Class NoRowsResultSetImpl
- java.lang.Object
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- org.apache.derby.impl.sql.execute.NoRowsResultSetImpl
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- All Implemented Interfaces:
ResultSet
- Direct Known Subclasses:
CallStatementResultSet
,DMLWriteResultSet
,MergeResultSet
,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.
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Field Summary
Fields Modifier and Type Field Description (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
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Fields inherited from interface org.apache.derby.iapi.sql.ResultSet
CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST
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Constructor Summary
Constructors Constructor Description NoRowsResultSetImpl(Activation activation)
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description 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(boolean underMerge)
Dump the stat if not already done so.boolean
doesCommit()
Does this ResultSet cause a commit or rollback.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 ResultSetjava.sql.SQLWarning
getWarnings()
Return the set of warnings generated during the execution of this result set.boolean
isClosed()
Find out if theResultSet
is closed.long
modifiedRowCount()
Returns zero.boolean
returnsRows()
Returns FALSEExecRow
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.org.w3c.dom.Element
toXML(org.w3c.dom.Element parentNode, java.lang.String tag)
Produce an xml image of this ResultSet and its descendant ResultSets.
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Field Detail
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activation
final Activation activation
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subqueryTrackingArray
private NoPutResultSet[] subqueryTrackingArray
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statisticsTimingOn
private final boolean statisticsTimingOn
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isOpen
private boolean isOpen
True if the result set has been opened, and not yet closed.
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lcc
final LanguageConnectionContext lcc
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beginTime
protected long beginTime
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endTime
protected long endTime
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beginExecutionTime
protected long beginExecutionTime
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endExecutionTime
protected long endExecutionTime
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firstColumn
private int firstColumn
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generatedColumnPositions
private int[] generatedColumnPositions
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normalizedGeneratedValues
private DataValueDescriptor[] normalizedGeneratedValues
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Constructor Detail
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NoRowsResultSetImpl
NoRowsResultSetImpl(Activation activation)
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Method Detail
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setup
void setup() throws StandardException
Set up the result set for use. Should always be called fromopen()
.- Throws:
StandardException
- thrown on error
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returnsRows
public final boolean returnsRows()
Returns FALSE- Specified by:
returnsRows
in interfaceResultSet
- Returns:
- TRUE if the statement returns rows, FALSE if not.
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modifiedRowCount
public long modifiedRowCount()
Returns zero.- Specified by:
modifiedRowCount
in interfaceResultSet
- Returns:
- The number of rows affect by the statement, so far.
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getResultDescription
public ResultDescription getResultDescription()
Returns null.- Specified by:
getResultDescription
in interfaceResultSet
- Returns:
- A ResultDescription describing the results of the statement.
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getActivation
public final Activation getActivation()
- Specified by:
getActivation
in interfaceResultSet
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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 interfaceResultSet
- 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
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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 interfaceResultSet
- 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
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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 interfaceResultSet
- Returns:
- NULL.
- Throws:
StandardException
- Thrown on failure- See Also:
Row
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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 interfaceResultSet
- Returns:
- The first row, or NULL if no rows.
- Throws:
StandardException
- Thrown on failure- See Also:
Row
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getNextRow
public final ExecRow getNextRow() throws StandardException
No rows to return, so throw an exception.- Specified by:
getNextRow
in interfaceResultSet
- 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
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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 interfaceResultSet
- Returns:
- The previous row, or NULL if no more previous rows.
- Throws:
StandardException
- Thrown on failure- See Also:
Row
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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 interfaceResultSet
- Returns:
- The last row, or NULL if no rows.
- Throws:
StandardException
- Thrown on failure- See Also:
Row
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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 interfaceResultSet
- Returns:
- NULL.
- Throws:
StandardException
- Thrown on failure- See Also:
Row
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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 interfaceResultSet
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checkRowPosition
public final boolean checkRowPosition(int isType)
Determine if the cursor is before the first row in the result set.- Specified by:
checkRowPosition
in interfaceResultSet
- Returns:
- true if before the first row, false otherwise. Returns false when the result set contains no rows.
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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 interfaceResultSet
- Returns:
- the row number, or 0 if not on a row
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close
public void close(boolean underMerge) throws StandardException
Dump the stat if not already done so. Close all of the open subqueries.- Parameters:
underMerge
- True if this is part of an action of a MERGE statement.- Throws:
StandardException
- thrown on error
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isClosed
public boolean isClosed()
Find out if theResultSet
is closed.
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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 interfaceResultSet
- Throws:
StandardException
- on error
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getExecuteTime
public long getExecuteTime()
Get the execution time in milliseconds.- Specified by:
getExecuteTime
in interfaceResultSet
- Returns:
- long The execution time in milliseconds.
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getBeginExecutionTimestamp
public java.sql.Timestamp getBeginExecutionTimestamp()
Get the Timestamp for the beginning of execution.- Specified by:
getBeginExecutionTimestamp
in interfaceResultSet
- Returns:
- Timestamp The Timestamp for the beginning of execution.
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getEndExecutionTimestamp
public java.sql.Timestamp getEndExecutionTimestamp()
Get the Timestamp for the end of execution.- Specified by:
getEndExecutionTimestamp
in interfaceResultSet
- Returns:
- Timestamp The Timestamp for the end of execution.
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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.
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getTimeSpent
public long getTimeSpent(int type)
Return the total amount of time spent in this ResultSet- Specified by:
getTimeSpent
in interfaceResultSet
- 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).
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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 interfaceResultSet
- Parameters:
numSubqueries
- The size of the array (For allocation on demand.)- Returns:
- NoPutResultSet[] Array of NoPutResultSets for subqueries.
- See Also:
ResultSet.getSubqueryTrackingArray(int)
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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 interfaceResultSet
- Returns:
- NoPutResultSet NoPutResultSets for rows inserted into the table.
- See Also:
ResultSet.getAutoGeneratedKeysResultset()
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getCursorName
public java.lang.String getCursorName()
Return the cursor name, null in this case.- Specified by:
getCursorName
in interfaceResultSet
- Returns:
- A String with the name of the cursor, if any. Returns NULL if this is not a cursor statement.
- See Also:
ResultSet.getCursorName()
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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.
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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 clausesactivation
- the thread-specific instance of the generated classsource
- the tuple stream driving this INSERT/UPDATEnewRow
- the base row being stuffedisUpdate
- true if this is an UPDATE. false otherwise.- Throws:
StandardException
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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
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doesCommit
public boolean doesCommit()
Does this ResultSet cause a commit or rollback.- Returns:
- Whether or not this ResultSet cause a commit or rollback.
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addWarning
public void addWarning(java.sql.SQLWarning w)
Description copied from interface:ResultSet
Add a warning to this result set.- Specified by:
addWarning
in interfaceResultSet
- Parameters:
w
- the warning to add
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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 interfaceResultSet
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toXML
public org.w3c.dom.Element toXML(org.w3c.dom.Element parentNode, java.lang.String tag) throws java.lang.Exception
Description copied from interface:ResultSet
Produce an xml image of this ResultSet and its descendant ResultSets. Appends an element to the parentNode and returns the appended element.
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