IndirectSet (Oracle Fusion Middleware Java API Reference for Oracle TopLink)

java.lang.Object
- org.eclipse.persistence.indirection.IndirectSet<E>

Type Parameters:

E - the type of elements maintained by this set

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.Set<E>, ChangeTracker, CollectionChangeTracker, IndirectCollection, IndirectContainer
```
public class IndirectSet<E>
extends java.lang.Object
implements CollectionChangeTracker, java.util.Set<E>, IndirectCollection, java.lang.Cloneable, java.io.Serializable
```
IndirectSet is an example implementation of the Set protocol that allows a domain class to take advantage of TopLink Indirection without having to declare its instance variable as a ValueHolderInterface.
To use an IndirectSet:
- Declare the appropriate instance variable with type Set (or Collection).
- Send the message #useTransparentCollection() to the appropriate CollectionMapping.
- Send the message #useCollectionClass(IndirectSet.class) to the same CollectionMapping. (The order of these two message sends is significant.)
TopLink will place an IndirectSet in the instance variable when the containing domain object is read from the datatabase. With the first message sent to the IndirectSet, the contents are fetched from the database and normal Set behavior is resumed.
Implementation notes:
- The Set interface is implemented by delegating nearly every message to the Set held on to by the 'delegate' instance variable. (The 'delegate' will be either a HashSet or yet another IndirectSet.)
- The IndirectContainer interface is implemented in a straightforward fashion:
  - #get- and #setValueHolder() are implemented as simple accessors for the 'valueHolder' instance variable. (Note that #setValueHolder() clears out the 'delegate' instance variable, since its contents are invalidated by the arrival of a new value holder.)
  - #isInstantiated() is simply delegated to the value holder.
- TopLink requires that the Cloneable interface be implemented. The #clone() method must clone the 'delegate'. (The implementation here uses reflection to invoke the #clone() method because it is not included in the common interface shared by IndirectSet and its base delegate class, HashSet; namely, Set.)
- TopLink requires that the Serializable interface be implemented.
- The database read is ultimately triggered when one of the "delegated" methods makes the first call to #getDelegate(), which in turn calls #buildDelegate(), which sends the message #getValue() to the value holder. The value holder performs the database read.
- For debugging purposes, #toString() will not trigger a database read. This is not required behavior.
Since:

TOPLink/Java 3.0+

Author:

Big Country

See Also:

CollectionMapping, Serialized Form

Constructor Summary

Constructors
Constructor and Description
`IndirectSet()` Construct an empty IndirectSet.
`IndirectSet(java.util.Collection<? extends E> c)` Construct an IndirectSet containing the elements of the specified collection.
`IndirectSet(int initialCapacity)` Construct an empty IndirectSet with the specified initial capacity.
`IndirectSet(int initialCapacity, float loadFactor)` Construct an empty IndirectSet with the specified initial capacity and load factor.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`java.beans.PropertyChangeListener`	`_persistence_getPropertyChangeListener()` INTERNAL: Return the property change listener for change tracking.
`void`	`_persistence_setPropertyChangeListener(java.beans.PropertyChangeListener changeListener)` INTERNAL: Set the property change listener for change tracking.
`boolean`	`add(E element)`
`boolean`	`addAll(java.util.Collection<? extends E> c)`
`void`	`clear()`
`void`	`clearDeferredChanges()` INTERNAL: clear any changes that have been deferred to instantiation.
`java.lang.Object`	`clone()`
`boolean`	`contains(java.lang.Object element)`
`boolean`	`containsAll(java.util.Collection<?> c)`
`boolean`	`equals(java.lang.Object o)`
`java.util.Collection`	`getAddedElements()` INTERNAL: Return the elements that have been added before instantiation.
`java.lang.Object`	`getDelegateObject()` INTERNAL: Return the real collection object.
`java.util.Collection`	`getRemovedElements()` INTERNAL: Return the elements that have been removed before instantiation.
`java.lang.String`	`getTrackedAttributeName()` INTERNAL: Return the mapping attribute name, used to raise change events.
`ValueHolderInterface`	`getValueHolder()` INTERNAL: Return the valueHolder.
`boolean`	`hasAddedElements()` INTERNAL: Return if any elements that have been added before instantiation.
`boolean`	`hasBeenRegistered()` INTERNAL: Return whether this IndirectSet has been registered in a UnitOfWork
`boolean`	`hasDeferredChanges()` INTERNAL: Return if any elements that have been added or removed before instantiation.
`int`	`hashCode()`
`boolean`	`hasRemovedElements()` INTERNAL: Return if any elements that have been removed before instantiation.
`boolean`	`hasTrackedPropertyChangeListener()` INTERNAL: Return if the collection has a property change listener for change tracking.
`boolean`	`isEmpty()`
`boolean`	`isInstantiated()` Return whether the contents have been read from the database.
`java.util.Iterator<E>`	`iterator()`
`boolean`	`remove(java.lang.Object element)`
`boolean`	`removeAll(java.util.Collection<?> c)`
`boolean`	`retainAll(java.util.Collection<?> c)`
`void`	`setTrackedAttributeName(java.lang.String attributeName)` INTERNAL: Set the mapping attribute name, used to raise change events.
`void`	`setUseLazyInstantiation(boolean useLazyInstantiation)` INTERNAL Set whether this collection should attempt do deal with adds and removes without retrieving the collection from the dB
`void`	`setValueHolder(ValueHolderInterface valueHolder)` INTERNAL: Set the value holder.
`int`	`size()`
`java.lang.Object[]`	`toArray()`
`<E> E[]`	`toArray(E[] a)`
`java.lang.String`	`toString()` Use the delegate's #toString(); but wrap it with braces to indicate there is a bit of indirection.

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.Set
spliterator

Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable
forEach

- Constructor Detail
  - IndirectSet
```
public IndirectSet()
```
    Construct an empty IndirectSet.
  - IndirectSet
```
public IndirectSet(int initialCapacity)
```
    Construct an empty IndirectSet with the specified initial capacity.
    
    Parameters:
    
    initialCapacity - the initial capacity of the set
    
    Throws:
    
    java.lang.IllegalArgumentException - if the specified initial capacity is negative
  - IndirectSet
```
public IndirectSet(int initialCapacity,
                   float loadFactor)
```
    Construct an empty IndirectSet with the specified initial capacity and load factor.
    
    Parameters:
    
    initialCapacity - the initial capacity of the set
    
    loadFactor - the load factor of the set
    
    Throws:
    
    java.lang.IllegalArgumentException - if the specified initial capacity is negative
  - IndirectSet
```
public IndirectSet(java.util.Collection<? extends E> c)
```
    Construct an IndirectSet containing the elements of the specified collection.
    
    Parameters:
    
    c - the initial elements of the set
- Method Detail
  - add
```
public boolean add(E element)
```
    Specified by:
    
    add in interface java.util.Collection<E>
    
    Specified by:
    
    add in interface java.util.Set<E>
    
    See Also:
    
    Set.add(java.lang.Object)
  - addAll
```
public boolean addAll(java.util.Collection<? extends E> c)
```
    Specified by:
    
    addAll in interface java.util.Collection<E>
    
    Specified by:
    
    addAll in interface java.util.Set<E>
    
    See Also:
    
    Set.addAll(java.util.Collection)
  - clear
```
public void clear()
```
    Specified by:
    
    clear in interface java.util.Collection<E>
    
    Specified by:
    
    clear in interface java.util.Set<E>
    
    See Also:
    
    Set.clear()
  - clearDeferredChanges
```
public void clearDeferredChanges()
```
    INTERNAL: clear any changes that have been deferred to instantiation. Indirect collections with change tracking avoid instantiation on add/remove.
    
    Specified by:
    
    clearDeferredChanges in interface IndirectCollection
  - clone
```
public java.lang.Object clone()
```
    Overrides:
    
    clone in class java.lang.Object
    
    See Also:
    
    This will result in a database query if necessary.
  - contains
```
public boolean contains(java.lang.Object element)
```
    Specified by:
    
    contains in interface java.util.Collection<E>
    
    Specified by:
    
    contains in interface java.util.Set<E>
    
    See Also:
    
    Set.contains(java.lang.Object)
  - containsAll
```
public boolean containsAll(java.util.Collection<?> c)
```
    Specified by:
    
    containsAll in interface java.util.Collection<E>
    
    Specified by:
    
    containsAll in interface java.util.Set<E>
    
    See Also:
    
    Set.containsAll(java.util.Collection)
  - equals
```
public boolean equals(java.lang.Object o)
```
    Specified by:
    
    equals in interface java.util.Collection<E>
    
    Specified by:
    
    equals in interface java.util.Set<E>
    
    Overrides:
    
    equals in class java.lang.Object
    
    See Also:
    
    Set.equals(java.lang.Object)
  - getDelegateObject
```
public java.lang.Object getDelegateObject()
```
    INTERNAL: Return the real collection object. This will force instantiation.
    
    Specified by:
    
    getDelegateObject in interface IndirectCollection
  - getValueHolder
```
public ValueHolderInterface getValueHolder()
```
    INTERNAL: Return the valueHolder.
    
    Specified by:
    
    getValueHolder in interface IndirectContainer
    
    Returns:
    
    org.eclipse.persistence.indirection.ValueHolderInterface A representation of the valueholder * which this container uses
  - hasBeenRegistered
```
public boolean hasBeenRegistered()
```
    INTERNAL: Return whether this IndirectSet has been registered in a UnitOfWork
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in interface java.util.Collection<E>
    
    Specified by:
    
    hashCode in interface java.util.Set<E>
    
    Overrides:
    
    hashCode in class java.lang.Object
    
    See Also:
    
    Set.hashCode()
  - isEmpty
```
public boolean isEmpty()
```
    Specified by:
    
    isEmpty in interface java.util.Collection<E>
    
    Specified by:
    
    isEmpty in interface java.util.Set<E>
    
    See Also:
    
    Set.isEmpty()
  - isInstantiated
```
public boolean isInstantiated()
```
    Return whether the contents have been read from the database.
    
    Specified by:
    
    isInstantiated in interface IndirectContainer
  - iterator
```
public java.util.Iterator<E> iterator()
```
    Specified by:
    
    iterator in interface java.lang.Iterable<E>
    
    Specified by:
    
    iterator in interface java.util.Collection<E>
    
    Specified by:
    
    iterator in interface java.util.Set<E>
    
    See Also:
    
    Set.iterator()
  - remove
```
public boolean remove(java.lang.Object element)
```
    Specified by:
    
    remove in interface java.util.Collection<E>
    
    Specified by:
    
    remove in interface java.util.Set<E>
    
    See Also:
    
    Set.remove(java.lang.Object)
  - removeAll
```
public boolean removeAll(java.util.Collection<?> c)
```
    Specified by:
    
    removeAll in interface java.util.Collection<E>
    
    Specified by:
    
    removeAll in interface java.util.Set<E>
    
    See Also:
    
    Set.removeAll(java.util.Collection)
  - retainAll
```
public boolean retainAll(java.util.Collection<?> c)
```
    Specified by:
    
    retainAll in interface java.util.Collection<E>
    
    Specified by:
    
    retainAll in interface java.util.Set<E>
    
    See Also:
    
    Set.retainAll(java.util.Collection)
  - setValueHolder
```
public void setValueHolder(ValueHolderInterface valueHolder)
```
    INTERNAL: Set the value holder. Note that the delegate must be cleared out.
    
    Specified by:
    
    setValueHolder in interface IndirectContainer
  - setUseLazyInstantiation
```
public void setUseLazyInstantiation(boolean useLazyInstantiation)
```
    INTERNAL Set whether this collection should attempt do deal with adds and removes without retrieving the collection from the dB
    
    Specified by:
    
    setUseLazyInstantiation in interface IndirectCollection
  - size
```
public int size()
```
    Specified by:
    
    size in interface java.util.Collection<E>
    
    Specified by:
    
    size in interface java.util.Set<E>
    
    See Also:
    
    Set.size()
  - toArray
```
public java.lang.Object[] toArray()
```
    Specified by:
    
    toArray in interface java.util.Collection<E>
    
    Specified by:
    
    toArray in interface java.util.Set<E>
    
    See Also:
    
    Set.toArray()
  - toArray
```
public <E> E[] toArray(E[] a)
```
    Specified by:
    
    toArray in interface java.util.Collection<E>
    
    Specified by:
    
    toArray in interface java.util.Set<E>
    
    See Also:
    
    Set.toArray(java.lang.Object[])
  - toString
```
public java.lang.String toString()
```
    Use the delegate's #toString(); but wrap it with braces to indicate there is a bit of indirection. Don't allow this method to trigger a database read.
    
    Overrides:
    
    toString in class java.lang.Object
    
    See Also:
    
    AbstractCollection.toString()
  - _persistence_getPropertyChangeListener
```
public java.beans.PropertyChangeListener _persistence_getPropertyChangeListener()
```
    INTERNAL: Return the property change listener for change tracking.
    
    Specified by:
    
    _persistence_getPropertyChangeListener in interface ChangeTracker
  - hasTrackedPropertyChangeListener
```
public boolean hasTrackedPropertyChangeListener()
```
    INTERNAL: Return if the collection has a property change listener for change tracking.
  - _persistence_setPropertyChangeListener
```
public void _persistence_setPropertyChangeListener(java.beans.PropertyChangeListener changeListener)
```
    INTERNAL: Set the property change listener for change tracking.
    
    Specified by:
    
    _persistence_setPropertyChangeListener in interface ChangeTracker
  - getTrackedAttributeName
```
public java.lang.String getTrackedAttributeName()
```
    INTERNAL: Return the mapping attribute name, used to raise change events.
    
    Specified by:
    
    getTrackedAttributeName in interface CollectionChangeTracker
  - setTrackedAttributeName
```
public void setTrackedAttributeName(java.lang.String attributeName)
```
    INTERNAL: Set the mapping attribute name, used to raise change events. This is required if the change listener is set.
    
    Specified by:
    
    setTrackedAttributeName in interface CollectionChangeTracker
  - getRemovedElements
```
public java.util.Collection getRemovedElements()
```
    INTERNAL: Return the elements that have been removed before instantiation.
    
    Specified by:
    
    getRemovedElements in interface IndirectCollection
  - getAddedElements
```
public java.util.Collection getAddedElements()
```
    INTERNAL: Return the elements that have been added before instantiation.
    
    Specified by:
    
    getAddedElements in interface IndirectCollection
  - hasAddedElements
```
public boolean hasAddedElements()
```
    INTERNAL: Return if any elements that have been added before instantiation.
  - hasRemovedElements
```
public boolean hasRemovedElements()
```
    INTERNAL: Return if any elements that have been removed before instantiation.
  - hasDeferredChanges
```
public boolean hasDeferredChanges()
```
    INTERNAL: Return if any elements that have been added or removed before instantiation.
    
    Specified by:
    
    hasDeferredChanges in interface IndirectCollection

Class IndirectSet<E>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.Set

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Constructor Detail

IndirectSet

IndirectSet

IndirectSet

IndirectSet

Method Detail

add

addAll

clear

clearDeferredChanges

clone

contains

containsAll

equals

getDelegateObject

getValueHolder

hasBeenRegistered

hashCode

isEmpty

isInstantiated

iterator

remove

removeAll

retainAll

setValueHolder

setUseLazyInstantiation

size

toArray

toArray

toString

_persistence_getPropertyChangeListener

hasTrackedPropertyChangeListener

_persistence_setPropertyChangeListener

getTrackedAttributeName

setTrackedAttributeName

getRemovedElements

getAddedElements

hasAddedElements

hasRemovedElements

hasDeferredChanges