org.apache.derby.impl.sql.execute

Class GenericAggregateResultSet

java.lang.Object

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

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

org.apache.derby.impl.sql.execute.GenericAggregateResultSet

All Implemented Interfaces:

NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

Direct Known Subclasses:

GroupedAggregateResultSet, ScalarAggregateResultSet

abstract class GenericAggregateResultSet
extends NoPutResultSetImpl

Generic aggregation utilities.

Field Summary

Fields

Modifier and Type	Field and Description
protected AggregatorInfoList	aggInfoList
protected GenericAggregator[]	aggregates
protected NoPutResultSet	originalSource
private ExecIndexRow	rowTemplate
NoPutResultSet	source

Fields inherited from class org.apache.derby.impl.sql.execute.NoPutResultSetImpl

checkNullCols, clonedExecRow, cncLen, resultSetNumber, targetResultSet

Fields inherited from class org.apache.derby.impl.sql.execute.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 org.apache.derby.iapi.sql.execute.NoPutResultSet

ABSOLUTE, FIRST, LAST, NEXT, PREVIOUS, RELATIVE

Fields inherited from interface org.apache.derby.iapi.sql.ResultSet

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Constructor Summary

Constructors

Constructor and Description
GenericAggregateResultSet(NoPutResultSet s, int aggregateItem, Activation a, int ra, int resultSetNumber, double optimizerEstimatedRowCount, double optimizerEstimatedCost) Constructor

Method Summary

Modifier and Type	Method and Description
void	finish() Tells the system that there will be no more access to any database information via this result set; in particular, no more calls to open().
protected ExecIndexRow	finishAggregation(ExecIndexRow row) Finish the aggregation for the current row.
(package private) ExecIndexRow	getRowTemplate() Get a template row of the right shape for sorting or returning results.
protected GenericAggregator[]	getSortAggregators(AggregatorInfoList list, boolean eliminateDistincts, LanguageConnectionContext lcc, NoPutResultSet inputResultSet) For each AggregatorInfo in the list, generate a GenericAggregator and stick it in an array of GenericAggregators.

Methods inherited from class org.apache.derby.impl.sql.execute.NoPutResultSetImpl

clearCurrentRow, clearOrderableCache, close, closeRowSource, getCursorName, getNextRowFromRowSource, getResultDescription, getValidColumns, isForUpdate, markRowAsDeleted, needsRowLocation, needsToClone, positionScanAtRowLocation, printQualifiers, resultSetNumber, rowLocation, setCurrentRow, setNeedsRowLocation, setTargetResultSet, skipRow, skipScan, updateRow

Methods inherited from class org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl

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

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.derby.iapi.sql.execute.NoPutResultSet

openCore

Methods inherited from interface org.apache.derby.iapi.sql.ResultSet

getTimeSpent

Field Detail

aggregates

protected GenericAggregator[] aggregates

aggInfoList

protected AggregatorInfoList aggInfoList

source

public NoPutResultSet source

originalSource

protected NoPutResultSet originalSource

rowTemplate

private final ExecIndexRow rowTemplate

Constructor Detail

GenericAggregateResultSet

GenericAggregateResultSet(NoPutResultSet s,
                          int aggregateItem,
                          Activation a,
                          int ra,
                          int resultSetNumber,
                          double optimizerEstimatedRowCount,
                          double optimizerEstimatedCost)
                   throws StandardException

Constructor

Parameters:

a - activation

ra - reference to a saved row allocator instance

resultSetNumber - result set number

optimizerEstimatedRowCount - optimizer estimated row count

optimizerEstimatedCost - optimizer estimated cost

Throws:

StandardException - Thrown on error

Method Detail

getRowTemplate

ExecIndexRow getRowTemplate()

Get a template row of the right shape for sorting or returning results. The template is cached, so it may need to be cloned if callers use it for multiple purposes at the same time.

Returns:

a row template of the right shape for this result set

getSortAggregators

protected final GenericAggregator[] getSortAggregators(AggregatorInfoList list,
                                                       boolean eliminateDistincts,
                                                       LanguageConnectionContext lcc,
                                                       NoPutResultSet inputResultSet)
                                                throws StandardException

For each AggregatorInfo in the list, generate a GenericAggregator and stick it in an array of GenericAggregators.

Parameters:

list - the list of aggregators to set up

eliminateDistincts - should distincts be ignored. Used to toss out distinct aggregates for a prelim sort.

lcc - the lcc

inputResultSet - the incoming result set

Returns:

the array of GenericAggregators

Throws:

StandardException - on error

finishAggregation

protected final ExecIndexRow finishAggregation(ExecIndexRow row)
                                        throws StandardException

Finish the aggregation for the current row. Basically call finish() on each aggregator on this row. Called once per grouping on a vector aggregate or once per table on a scalar aggregate. If the input row is null, then rowAllocator is invoked to create a new row. That row is then initialized and used for the output of the aggregation.

Parameters:

row - the row to finish aggregation

Returns:

the result row. If the input row != null, then the result row == input row

Throws:

StandardException - Thrown on error

finish

public void finish()
            throws StandardException

Description copied from interface: ResultSet

Tells the system that there will be no more access to any database information via this result set; in particular, no more calls to open(). Will close the result set if it is not already closed.

Specified by:

finish in interface ResultSet

Overrides:

finish in class BasicNoPutResultSetImpl

Throws:

StandardException - on error