UniqueWithDuplicateNullsIndexSortObserver (Apache Derby V10.14 Internals)

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 UUID`	`constraintId`
`private boolean`	`deferrable`
`private boolean`	`deferred`
`private BackingStoreHashtable`	`deferredDuplicates`
`private java.lang.String`	`indexOrConstraintName`
`private LanguageConnectionContext`	`lcc`
`private java.lang.String`	`tableName`

Fields inherited from class org.apache.derby.impl.sql.execute.BasicSortObserver
distinct, doClone

Constructor Summary

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

Method Summary

All Methods Instance Methods Concrete Methods
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 org.apache.derby.impl.sql.execute.BasicSortObserver
addToFreeList, getArrayClone, insertNonDuplicateKey

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - indexOrConstraintName
```
private final java.lang.String indexOrConstraintName
```
  - tableName
```
private final java.lang.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 Detail
  - UniqueWithDuplicateNullsIndexSortObserver
```
public UniqueWithDuplicateNullsIndexSortObserver(LanguageConnectionContext lcc,
                                                 UUID constraintId,
                                                 boolean doClone,
                                                 boolean deferrable,
                                                 boolean deferred,
                                                 java.lang.String indexOrConstraintName,
                                                 ExecRow execRow,
                                                 boolean reuseWrappers,
                                                 java.lang.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 Detail
  - 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

Class UniqueWithDuplicateNullsIndexSortObserver

Field Summary

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

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Field Detail

indexOrConstraintName

tableName

deferrable

deferred

lcc

constraintId

deferredDuplicates

Constructor Detail

UniqueWithDuplicateNullsIndexSortObserver

Method Detail

insertDuplicateKey

deferred

deferrable

rememberDuplicate