doProjection(ExecRow sourceRow)
                      throws StandardException

Do the projection against the source row. Use reflection where necessary, otherwise get the source column into our result row.

Parameters:

sourceRow - The source row.

Returns:

The result of the projection

Throws:

StandardException - thrown on failure.

getNextRowFromRowSource

public DataValueDescriptor[] getNextRowFromRowSource()
                                              throws StandardException

Description copied from interface: RowSource

Get the next row as an array of column objects. The column objects can be a JBMS Storable or any Serializable/Externalizable/Formattable/Streaming type.
A return of null indicates that the complete set of rows has been read.

A null column can be specified by leaving the object null, or indicated by returning a non-null getValidColumns. On streaming columns, it can be indicated by returning a non-null get FieldStates.

If RowSource.needToClone() is true then the returned row (the DataValueDescriptor[]) is guaranteed not to be modified by drainer of the RowSource (except that the input stream will be read, of course) and drainer will keep no reference to it before making the subsequent nextRow call. So it is safe to return the same DataValueDescriptor[] in subsequent nextRow calls if that is desirable for performance reasons.

If RowSource.needToClone() is false then the returned row (the DataValueDescriptor[]) may be be modified by drainer of the RowSource, and the drainer may keep a reference to it after making the subsequent nextRow call. In this case the client should severe all references to the row after returning it from getNextRowFromRowSource().

Specified by:

getNextRowFromRowSource in interface RowSource

Overrides:

getNextRowFromRowSource in class NoPutResultSetImpl

Throws:

StandardException - on error

See Also:

• RowSource.getNextRowFromRowSource()

isForUpdate

public boolean isForUpdate()

Is this ResultSet or it's source result set for update

Specified by:

isForUpdate in interface NoPutResultSet

Overrides:

isForUpdate in class NoPutResultSetImpl

Returns:

Whether or not the result set is for update.