CurrentOfResultSet (Apache Derby V10.14 Internals)

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.

Nested Class Summary
- Nested classes/interfaces inherited from class org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl
  BasicNoPutResultSetImpl.FieldComparator

Field Summary

Fields
Modifier and Type	Field	Description
`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.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, TEMPORARY_RESULT_SET_NUMBER

Fields inherited from class org.apache.derby.impl.sql.execute.NoPutResultSetImpl
checkNullCols, clonedExecRow, cncLen, resultSetNumber, targetResultSet

Fields inherited from interface org.apache.derby.iapi.sql.ResultSet
CURRENT_RESULTSET_ONLY, ENTIRE_RESULTSET_TREE, ISAFTERLAST, ISBEFOREFIRST, ISFIRST, ISLAST

Constructor Summary

Constructors
Constructor Description

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

Constructors
Constructor	Description
`CurrentOfResultSet(java.lang.String cursorName, Activation activation, int resultSetNumber)`

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`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.BasicNoPutResultSetImpl
addWarning, attachStatementContext, checkCancellationFlag, checkRowPosition, childrenToXML, 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, isXplainOnlyMode, markAsTopResultSet, modifiedRowCount, open, recordConstructorTime, reopenCore, requiresRelocking, returnsRows, setAfterLastRow, setBeforeFirstRow, setCompactRow, setCompatRow, toXML, toXML

Methods inherited from class org.apache.derby.impl.sql.execute.NoPutResultSetImpl
clearCurrentRow, clearOrderableCache, closeRowSource, getCursorName, getNextRowFromRowSource, getResultDescription, getValidColumns, isForUpdate, needsRowLocation, needsRowLocationForDeferredCheckConstraints, needsToClone, offendingRowLocation, positionScanAtRowLocation, printQualifiers, resultSetNumber, rowLocation, setCurrentRow, setHasDeferrableChecks, setNeedsRowLocation, setTargetResultSet, skipRow, skipScan, unpackHashValue

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, toXML

- 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()

Class CurrentOfResultSet

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl

Field Summary

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

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

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

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

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

Field Detail

next

rowLocation

cursor

target

sparseRow

cursorName

Constructor Detail

CurrentOfResultSet

Method Detail

openCore

getNextRowCore

getSparseRow

close

finish

getTimeSpent

getRowLocation

getCurrentRow

getCursor

updateRow

markRowAsDeleted