org.jpox.sco
Class Set

java.lang.Object
  extended byjava.util.AbstractCollection
      extended byjava.util.AbstractSet
          extended byorg.jpox.sco.Set
All Implemented Interfaces:
java.lang.Cloneable, java.util.Collection, Queryable, SCO, SCOCollection, SCOLazyLoading, SCOMtoN, java.io.Serializable, java.util.Set

public class Set
extends java.util.AbstractSet
implements SCOCollection, SCOMtoN, SCOLazyLoading, java.lang.Cloneable, Queryable, java.io.Serializable

A mutable second-class Set object, representing a field in a class, and containing elements of a particular type. Uses a "delegate" as a local store for the Set. Uses a "backing store" (SetStore) to represent the datastore. The "delegate" is updated with the "backing store" information at necessary intervals.

Modes of Operation

The user can operate the collection in 2 modes. The cached mode will use an internal cache of the elements (in the "delegate") reading them at the first opportunity and then using the cache thereafter. The non-cached mode will just go direct to the "backing store" each call.

Mutators

When the backing store is present any updates are passed direct to the datastore as well as to the "delegate". If the "backing store" isn't present the changes are made to the "delegate" only.

Accessors

When any accessor method is invoked, it typically checks whether the collection has been loaded from its backing store and does this as necessary. Some methods (size(), contains()) just check if everything is loaded and use the delegate if possible, otherwise going direct to the datastore.

Version:
$Revision: 1.30 $
See Also:
Serialized Form

Field Summary
protected  boolean allowNulls
           
protected  CollectionStore backingStore
          The "backing store" (for use when not serialised).
protected  java.util.Collection delegate
          The internal "delegate".
protected  java.lang.Class elementType
           
protected  java.lang.String fieldName
           
protected  int fieldNumber
           
protected  boolean isCacheLoaded
          Status flag whether the collection is loaded into the cache.
protected  java.lang.Object owner
           
protected  StateManager ownerSM
           
protected  boolean useCache
          Whether to use "delegate" caching.
 
Constructor Summary
Set(StateManager ownerSM, java.lang.String fieldName)
          Constructor.
Set(StateManager ownerSM, java.lang.String fieldName, boolean allowsNulls, SetStore backingStore)
          Constructor.
 
Method Summary
 boolean add(java.lang.Object element)
          Method to add an element to the Collection.
 boolean addAll(java.util.Collection c)
          Method to add a collection of elements.
 void attachCopy(java.lang.Object value)
          Method to return an attached copy of the passed (detached) value.
 void clear()
          Method to clear the Collection.
 java.lang.Object clone()
          Creates and returns a copy of this object.
 boolean contains(java.lang.Object element)
          Accessor for whether an element is contained in the Collection.
 boolean containsAll(java.util.Collection c)
          Accessor for whether a collection of elements are contained here.
 void detach(FetchPlanState state)
          Method to detach the PersistenceCapable elements of this container.
 java.lang.Object detachCopy(FetchPlanState state)
          Method to return a detached copy of the container.
 boolean equals(java.lang.Object o)
          Equality operator.
 java.lang.Class getElementType()
          Accessor for the element type.
 java.lang.String getFieldName()
          Accessor for the field name.
 java.lang.Object getOwner()
          Accessor for the owner object.
 int hashCode()
          Hashcode operator.
protected  void init(StateManager ownerSM, java.lang.String fieldName, boolean allowNulls, SetStore backingStore)
          Initialisation method.
 boolean isEmpty()
          Accessor for whether the Collection is empty.
 java.util.Iterator iterator()
          Accessor for an iterator for the Collection.
 void load()
          Method to effect the load of the data in the SCO.
protected  void loadFromStore()
          Method to load all elements from the "backing store" where appropriate.
 void makeDirty()
          Utility to mark the object as dirty
 void makeTransient(FetchPlanState state)
          Method to make transient all elements of this container.
 QueryExpression newQueryStatement()
          Method to generate a QueryStatement for the SCO.
 QueryExpression newQueryStatement(java.lang.Class candidate_class)
          Method to return a QueryStatement, using the specified candidate class.
 Query.ResultObjectFactory newResultObjectFactory(QueryExpression stmt, boolean ignoreCache, java.lang.Class resultClass, boolean useFetchPlan)
          Method to return a ResultObjectFactory for the SCO.
 boolean remove(java.lang.Object element)
          Method to remove an element from the Collection.
 boolean removeAll(java.util.Collection c)
          Method to remove a Collection of elements.
 boolean retainAll(java.util.Collection c)
          Method to retain a Collection of elements (and remove all others).
 void runReachability(java.util.Set reachables)
          Method to run reachability on this SCO.
 void setValueFrom(java.lang.Object o, boolean forUpdate)
          Mutator for setting using an object.
 int size()
          Accessor for the size of the Collection.
 java.lang.Object[] toArray()
          Method to return the Collection as an array.
 java.lang.Object[] toArray(java.lang.Object[] a)
          Method to return the Collection as an array.
 java.lang.String toString()
          Method to return the Collection as a String.
 void unsetOwner()
          Method to unset the owner and field information.
 void updateEmbeddedElement(java.lang.Object element, int fieldNumber, java.lang.Object value)
          Method to update an embedded element in this collection.
protected  java.lang.Object writeReplace()
          The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream.
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

owner

protected java.lang.Object owner

ownerSM

protected StateManager ownerSM

fieldName

protected java.lang.String fieldName

fieldNumber

protected int fieldNumber

elementType

protected java.lang.Class elementType

allowNulls

protected boolean allowNulls

backingStore

protected CollectionStore backingStore
The "backing store" (for use when not serialised).


delegate

protected java.util.Collection delegate
The internal "delegate".


useCache

protected boolean useCache
Whether to use "delegate" caching.


isCacheLoaded

protected boolean isCacheLoaded
Status flag whether the collection is loaded into the cache.

Constructor Detail

Set

public Set(StateManager ownerSM,
           java.lang.String fieldName)
Constructor.

Parameters:
ownerSM - The State Manager for this set.
fieldName - Name of the field

Set

public Set(StateManager ownerSM,
           java.lang.String fieldName,
           boolean allowsNulls,
           SetStore backingStore)
Constructor.

Parameters:
ownerSM - State Manager for the owning object
fieldName - Name of the field
allowsNulls - Whether nulls are allowed
backingStore - The backing store
Method Detail

init

protected void init(StateManager ownerSM,
                    java.lang.String fieldName,
                    boolean allowNulls,
                    SetStore backingStore)
Initialisation method.

Parameters:
ownerSM - The owner StateManager
fieldName - The name of the field of the SCO.
allowNulls - Whether nulls are allowed
backingStore - The backing store

getElementType

public java.lang.Class getElementType()
Accessor for the element type.

Specified by:
getElementType in interface SCOCollection
Returns:
the element type contained in the collection

load

public void load()
Method to effect the load of the data in the SCO. Used when the SCO supports lazy-loading to tell it to load all now.

Specified by:
load in interface SCOLazyLoading

updateEmbeddedElement

public void updateEmbeddedElement(java.lang.Object element,
                                  int fieldNumber,
                                  java.lang.Object value)
Method to update an embedded element in this collection.

Specified by:
updateEmbeddedElement in interface SCOCollection
Parameters:
element - The element
fieldNumber - Number of field in the element
value - New value for this field

setValueFrom

public void setValueFrom(java.lang.Object o,
                         boolean forUpdate)
Mutator for setting using an object.

Specified by:
setValueFrom in interface SCO
Parameters:
o - The object to set from
forUpdate - Whether to update the datastore with this value

getFieldName

public java.lang.String getFieldName()
Accessor for the field name.

Specified by:
getFieldName in interface SCO
Returns:
The field name

getOwner

public java.lang.Object getOwner()
Accessor for the owner object.

Specified by:
getOwner in interface SCO
Returns:
The owner object

unsetOwner

public void unsetOwner()
Method to unset the owner and field information.

Specified by:
unsetOwner in interface SCO

makeDirty

public void makeDirty()
Utility to mark the object as dirty


runReachability

public void runReachability(java.util.Set reachables)
Method to run reachability on this SCO.

Specified by:
runReachability in interface SCO
Parameters:
reachables - List of StateManagers reachable so far

makeTransient

public void makeTransient(FetchPlanState state)
Method to make transient all elements of this container. All elements that are PersistenceCapable will be made transient.

Specified by:
makeTransient in interface SCO
Parameters:
state - State for the fetchplan process

detach

public void detach(FetchPlanState state)
Method to detach the PersistenceCapable elements of this container.

Specified by:
detach in interface SCO
Parameters:
state - State for the detachment process

detachCopy

public java.lang.Object detachCopy(FetchPlanState state)
Method to return a detached copy of the container. Recurses through the elements so that they are likewise detached.

Specified by:
detachCopy in interface SCO
Parameters:
state - State for detachment process
Returns:
The detached container

attachCopy

public void attachCopy(java.lang.Object value)
Method to return an attached copy of the passed (detached) value. The returned attached copy is a SCO wrapper. Goes through the existing elements in the store for this owner field and removes ones no longer present, and adds new elements. All elements in the (detached) value are attached.

Specified by:
attachCopy in interface SCO
Parameters:
value - The new (collection) value

newQueryStatement

public QueryExpression newQueryStatement()
Method to generate a QueryStatement for the SCO.

Specified by:
newQueryStatement in interface Queryable
Returns:
The QueryStatement

newQueryStatement

public QueryExpression newQueryStatement(java.lang.Class candidate_class)
Method to return a QueryStatement, using the specified candidate class.

Specified by:
newQueryStatement in interface Queryable
Parameters:
candidate_class - the candidate class
Returns:
The QueryStatement
See Also:
Queryable.newQueryStatement()

newResultObjectFactory

public Query.ResultObjectFactory newResultObjectFactory(QueryExpression stmt,
                                                        boolean ignoreCache,
                                                        java.lang.Class resultClass,
                                                        boolean useFetchPlan)
Method to return a ResultObjectFactory for the SCO.

Specified by:
newResultObjectFactory in interface Queryable
Parameters:
stmt - The QueryStatement
ignoreCache - Whether to ignore the cache
resultClass - Whether to create objects of a particular class
useFetchPlan - whether to use the fetch plan to retrieve fields in the same query
Returns:
The ResultObjectFactory

clone

public java.lang.Object clone()
Creates and returns a copy of this object.

Mutable second-class Objects are required to provide a public clone method in order to allow for copying PersistenceCapable objects. In contrast to Object.clone(), this method must not throw a CloneNotSupportedException.

Specified by:
clone in interface SCO
Returns:
A clone of the object

contains

public boolean contains(java.lang.Object element)
Accessor for whether an element is contained in the Collection.

Specified by:
contains in interface SCOMtoN
Parameters:
element - The element
Returns:
Whether the element is contained here

containsAll

public boolean containsAll(java.util.Collection c)
Accessor for whether a collection of elements are contained here.

Specified by:
containsAll in interface java.util.Set
Parameters:
c - The collection of elements.
Returns:
Whether they are contained.

equals

public boolean equals(java.lang.Object o)
Equality operator.

Specified by:
equals in interface java.util.Set
Parameters:
o - The object to compare against.
Returns:
Whether this object is the same.

hashCode

public int hashCode()
Hashcode operator.

Specified by:
hashCode in interface java.util.Set
Returns:
The Hash code.

isEmpty

public boolean isEmpty()
Accessor for whether the Collection is empty.

Specified by:
isEmpty in interface Queryable
Returns:
Whether it is empty.

iterator

public java.util.Iterator iterator()
Accessor for an iterator for the Collection.

Specified by:
iterator in interface java.util.Set
Returns:
The iterator

size

public int size()
Accessor for the size of the Collection.

Specified by:
size in interface java.util.Set
Returns:
The size

toArray

public java.lang.Object[] toArray()
Method to return the Collection as an array.

Specified by:
toArray in interface java.util.Set
Returns:
The array

toArray

public java.lang.Object[] toArray(java.lang.Object[] a)
Method to return the Collection as an array.

Specified by:
toArray in interface java.util.Set
Parameters:
a - The array to write the results to
Returns:
The array

toString

public java.lang.String toString()
Method to return the Collection as a String.

Returns:
The string form

add

public boolean add(java.lang.Object element)
Method to add an element to the Collection.

Specified by:
add in interface java.util.Set
Parameters:
element - The element to add
Returns:
Whether it was added successfully.

addAll

public boolean addAll(java.util.Collection c)
Method to add a collection of elements.

Specified by:
addAll in interface java.util.Set
Parameters:
c - The collection of elements to add.
Returns:
Whether they were added successfully.

clear

public void clear()
Method to clear the Collection.

Specified by:
clear in interface java.util.Set

remove

public boolean remove(java.lang.Object element)
Method to remove an element from the Collection.

Specified by:
remove in interface java.util.Set
Parameters:
element - The Element to remove
Returns:
Whether it was removed successfully.

removeAll

public boolean removeAll(java.util.Collection c)
Method to remove a Collection of elements.

Specified by:
removeAll in interface java.util.Set
Parameters:
c - The collection to remove
Returns:
Whether they were removed successfully.

retainAll

public boolean retainAll(java.util.Collection c)
Method to retain a Collection of elements (and remove all others).

Specified by:
retainAll in interface java.util.Set
Parameters:
c - The collection to retain
Returns:
Whether they were retained successfully.

writeReplace

protected java.lang.Object writeReplace()
                                 throws java.io.ObjectStreamException
The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream. The ObjectOutputStream checks whether the class defines the writeReplace method. If the method is defined, the writeReplace method is called to allow the object to designate its replacement in the stream. The object returned should be either of the same type as the object passed in or an object that when read and resolved will result in an object of a type that is compatible with all references to the object.

Returns:
the replaced object
Throws:
java.io.ObjectStreamException

loadFromStore

protected void loadFromStore()
Method to load all elements from the "backing store" where appropriate.



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