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

java.lang.Object
  org.apache.derby.impl.sql.execute.NoRowsResultSetImpl

All Implemented Interfaces:

ResultSet

Direct Known Subclasses:

CallStatementResultSet, DMLWriteResultSet, MiscResultSet

abstract class NoRowsResultSetImpl
extends java.lang.Object
implements ResultSet

Abstract ResultSet for implementations that do not return rows. Examples are DDL statements, CALL statements and DML.

An implementation must provide a ResultSet.open() method that performs the required action.

ResultSet.returnsRows() returns false and any method that fetches a row will throw an exception.

Field Summary

(package private) Activation	activation
protected long	beginExecutionTime
protected long	beginTime
protected long	endExecutionTime
protected long	endTime
private int	firstColumn
private int[]	generatedColumnPositions
private boolean	isOpen True if the result set has been opened, and not yet closed.
(package private) LanguageConnectionContext	lcc
private DataValueDescriptor[]	normalizedGeneratedValues
private boolean	statisticsTimingOn
private NoPutResultSet[]	subqueryTrackingArray

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

CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Constructor Summary

NoRowsResultSetImpl(Activation activation)

Method Summary

void	addWarning(java.sql.SQLWarning w) Add a warning to this result set.
boolean	checkRowPosition(int isType) Determine if the cursor is before the first row in the result set.
void	clearCurrentRow() Clear the current row.
void	close() Dump the stat if not already done so.
boolean	doesCommit() Does this ResultSet cause a commit or rollback.
static void	evaluateACheckConstraint(GeneratedMethod checkGM, java.lang.String checkName, long heapConglom, Activation activation) Run a check constraint against the current row.
static void	evaluateCheckConstraints(GeneratedMethod checkGM, Activation activation) Run check constraints against the current row.
void	evaluateGenerationClauses(GeneratedMethod generationClauses, Activation activation, NoPutResultSet source, ExecRow newRow, boolean isUpdate) Compute the generation clauses on the current row in order to fill in computed columns.
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	getAbsoluteRow(int row) Returns the row at the absolute position from the query, and returns NULL when there is no such position.
Activation	getActivation()
ResultSet	getAutoGeneratedKeysResultset() ResultSet for rows inserted into the table (contains auto-generated keys columns only)
java.sql.Timestamp	getBeginExecutionTimestamp() Get the Timestamp for the beginning of execution.
protected long	getCurrentTimeMillis() Return the current time in milliseconds, if DEBUG and RunTimeStats is on, else return 0.
java.lang.String	getCursorName() Return the cursor name, null in this case.
java.sql.Timestamp	getEndExecutionTimestamp() Get the Timestamp for the end of execution.
long	getExecuteTime() Get the execution time in milliseconds.
ExecRow	getFirstRow() Returns the first row from the query, and returns NULL when there are no rows.
ExecRow	getLastRow() Returns the last row from the query, and returns NULL when there are no rows.
ExecRow	getNextRow() No rows to return, so throw an exception.
ExecRow	getPreviousRow() Returns the previous row from the query, and returns NULL when there are no more previous rows.
java.lang.String	getQueryPlanText(int depth) RESOLVE - This method will go away once it is overloaded in all subclasses.
ExecRow	getRelativeRow(int row) Returns the row at the relative position from the current cursor position, and returns NULL when there is no such position.
ResultDescription	getResultDescription() Returns null.
int	getRowNumber() Returns the row number of the current row.
NoPutResultSet[]	getSubqueryTrackingArray(int numSubqueries) Get the subquery ResultSet tracking array from the top ResultSet.
long	getTimeSpent(int type) Return the total amount of time spent in this ResultSet
java.sql.SQLWarning	getWarnings() Return the set of warnings generated during the execution of this result set.
boolean	isClosed() Find out if the ResultSet is closed.
long	modifiedRowCount() Returns zero.
boolean	returnsRows() Returns FALSE
ExecRow	setAfterLastRow() Sets the current position to after the last row and returns NULL because there is no current row.
ExecRow	setBeforeFirstRow() Sets the current position to before the first row and returns NULL because there is no current row.
(package private) void	setup() Set up the result set for use.
private void	setupGeneratedColumns(Activation activation, ValueRow newRow) Construct support for normalizing generated columns.

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

cleanUp, open

Field Detail

activation

final Activation activation

subqueryTrackingArray

private NoPutResultSet[] subqueryTrackingArray

statisticsTimingOn

private final boolean statisticsTimingOn

isOpen

private boolean isOpen

True if the result set has been opened, and not yet closed.

lcc

final LanguageConnectionContext lcc

beginTime

protected long beginTime

endTime

protected long endTime

beginExecutionTime

protected long beginExecutionTime

endExecutionTime

protected long endExecutionTime

firstColumn

private int firstColumn

generatedColumnPositions

private int[] generatedColumnPositions

normalizedGeneratedValues

private DataValueDescriptor[] normalizedGeneratedValues

Constructor Detail

NoRowsResultSetImpl

NoRowsResultSetImpl(Activation activation)

Method Detail

setup

void setup()
     throws StandardException

Set up the result set for use. Should always be called from open().

Throws:

StandardException - thrown on error

returnsRows

public final boolean returnsRows()

Returns FALSE

Specified by:

returnsRows in interface ResultSet

Returns:

TRUE if the statement returns rows, FALSE if not.

modifiedRowCount

public long modifiedRowCount()

Returns zero.

Specified by:

modifiedRowCount in interface ResultSet

Returns:

The number of rows affect by the statement, so far.

getResultDescription

public ResultDescription getResultDescription()

Returns null.

Specified by:

getResultDescription in interface ResultSet

Returns:

A ResultDescription describing the results of the statement.

getActivation

public final Activation getActivation()

Specified by:

getActivation in interface ResultSet

getAbsoluteRow

public final ExecRow getAbsoluteRow(int row)
                             throws StandardException

Returns the row at the absolute position from the query, and returns NULL when there is no such position. (Negative position means from the end of the result set.) Moving the cursor to an invalid position leaves the cursor positioned either before the first row (negative position) or after the last row (positive position). NOTE: An exception will be thrown on 0.

Specified by:

getAbsoluteRow in interface ResultSet

Parameters:

row - The position.

Returns:

The row at the absolute position, or NULL if no such position.

Throws:

StandardException - Thrown on failure

See Also:

Row

getRelativeRow

public final ExecRow getRelativeRow(int row)
                             throws StandardException

Returns the row at the relative position from the current cursor position, and returns NULL when there is no such position. (Negative position means toward the beginning of the result set.) Moving the cursor to an invalid position leaves the cursor positioned either before the first row (negative position) or after the last row (positive position). NOTE: 0 is valid. NOTE: An exception is thrown if the cursor is not currently positioned on a row.

Specified by:

getRelativeRow in interface ResultSet

Parameters:

row - The position.

Returns:

The row at the relative position, or NULL if no such position.

Throws:

StandardException - Thrown on failure

See Also:

Row

setBeforeFirstRow

public final ExecRow setBeforeFirstRow()
                                throws StandardException

Sets the current position to before the first row and returns NULL because there is no current row.

Specified by:

setBeforeFirstRow in interface ResultSet

Returns:

NULL.

Throws:

StandardException - Thrown on failure

See Also:

Row

getFirstRow

public final ExecRow getFirstRow()
                          throws StandardException

Returns the first row from the query, and returns NULL when there are no rows.

Specified by:

getFirstRow in interface ResultSet

Returns:

The first row, or NULL if no rows.

Throws:

StandardException - Thrown on failure

See Also:

Row

getNextRow

public final ExecRow getNextRow()
                         throws StandardException

No rows to return, so throw an exception.

Specified by:

getNextRow in interface ResultSet

Returns:

The next row, or NULL if no more rows.

Throws:

StandardException - Always throws a StandardException to indicate that this method is not intended to be used.

See Also:

Row

getPreviousRow

public final ExecRow getPreviousRow()
                             throws StandardException

Returns the previous row from the query, and returns NULL when there are no more previous rows.

Specified by:

getPreviousRow in interface ResultSet

Returns:

The previous row, or NULL if no more previous rows.

Throws:

StandardException - Thrown on failure

See Also:

Row

getLastRow

public final ExecRow getLastRow()
                         throws StandardException

Returns the last row from the query, and returns NULL when there are no rows.

Specified by:

getLastRow in interface ResultSet

Returns:

The last row, or NULL if no rows.

Throws:

StandardException - Thrown on failure

See Also:

Row

setAfterLastRow

public final ExecRow setAfterLastRow()
                              throws StandardException

Sets the current position to after the last row and returns NULL because there is no current row.

Specified by:

setAfterLastRow in interface ResultSet

Returns:

NULL.

Throws:

StandardException - Thrown on failure

See Also:

Row

clearCurrentRow

public final void clearCurrentRow()

Clear the current row. This is done after a commit on holdable result sets. This is a no-op on result set which do not provide rows.

Specified by:

clearCurrentRow in interface ResultSet

checkRowPosition

public final boolean checkRowPosition(int isType)

Determine if the cursor is before the first row in the result set.

Specified by:

checkRowPosition in interface ResultSet

Returns:

true if before the first row, false otherwise. Returns false when the result set contains no rows.

getRowNumber

public final int getRowNumber()

Returns the row number of the current row. Row numbers start from 1 and go to 'n'. Corresponds to row numbering used to position current row in the result set (as per JDBC).

Specified by:

getRowNumber in interface ResultSet

Returns:

the row number, or 0 if not on a row

close

public void close()
           throws StandardException

Dump the stat if not already done so. Close all of the open subqueries.

Specified by:

close in interface ResultSet

Throws:

StandardException - thrown on error

isClosed

public boolean isClosed()

Find out if the ResultSet is closed.

Specified by:

isClosed in interface ResultSet

Returns:

true if closed, false otherwise

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

Throws:

StandardException - on error

getExecuteTime

public long getExecuteTime()

Get the execution time in milliseconds.

Specified by:

getExecuteTime in interface ResultSet

Returns:

long The execution time in milliseconds.

getBeginExecutionTimestamp

public java.sql.Timestamp getBeginExecutionTimestamp()

Get the Timestamp for the beginning of execution.

Specified by:

getBeginExecutionTimestamp in interface ResultSet

Returns:

Timestamp The Timestamp for the beginning of execution.

getEndExecutionTimestamp

public java.sql.Timestamp getEndExecutionTimestamp()

Get the Timestamp for the end of execution.

Specified by:

getEndExecutionTimestamp in interface ResultSet

Returns:

Timestamp The Timestamp for the end of execution.

getQueryPlanText

public java.lang.String getQueryPlanText(int depth)

RESOLVE - This method will go away once it is overloaded in all subclasses. Return the query plan as a String.

Parameters:

depth - Indentation level.

Returns:

String The query plan as a String.

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).

getSubqueryTrackingArray

public final NoPutResultSet[] getSubqueryTrackingArray(int numSubqueries)

Description copied from interface: ResultSet

Get the subquery ResultSet tracking array from the top ResultSet. (Used for tracking open subqueries when closing down on an error.)

Specified by:

getSubqueryTrackingArray in interface ResultSet

Parameters:

numSubqueries - The size of the array (For allocation on demand.)

Returns:

NoPutResultSet[] Array of NoPutResultSets for subqueries.

See Also:

ResultSet.getSubqueryTrackingArray(int)

getAutoGeneratedKeysResultset

public ResultSet getAutoGeneratedKeysResultset()

Description copied from interface: ResultSet

ResultSet for rows inserted into the table (contains auto-generated keys columns only)

Specified by:

getAutoGeneratedKeysResultset in interface ResultSet

Returns:

NoPutResultSet NoPutResultSets for rows inserted into the table.

See Also:

ResultSet.getAutoGeneratedKeysResultset()

getCursorName

public java.lang.String getCursorName()

Return the cursor name, null in this case.

Specified by:

getCursorName in interface ResultSet

Returns:

A String with the name of the cursor, if any. Returns NULL if this is not a cursor statement.

See Also:

ResultSet.getCursorName()

getCurrentTimeMillis

protected final long getCurrentTimeMillis()

Return the current time in milliseconds, if DEBUG and RunTimeStats is on, else return 0. (Only pay price of system call if need to.)

Returns:

long Current time in milliseconds.

evaluateACheckConstraint

public static void evaluateACheckConstraint(GeneratedMethod checkGM,
                                            java.lang.String checkName,
                                            long heapConglom,
                                            Activation activation)
                                     throws StandardException

Run a check constraint against the current row. Raise an error if the check constraint is violated.

Parameters:

checkGM - Generated code to run the check constraint.

checkName - Name of the constraint to check.

heapConglom - Number of heap conglomerate.

activation - Class in which checkGM lives.

Throws:

StandardException - thrown on error

evaluateGenerationClauses

public void evaluateGenerationClauses(GeneratedMethod generationClauses,
                                      Activation activation,
                                      NoPutResultSet source,
                                      ExecRow newRow,
                                      boolean isUpdate)
                               throws StandardException

Compute the generation clauses on the current row in order to fill in computed columns.

Parameters:

generationClauses - the generated method which evaluates generation clauses

activation - the thread-specific instance of the generated class

source - the tuple stream driving this INSERT/UPDATE

newRow - the base row being stuffed

isUpdate - true if this is an UPDATE. false otherwise.

Throws:

StandardException

setupGeneratedColumns

private void setupGeneratedColumns(Activation activation,
                                   ValueRow newRow)
                            throws StandardException

Construct support for normalizing generated columns. This figures out which columns in the target row have generation clauses which need to be run.

Throws:

StandardException

evaluateCheckConstraints

public static void evaluateCheckConstraints(GeneratedMethod checkGM,
                                            Activation activation)
                                     throws StandardException

Run check constraints against the current row. Raise an error if a check constraint is violated.

Parameters:

checkGM - Generated code to run the check constraint.

activation - Class in which checkGM lives.

Throws:

StandardException - thrown on error

doesCommit

public boolean doesCommit()

Does this ResultSet cause a commit or rollback.

Returns:

Whether or not this ResultSet cause a commit or rollback.

addWarning

public void addWarning(java.sql.SQLWarning w)

Description copied from interface: ResultSet

Add a warning to this result set.

Specified by:

addWarning in interface ResultSet

Parameters:

w - the warning to add

getWarnings

public java.sql.SQLWarning getWarnings()

Description copied from interface: ResultSet

Return the set of warnings generated during the execution of this result set. The warnings are cleared once this call returns.

Specified by:

getWarnings in interface ResultSet