Class IndirectSet<E>
- java.lang.Object
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- org.eclipse.persistence.indirection.IndirectSet<E>
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- 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.)
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
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Constructor Summary
Constructors Constructor Description IndirectSet()
Construct an empty IndirectSet.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.IndirectSet(java.util.Collection<? extends E> c)
Construct an IndirectSet containing the elements of the specified collection.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method 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 UnitOfWorkboolean
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 dBvoid
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.
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Constructor Detail
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IndirectSet
public IndirectSet()
Construct an empty IndirectSet.
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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
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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 setloadFactor
- the load factor of the set- Throws:
java.lang.IllegalArgumentException
- if the specified initial capacity is negative
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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
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Method Detail
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add
public boolean add(E element)
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addAll
public boolean addAll(java.util.Collection<? extends E> c)
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clear
public void clear()
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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 interfaceIndirectCollection
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clone
public java.lang.Object clone()
- See Also:
This will result in a database query if necessary.
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contains
public boolean contains(java.lang.Object element)
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containsAll
public boolean containsAll(java.util.Collection<?> c)
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equals
public boolean equals(java.lang.Object o)
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getDelegateObject
public java.lang.Object getDelegateObject()
INTERNAL: Return the real collection object. This will force instantiation.- Specified by:
getDelegateObject
in interfaceIndirectCollection
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getValueHolder
public ValueHolderInterface getValueHolder()
INTERNAL: Return the valueHolder.- Specified by:
getValueHolder
in interfaceIndirectContainer
- Returns:
- org.eclipse.persistence.indirection.ValueHolderInterface A representation of the valueholder * which this container uses
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hasBeenRegistered
public boolean hasBeenRegistered()
INTERNAL: Return whether this IndirectSet has been registered in a UnitOfWork
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hashCode
public int hashCode()
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isEmpty
public boolean isEmpty()
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isInstantiated
public boolean isInstantiated()
Return whether the contents have been read from the database.- Specified by:
isInstantiated
in interfaceIndirectContainer
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iterator
public java.util.Iterator<E> iterator()
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remove
public boolean remove(java.lang.Object element)
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removeAll
public boolean removeAll(java.util.Collection<?> c)
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retainAll
public boolean retainAll(java.util.Collection<?> c)
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setValueHolder
public void setValueHolder(ValueHolderInterface valueHolder)
INTERNAL: Set the value holder. Note that the delegate must be cleared out.- Specified by:
setValueHolder
in interfaceIndirectContainer
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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 interfaceIndirectCollection
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size
public int size()
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toArray
public java.lang.Object[] toArray()
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toArray
public <E> E[] toArray(E[] a)
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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 classjava.lang.Object
- See Also:
AbstractCollection.toString()
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_persistence_getPropertyChangeListener
public java.beans.PropertyChangeListener _persistence_getPropertyChangeListener()
INTERNAL: Return the property change listener for change tracking.- Specified by:
_persistence_getPropertyChangeListener
in interfaceChangeTracker
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hasTrackedPropertyChangeListener
public boolean hasTrackedPropertyChangeListener()
INTERNAL: Return if the collection has a property change listener for change tracking.
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_persistence_setPropertyChangeListener
public void _persistence_setPropertyChangeListener(java.beans.PropertyChangeListener changeListener)
INTERNAL: Set the property change listener for change tracking.- Specified by:
_persistence_setPropertyChangeListener
in interfaceChangeTracker
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getTrackedAttributeName
public java.lang.String getTrackedAttributeName()
INTERNAL: Return the mapping attribute name, used to raise change events.- Specified by:
getTrackedAttributeName
in interfaceCollectionChangeTracker
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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 interfaceCollectionChangeTracker
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getRemovedElements
public java.util.Collection getRemovedElements()
INTERNAL: Return the elements that have been removed before instantiation.- Specified by:
getRemovedElements
in interfaceIndirectCollection
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getAddedElements
public java.util.Collection getAddedElements()
INTERNAL: Return the elements that have been added before instantiation.- Specified by:
getAddedElements
in interfaceIndirectCollection
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hasAddedElements
public boolean hasAddedElements()
INTERNAL: Return if any elements that have been added before instantiation.
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hasRemovedElements
public boolean hasRemovedElements()
INTERNAL: Return if any elements that have been removed before instantiation.
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hasDeferredChanges
public boolean hasDeferredChanges()
INTERNAL: Return if any elements that have been added or removed before instantiation.- Specified by:
hasDeferredChanges
in interfaceIndirectCollection
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