org.datanucleus.sco.backed
Class TreeSet

java.lang.Object
  extended by java.util.AbstractCollection<E>
      extended by java.util.AbstractSet<E>
          extended by java.util.TreeSet
              extended by org.datanucleus.sco.backed.TreeSet
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, java.lang.Iterable, java.util.Collection, java.util.NavigableSet, java.util.Set, java.util.SortedSet, SCO, SCOCollection, SCOContainer, SCOMtoN

public class TreeSet
extends java.util.TreeSet
implements SCOCollection, SCOMtoN, java.lang.Cloneable

A mutable second-class TreeSet object. This class extends TreeSet, using that class to contain the current objects, and the backing SetStore to be the interface to the datastore. A "backing store" is not present for datastores that dont use DatastoreClass, or if the container is serialised or non-persistent.

Modes of Operation

The user can operate the list 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 container has been loaded from its "backing store" (where present) and does this as necessary. Some methods (size()) just check if everything is loaded and use the delegate if possible, otherwise going direct to the datastore.

See Also:
Serialized Form

Field Summary
protected  CollectionStore backingStore
          The "backing store"
protected  java.util.TreeSet delegate
          The internal "delegate".
protected  boolean isCacheLoaded
          Status flag whether the collection is loaded into the cache.
protected static Localiser LOCALISER
           
protected  boolean useCache
          Whether to use caching.
 
Constructor Summary
TreeSet(StateManager ownerSM, java.lang.String fieldName)
          Constructor, using the StateManager of the "owner" and the field name.
 
Method Summary
 boolean add(java.lang.Object element)
          Method to add an element to the TreeSet.
 boolean addAll(java.util.Collection elements)
          Method to add a collection to the TreeSet.
protected  void addQueuedOperation(QueuedOperation op)
          Convenience method to add a queued operation to the operations we perform at commit.
 void attachCopy(java.lang.Object value)
          Method to return an attached copy of the passed (detached) value.
 void clear()
          Method to clear the TreeSet
 java.lang.Object clone()
          Creates and returns a copy of this object.
 java.util.Comparator comparator()
          Accessor for the comparator.
 boolean contains(java.lang.Object element)
          Accessor for whether an element is contained in this Set.
 boolean containsAll(java.util.Collection c)
          Accessor for whether a collection is contained in this Set.
 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.Object first()
          Accessor for the first element in the sorted set.
 void flush()
          Method to flush the changes to the datastore when operating in queued mode.
 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.
 java.lang.Object getValue()
          Accessor for the unwrapped value that we are wrapping.
 int hashCode()
          Hashcode operator.
 java.util.SortedSet headSet(java.lang.Object toElement)
          Method to retrieve the head elements up to the specified element.
 void initialise()
          Method to initialise the SCO for use.
 void initialise(java.lang.Object o, boolean forInsert, boolean forUpdate)
          Method to initialise the SCO from an existing value.
 boolean isEmpty()
          Accessor for whether the TreeSet is empty.
 boolean isLoaded()
          Method to return if the SCO has its contents loaded.
 java.util.Iterator iterator()
          Accessor for an iterator for the Set.
 java.lang.Object last()
          Accessor for the last element in the sorted set.
 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
 boolean remove(java.lang.Object element)
          Method to remove an element from the TreeSet.
 boolean remove(java.lang.Object element, boolean allowCascadeDelete)
          Method to remove an element from the collection, and observe the flag for whether to allow cascade delete.
 boolean removeAll(java.util.Collection elements)
          Method to remove all elements from the collection from the TreeSet.
 boolean retainAll(java.util.Collection c)
          Method to retain a Collection of elements (and remove all others).
 int size()
          Accessor for the size of the TreeSet.
 java.util.SortedSet subSet(java.lang.Object fromElement, java.lang.Object toElement)
          Method to retrieve the subset of elements between the specified elements.
 java.util.SortedSet tailSet(java.lang.Object fromElement)
          Method to retrieve the set of elements after the specified element.
 java.lang.Object[] toArray()
          Method to return the list as an array.
 java.lang.Object[] toArray(java.lang.Object[] a)
          Method to return the list as an array.
 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.util.TreeSet
ceiling, descendingIterator, descendingSet, floor, headSet, higher, lower, pollFirst, pollLast, subSet, tailSet
 
Methods inherited from class java.util.AbstractCollection
toString
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 

Field Detail

LOCALISER

protected static final Localiser LOCALISER

backingStore

protected CollectionStore backingStore
The "backing store"


delegate

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


useCache

protected boolean useCache
Whether to use caching.


isCacheLoaded

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

Constructor Detail

TreeSet

public TreeSet(StateManager ownerSM,
               java.lang.String fieldName)
Constructor, using the StateManager of the "owner" and the field name.

Parameters:
ownerSM - The owner StateManager
fieldName - The name of the field of the SCO.
Method Detail

initialise

public void initialise(java.lang.Object o,
                       boolean forInsert,
                       boolean forUpdate)
Method to initialise the SCO from an existing value.

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

initialise

public void initialise()
Method to initialise the SCO for use.

Specified by:
initialise in interface SCO

getValue

public java.lang.Object getValue()
Accessor for the unwrapped value that we are wrapping.

Specified by:
getValue in interface SCO
Returns:
The unwrapped value

getElementType

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

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 SCOContainer

isLoaded

public boolean isLoaded()
Method to return if the SCO has its contents loaded. If the SCO doesn't support lazy loading will just return true.

Specified by:
isLoaded in interface SCOContainer
Returns:
Whether it is loaded

loadFromStore

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


flush

public void flush()
Method to flush the changes to the datastore when operating in queued mode. Does nothing in "direct" mode.

Specified by:
flush in interface SCOContainer

addQueuedOperation

protected void addQueuedOperation(QueuedOperation op)
Convenience method to add a queued operation to the operations we perform at commit.

Parameters:
op - The operation

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

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


detachCopy

public java.lang.Object detachCopy(FetchPlanState state)
Method to return a detached copy of the container. Recurse sthrough 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

clone

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

Specified by:
clone in interface SCO
Overrides:
clone in class java.util.TreeSet
Returns:
The cloned object

comparator

public java.util.Comparator comparator()
Accessor for the comparator.

Specified by:
comparator in interface java.util.SortedSet
Overrides:
comparator in class java.util.TreeSet
Returns:
The comparator

contains

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

Specified by:
contains in interface java.util.Collection
Specified by:
contains in interface java.util.Set
Specified by:
contains in interface SCOMtoN
Overrides:
contains in class java.util.TreeSet
Parameters:
element - The element
Returns:
Whether it is contained.

containsAll

public boolean containsAll(java.util.Collection c)
Accessor for whether a collection is contained in this Set.

Specified by:
containsAll in interface java.util.Collection
Specified by:
containsAll in interface java.util.Set
Overrides:
containsAll in class java.util.AbstractCollection
Parameters:
c - The collection
Returns:
Whether it is contained.

equals

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

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

first

public java.lang.Object first()
Accessor for the first element in the sorted set.

Specified by:
first in interface java.util.SortedSet
Overrides:
first in class java.util.TreeSet
Returns:
The first element

hashCode

public int hashCode()
Hashcode operator.

Specified by:
hashCode in interface java.util.Collection
Specified by:
hashCode in interface java.util.Set
Overrides:
hashCode in class java.util.AbstractSet
Returns:
The Hash code.

isEmpty

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

Specified by:
isEmpty in interface java.util.Collection
Specified by:
isEmpty in interface java.util.Set
Overrides:
isEmpty in class java.util.TreeSet
Returns:
Whether it is empty.

iterator

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

Specified by:
iterator in interface java.lang.Iterable
Specified by:
iterator in interface java.util.Collection
Specified by:
iterator in interface java.util.NavigableSet
Specified by:
iterator in interface java.util.Set
Overrides:
iterator in class java.util.TreeSet
Returns:
The iterator

headSet

public java.util.SortedSet headSet(java.lang.Object toElement)
Method to retrieve the head elements up to the specified element.

Specified by:
headSet in interface java.util.NavigableSet
Specified by:
headSet in interface java.util.SortedSet
Overrides:
headSet in class java.util.TreeSet
Parameters:
toElement - the element to return up to.
Returns:
The set of elements meeting the input

subSet

public java.util.SortedSet subSet(java.lang.Object fromElement,
                                  java.lang.Object toElement)
Method to retrieve the subset of elements between the specified elements.

Specified by:
subSet in interface java.util.NavigableSet
Specified by:
subSet in interface java.util.SortedSet
Overrides:
subSet in class java.util.TreeSet
Parameters:
fromElement - The start element
toElement - The end element
Returns:
The set of elements meeting the input

tailSet

public java.util.SortedSet tailSet(java.lang.Object fromElement)
Method to retrieve the set of elements after the specified element.

Specified by:
tailSet in interface java.util.NavigableSet
Specified by:
tailSet in interface java.util.SortedSet
Overrides:
tailSet in class java.util.TreeSet
Parameters:
fromElement - The start element
Returns:
The set of elements meeting the input

last

public java.lang.Object last()
Accessor for the last element in the sorted set.

Specified by:
last in interface java.util.SortedSet
Overrides:
last in class java.util.TreeSet
Returns:
The last element

size

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

Specified by:
size in interface java.util.Collection
Specified by:
size in interface java.util.Set
Overrides:
size in class java.util.TreeSet
Returns:
The size.

toArray

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

Specified by:
toArray in interface java.util.Collection
Specified by:
toArray in interface java.util.Set
Overrides:
toArray in class java.util.AbstractCollection
Returns:
The array

toArray

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

Specified by:
toArray in interface java.util.Collection
Specified by:
toArray in interface java.util.Set
Overrides:
toArray in class java.util.AbstractCollection
Parameters:
a - The runtime types of the array being defined by this param
Returns:
The array

add

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

Specified by:
add in interface java.util.Collection
Specified by:
add in interface java.util.Set
Overrides:
add in class java.util.TreeSet
Parameters:
element - The new element
Returns:
Whether it was added ok.

addAll

public boolean addAll(java.util.Collection elements)
Method to add a collection to the TreeSet.

Specified by:
addAll in interface java.util.Collection
Specified by:
addAll in interface java.util.Set
Overrides:
addAll in class java.util.TreeSet
Parameters:
elements - The collection
Returns:
Whether it was added ok.

clear

public void clear()
Method to clear the TreeSet

Specified by:
clear in interface java.util.Collection
Specified by:
clear in interface java.util.Set
Overrides:
clear in class java.util.TreeSet

remove

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

Specified by:
remove in interface java.util.Collection
Specified by:
remove in interface java.util.Set
Overrides:
remove in class java.util.TreeSet
Parameters:
element - The element
Returns:
Whether it was removed ok.

remove

public boolean remove(java.lang.Object element,
                      boolean allowCascadeDelete)
Method to remove an element from the collection, and observe the flag for whether to allow cascade delete.

Specified by:
remove in interface SCOCollection
Parameters:
element - The element
allowCascadeDelete - Whether to allow cascade delete
Returns:
Whether the element was removed

removeAll

public boolean removeAll(java.util.Collection elements)
Method to remove all elements from the collection from the TreeSet.

Specified by:
removeAll in interface java.util.Collection
Specified by:
removeAll in interface java.util.Set
Overrides:
removeAll in class java.util.AbstractSet
Parameters:
elements - The collection of elements to remove
Returns:
Whether it was removed ok.

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.Collection
Specified by:
retainAll in interface java.util.Set
Overrides:
retainAll in class java.util.AbstractCollection
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


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