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

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

All Implemented Interfaces:

CursorResultSet, NoPutResultSet, ResultSet, RowLocationRetRowSource, RowSource

 class CurrentOfResultSet
extends NoPutResultSetImpl
implements CursorResultSet

Takes a cursor name and returns the current row of the cursor; for use in generating the source row and row location for positioned update/delete operations.

This result set returns only one row.

Field Summary

private CursorResultSet	cursor
private java.lang.String	cursorName
private boolean	next
private RowLocation	rowLocation
private ExecRow	sparseRow
private CursorResultSet	target

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.ResultSet

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

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

ABSOLUTE, FIRST, LAST, NEXT, PREVIOUS, RELATIVE

Constructor Summary

CurrentOfResultSet(java.lang.String cursorName, Activation activation, int resultSetNumber)

Method Summary

void	close() If the result set has been opened, close the open scan.
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().
ExecRow	getCurrentRow() Returns the current row of the result set.
private void	getCursor() Because the positioned operation only gets one location per execution, and the cursor could be completely different for each execution (closed and reopened, perhaps), we determine where caching the cursor could be applied.
ExecRow	getNextRowCore() If open and not returned yet, returns the row.
RowLocation	getRowLocation() This result set has its row location from the last fetch done.
private ExecRow	getSparseRow(ExecRow row, int[] indexCols) Return a sparse heap row, based on a compact index row.
long	getTimeSpent(int type) Return the total amount of time spent in this ResultSet
void	markRowAsDeleted() Marks the resultSet's currentRow as deleted after a delete has been issued by either by using positioned delete or JDBC's deleteRow method.
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	updateRow(ExecRow row, RowChanger rowChanger) Updates the resultSet's current row with it's new values after an update has been issued either using positioned update or JDBC's udpateRow method.

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

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

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, getPointOfAttachment, getPreviousRow, getRelativeRow, getRowNumber, getScanIsolationLevel, getSubqueryTrackingArray, getTransactionController, getWarnings, isClosed, 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.ResultSet

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

Field Detail

next

private boolean next

rowLocation

private RowLocation rowLocation

cursor

private CursorResultSet cursor

target

private CursorResultSet target

sparseRow

private ExecRow sparseRow

cursorName

private final java.lang.String cursorName

Constructor Detail

CurrentOfResultSet

CurrentOfResultSet(java.lang.String cursorName,
                   Activation activation,
                   int resultSetNumber)

Method Detail

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 on failure to open

getNextRowCore

public ExecRow getNextRowCore()
                       throws StandardException

If open and not returned yet, returns the 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.

See Also:

NoPutResultSet.getNextRowCore()

getSparseRow

private ExecRow getSparseRow(ExecRow row,
                             int[] indexCols)
                      throws StandardException

Return a sparse heap row, based on a compact index row.

Parameters:

row - compact referenced index row

indexCols - base column positions of index keys, signed with asc/desc info

Returns:

a sparse heap row with referenced columns

Throws:

StandardException

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

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

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).

getRowLocation

public RowLocation getRowLocation()

This result set has its row location from the last fetch done. If it is closed, a null is returned.

Specified by:

getRowLocation in interface CursorResultSet

Returns:

the row location of the current row.

Throws:

StandardException - thrown on failure to get row location

See Also:

CursorResultSet

getCurrentRow

public ExecRow getCurrentRow()

Description copied from interface: CursorResultSet

Returns the current row of the result set. REMIND: eventually, this will only return the current row for result sets that need to return it; either some field in the activation or a parameter in the constructor will be used to signal that this needs to function. This will let us limit the number of live objects we are holding on to.

Specified by:

getCurrentRow in interface CursorResultSet

Returns:

the last row returned by getNextRow.

See Also:

CursorResultSet

getCursor

private void getCursor()
                throws StandardException

Because the positioned operation only gets one location per execution, and the cursor could be completely different for each execution (closed and reopened, perhaps), we determine where caching the cursor could be applied.

When cached, we check if the cursor was closed'd, and if so, throw it out and see if there's one in the cache with our name.

Throws:

StandardException

updateRow

public void updateRow(ExecRow row,
                      RowChanger rowChanger)
               throws StandardException

Description copied from interface: NoPutResultSet

Updates the resultSet's current row with it's new values after an update has been issued either using positioned update or JDBC's udpateRow method.

Specified by:

updateRow in interface NoPutResultSet

Overrides:

updateRow in class NoPutResultSetImpl

Parameters:

row - new values for the currentRow

rowChanger - holds information about row: what columns of it is to be used for updating, and what underlying base table column each such column corresponds to.

Throws:

StandardException - thrown on failure.

See Also:

NoPutResultSet.updateRow(org.apache.derby.iapi.sql.execute.ExecRow, org.apache.derby.iapi.sql.execute.RowChanger)

markRowAsDeleted

public void markRowAsDeleted()
                      throws StandardException

Description copied from interface: NoPutResultSet

Marks the resultSet's currentRow as deleted after a delete has been issued by either by using positioned delete or JDBC's deleteRow method.

Specified by:

markRowAsDeleted in interface NoPutResultSet

Overrides:

markRowAsDeleted in class NoPutResultSetImpl

Throws:

StandardException - thrown on failure.

See Also:

NoPutResultSet.markRowAsDeleted()