org.apache.derby.impl.sql.execute
Class WindowResultSet

java.lang.Object
  org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl
      org.apache.derby.impl.sql.execute.NoPutResultSetImpl
          org.apache.derby.impl.sql.execute.WindowResultSet

All Implemented Interfaces:

NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

 class WindowResultSet
extends NoPutResultSetImpl

WindowResultSet This ResultSet handles a window function ResultSet. The ResultSet is opened using openCore(). Each row is fetched and any restrictions evaluated for each row in a do-while loop in getNextRowCore(). The ResultSet is closed using closeCore().

Field Summary

private ExecRow	allocatedRow
private FormatableBitSet	referencedColumns
private GeneratedMethod	restriction
long	restrictionTime Cumulative time needed to evaluate any restriction on this result set.
private long	rownumber
NoPutResultSet	source Source result set,

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

WindowResultSet(Activation activation, NoPutResultSet source, int rowAllocator, int resultSetNumber, int erdNumber, GeneratedMethod restriction, double optimizerEstimatedRowCount, double optimizerEstimatedCost)
Constructor

Method Summary

void	close() If the result set has been opened, close the open scan, else throw.
private ExecRow	getAllocatedRow() Cache the ExecRow for this result set.
ExecRow	getNextRowCore() Return the requested values computed from the next row (if any) for which the restriction evaluates to true.
long	getTimeSpent(int type) Return the total amount of time spent in this ResultSet
void	openCore() Open this ResultSet.
void	populateFromSourceRow(ExecRow srcrow, ExecRow destrow) Copy columns from srcrow into destrow, or insert ROW_NUMBER.
void	reopenCore() Reopen this ResultSet.

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

clearCurrentRow, clearOrderableCache, 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, 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, markAsTopResultSet, modifiedRowCount, open, recordConstructorTime, requiresRelocking, returnsRows, setAfterLastRow, setBeforeFirstRow, setCompactRow, setCompatRow

Methods inherited from class java.lang.Object

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

Field Detail

restriction

private GeneratedMethod restriction

source

public NoPutResultSet source

Source result set,

restrictionTime

public long restrictionTime

Cumulative time needed to evaluate any restriction on this result set.

referencedColumns

private FormatableBitSet referencedColumns

allocatedRow

private ExecRow allocatedRow

rownumber

private long rownumber

Constructor Detail

WindowResultSet

WindowResultSet(Activation activation,
                NoPutResultSet source,
                int rowAllocator,
                int resultSetNumber,
                int erdNumber,
                GeneratedMethod restriction,
                double optimizerEstimatedRowCount,
                double optimizerEstimatedCost)
          throws StandardException

Constructor

Parameters:

activation - The activation

source - Source result set

rowAllocator -

resultSetNumber - The resultSetNumber

erdNumber - Int for ResultDescription (so it can be turned back into an object)

restriction - Restriction

optimizerEstimatedRowCount - The optimizer's estimated number of rows.

optimizerEstimatedCost - The optimizer's estimated cost

Throws:

StandardException

Method Detail

openCore

public void openCore()
              throws StandardException

Open this ResultSet.

Throws:

StandardException - thrown if cursor finished.

reopenCore

public void reopenCore()
                throws StandardException

Reopen this ResultSet.

Specified by:

reopenCore in interface NoPutResultSet

Overrides:

reopenCore in class BasicNoPutResultSetImpl

Throws:

StandardException - thrown if cursor finished.

See Also:

NoPutResultSet.openCore()

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()

close

public void close()
           throws StandardException

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

Specified by:

close in interface ResultSet

Overrides:

close in class NoPutResultSetImpl

Throws:

StandardException - thrown on error

populateFromSourceRow

public void populateFromSourceRow(ExecRow srcrow,
                                  ExecRow destrow)
                           throws StandardException

Copy columns from srcrow into destrow, or insert ROW_NUMBER.

FIXME This is temporary. Window function treatment needs to generalized to work for other window functions.

Throws:

StandardException - thrown on failure to open

getTimeSpent

public long getTimeSpent(int type)

Return the total amount of time spent in this 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).

getAllocatedRow

private ExecRow getAllocatedRow()
                         throws StandardException

Cache the ExecRow for this result set.

Returns:

The cached ExecRow for this ResultSet

Throws:

StandardException - thrown on failure.