Package org.apache.derby.impl.store.access.sort

Class SortBufferScan

java.lang.Object

org.apache.derby.impl.store.access.sort.Scan

org.apache.derby.impl.store.access.sort.SortScan

org.apache.derby.impl.store.access.sort.SortBufferScan

All Implemented Interfaces:

ScanManager, GenericScanController, GroupFetchScanController, RowCountable, ScanController, ScanInfo

public class SortBufferScan
extends SortScan

A sort scan that just reads rows out of a sorter.

Field Summary

Fields

Modifier and Type	Field	Description
protected SortBuffer	sortBuffer	The sorter we're returning rows from.

Fields inherited from class org.apache.derby.impl.store.access.sort.SortScan

current, hold, sort, tran

Fields inherited from interface org.apache.derby.iapi.store.access.ScanController

GE, GT, NA

Constructor Summary

Constructors

Constructor	Description
SortBufferScan(MergeSort sort, TransactionManager tran, SortBuffer sortBuffer, boolean hold)

Method Summary

Modifier and Type	Method	Description
void	close()	Close the scan.
boolean	closeForEndTransaction(boolean closeHeldScan)	Close the scan.
boolean	next()	Move to the next position in the scan.

Methods inherited from class org.apache.derby.impl.store.access.sort.SortScan

fetch, fetchNext, fetchWithoutQualify

Methods inherited from class org.apache.derby.impl.store.access.sort.Scan

delete, didNotQualify, doesCurrentPositionQualify, fetchLocation, fetchNextGroup, fetchNextGroup, fetchSet, getAllScanInfo, getEstimatedRowCount, getScanInfo, isCurrentPositionDeleted, isHeldAfterCommit, isKeyed, isTableLocked, newRowLocationTemplate, positionAtRowLocation, reopenScan, reopenScanByRowLocation, replace, setEstimatedRowCount

Methods inherited from class java.lang.Object

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

Field Detail

sortBuffer

protected SortBuffer sortBuffer

The sorter we're returning rows from.

Constructor Detail

SortBufferScan

SortBufferScan(MergeSort sort,
               TransactionManager tran,
               SortBuffer sortBuffer,
               boolean hold)

Method Detail

next

public boolean next()
             throws StandardException

Move to the next position in the scan.

Returns:

True if there is a next position in the scan, false if there isn't.

Throws:

StandardException - Standard exception policy.

See Also:

ScanController.next()

closeForEndTransaction

public boolean closeForEndTransaction(boolean closeHeldScan)

Close the scan.

Parameters:

closeHeldScan - If true, means to close scan even if it has been opened to be kept opened across commit. This is used to close these scans on abort.

Returns:

boolean indicating that the close has resulted in a real close of the scan. A held scan will return false if called by closeForEndTransaction(false), otherwise it will return true. A non-held scan will always return true.

close

public void close()

Close the scan.

Specified by:

close in interface GenericScanController

Overrides:

close in class SortScan

See Also:

GenericScanController.close()