Class UniqueWithDuplicateNullsIndexSortObserver

java.lang.Object

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

org.apache.derby.impl.sql.execute.UniqueWithDuplicateNullsIndexSortObserver

All Implemented Interfaces:

SortObserver

public class UniqueWithDuplicateNullsIndexSortObserver
extends BasicSortObserver

UniqueWithDuplicateNullsIndexSortObserver is implementation of BasicSortObserver for eliminating non null duplicates from the backing index of unique constraint. This class is implemented to check for special case of distinct sorting where duplicate keys are allowed only if there is a null in the key part.

Field Summary

Fields

Modifier and Type	Field	Description
private final UUID	constraintId
private final boolean	deferrable
private final boolean	deferred
private BackingStoreHashtable	deferredDuplicates
private final String	indexOrConstraintName
private final LanguageConnectionContext	lcc
private final String	tableName

Fields inherited from class BasicSortObserver

distinct, doClone

Constructor Summary

Constructors

Constructor	Description
UniqueWithDuplicateNullsIndexSortObserver(LanguageConnectionContext lcc, UUID constraintId, boolean doClone, boolean deferrable, boolean deferred, String indexOrConstraintName, ExecRow execRow, boolean reuseWrappers, String tableName)	Constructs an object of UniqueWithDuplicateNullsIndexSortObserver

Method Summary

Modifier and Type	Method	Description
boolean	deferrable()	Overridden by subclasses that observe sorters with uniqueness checking.
boolean	deferred()	Overridden by subclasses that observe sorters with uniqueness checking.
DataValueDescriptor[]	insertDuplicateKey(DataValueDescriptor[] in, DataValueDescriptor[] dup)	Methods to check if the duplicate key can be inserted or not.
void	rememberDuplicate(DataValueDescriptor[] row)	Overridden by subclasses that observe sorters with uniqueness checking.

Methods inherited from class BasicSortObserver

addToFreeList, getArrayClone, insertNonDuplicateKey

Methods inherited from class Object

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

Field Details

indexOrConstraintName

private final String indexOrConstraintName

tableName

private final String tableName

deferrable

private final boolean deferrable

deferred

private final boolean deferred

lcc

private final LanguageConnectionContext lcc

constraintId

private final UUID constraintId

deferredDuplicates

private BackingStoreHashtable deferredDuplicates

Constructor Details

UniqueWithDuplicateNullsIndexSortObserver

public UniqueWithDuplicateNullsIndexSortObserver(LanguageConnectionContext lcc,
 UUID constraintId,
 boolean doClone,
 boolean deferrable,
 boolean deferred,
 String indexOrConstraintName,
 ExecRow execRow,
 boolean reuseWrappers,
 String tableName)

Constructs an object of UniqueWithDuplicateNullsIndexSortObserver

Parameters:

lcc - Language Connection context

constraintId - Id of the constraint (only used for deferrable constraints)

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

deferrable - deferrable constraint

deferred - constraint mode is deferred

indexOrConstraintName - name of index of constraint

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

reuseWrappers - Whether or not we can reuse the wrappers

tableName - name of the table

Method Details

insertDuplicateKey

public DataValueDescriptor[] insertDuplicateKey(DataValueDescriptor[] in,
 DataValueDescriptor[] dup)
                                         throws StandardException

Methods to check if the duplicate key can be inserted or not. It throws exception if the duplicates has no null part in the key.

Specified by:

insertDuplicateKey in interface SortObserver

Overrides:

insertDuplicateKey in class BasicSortObserver

Parameters:

in - new key

dup - the new key is duplicate of this key

Returns:

DVD [] if there is at least one null in the key else throws StandardException

Throws:

StandardException - is the duplicate key has all non null parts

deferred

public boolean deferred()

Description copied from interface: SortObserver

Overridden by subclasses that observe sorters with uniqueness checking.

Specified by:

deferred in interface SortObserver

Overrides:

deferred in class BasicSortObserver

Returns:

true if constraint mode of the index's constraint is effectively deferred. Any SortObserver implementations that implement uniqueness checking need to keep track of this information.

deferrable

public boolean deferrable()

Description copied from interface: SortObserver

Overridden by subclasses that observe sorters with uniqueness checking.

Specified by:

deferrable in interface SortObserver

Overrides:

deferrable in class BasicSortObserver

Returns:

true if the index's constraint is deferrable. Any SortObserver implementations that implement uniqueness checking need to keep track of this information.

rememberDuplicate

public void rememberDuplicate(DataValueDescriptor[] row)
                       throws StandardException

Description copied from interface: SortObserver

Overridden by subclasses that observe sorters with uniqueness checking. Will be called by sorters iff deferrable() and deferred() and uniqueness violation, so implementations that sometimes return true to these must implement this method to save duplicate information till commit time.

Specified by:

rememberDuplicate in interface SortObserver

Overrides:

rememberDuplicate in class BasicSortObserver

Parameters:

row - data of offending key

Throws:

StandardException - standard error policy