org.apache.derby.impl.sql.execute

Class BasicSortObserver

java.lang.Object

org.apache.derby.impl.sql.execute.BasicSortObserver

All Implemented Interfaces:

SortObserver

Direct Known Subclasses:

AggregateSortObserver, UniqueIndexSortObserver, UniqueWithDuplicateNullsIndexSortObserver

public class BasicSortObserver
extends java.lang.Object
implements SortObserver

This is the most basic sort observer. It handles distinct sorts and non-distinct sorts.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	distinct
protected boolean	doClone
private ExecRow	execRow
private boolean	reuseWrappers
private java.util.Vector	vector

Constructor Summary

Constructors

Constructor and Description
BasicSortObserver(boolean doClone, boolean distinct, ExecRow execRow, boolean reuseWrappers) Simple constructor

Method Summary

Modifier and Type	Method and Description
void	addToFreeList(DataValueDescriptor[] objectArray, int maxFreeListSize)
DataValueDescriptor[]	getArrayClone()
private DataValueDescriptor[]	getClone(DataValueDescriptor[] origArray)
DataValueDescriptor[]	insertDuplicateKey(DataValueDescriptor[] insertRow, DataValueDescriptor[] existingRow) Called prior to inserting a duplicate sort key.
DataValueDescriptor[]	insertNonDuplicateKey(DataValueDescriptor[] insertRow) Called prior to inserting a distinct sort key.

Methods inherited from class java.lang.Object

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

Field Detail

doClone

protected boolean doClone

distinct

protected boolean distinct

reuseWrappers

private boolean reuseWrappers

execRow

private ExecRow execRow

vector

private java.util.Vector vector

Constructor Detail

BasicSortObserver

public BasicSortObserver(boolean doClone,
                         boolean distinct,
                         ExecRow execRow,
                         boolean reuseWrappers)

Simple constructor

Parameters:

doClone - If true, then rows that are retained by the sorter will be cloned. This is needed if language is reusing row wrappers.

distinct - If true, toss out duplicates. Otherwise, retain them.

execRow - ExecRow to use as source of clone for store.

reuseWrappers - Whether or not we can reuse the wrappers

Method Detail

insertNonDuplicateKey

public DataValueDescriptor[] insertNonDuplicateKey(DataValueDescriptor[] insertRow)
                                            throws StandardException

Called prior to inserting a distinct sort key.

Specified by:

insertNonDuplicateKey in interface SortObserver

Parameters:

insertRow - the current row that the sorter is on the verge of retaining

Returns:

the row to be inserted by the sorter. If null, then nothing is inserted by the sorter. Distinct sorts will want to return null.

Throws:

StandardException - never thrown

insertDuplicateKey

public DataValueDescriptor[] insertDuplicateKey(DataValueDescriptor[] insertRow,
                                                DataValueDescriptor[] existingRow)
                                         throws StandardException

Called prior to inserting a duplicate sort key.

Specified by:

insertDuplicateKey in interface SortObserver

Parameters:

insertRow - the current row that the sorter is on the verge of retaining. It is a duplicate of existingRow.

existingRow - the row that is already in the the sorter which is a duplicate of insertRow

Returns:

the row to be inserted by the sorter. If null, then nothing is inserted by the sorter. Distinct sorts will want to return null.

Throws:

StandardException - never thrown

addToFreeList

public void addToFreeList(DataValueDescriptor[] objectArray,
                          int maxFreeListSize)

Specified by:

addToFreeList in interface SortObserver

getArrayClone

public DataValueDescriptor[] getArrayClone()
                                    throws StandardException

Specified by:

getArrayClone in interface SortObserver

Throws:

StandardException

getClone

private DataValueDescriptor[] getClone(DataValueDescriptor[] origArray)