org.datanucleus.sco.backed
Class LinkedList

java.lang.Object
  extended by java.util.AbstractCollection<E>
      extended by java.util.AbstractList<E>
          extended by java.util.AbstractSequentialList<E>
              extended by java.util.LinkedList
                  extended by org.datanucleus.sco.simple.LinkedList
                      extended by org.datanucleus.sco.backed.LinkedList
All Implemented Interfaces:
java.io.Serializable, java.lang.Cloneable, java.lang.Iterable, java.util.Collection, java.util.Deque, java.util.List, java.util.Queue, SCO, SCOCollection, SCOContainer, SCOList

public class LinkedList
extends LinkedList

A mutable second-class LinkedList object. This class extends LinkedList, using that class to contain the current objects, and the backing ListStore 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  boolean allowNulls
           
protected  ListStore backingStore
           
protected  boolean isCacheLoaded
           
protected  boolean queued
           
protected  java.util.ArrayList queuedOperations
           
protected  boolean useCache
           
 
Fields inherited from class org.datanucleus.sco.simple.LinkedList
delegate, fieldName, fieldNumber, LOCALISER, owner, ownerSM
 
Fields inherited from class java.util.AbstractList
modCount
 
Constructor Summary
LinkedList(StateManager ownerSM, java.lang.String fieldName)
          Constructor, using the StateManager of the "owner" and the field name.
 
Method Summary
 void add(int index, java.lang.Object element)
          Method to add an element to a position in the LinkedList.
 boolean add(java.lang.Object element)
          Method to add an element to the LinkedList.
 boolean addAll(java.util.Collection elements)
          Method to add a Collection to the LinkedList.
 boolean addAll(int index, java.util.Collection elements)
          Method to add a Collection to a position in the LinkedList.
 void addFirst(java.lang.Object element)
          Method to add an element as first in the LinkedList.
 void addLast(java.lang.Object element)
          Method to add an element as last in the LinkedList.
protected  void addQueuedOperation(QueuedOperation op)
          Convenience method to add a queued operation to the operations we perform at commit.
 void clear()
          Method to clear the LinkedList.
 java.lang.Object clone()
          Clone operator to return a copy of this object.
 boolean contains(java.lang.Object element)
          Method to return if the list contains this element.
 boolean containsAll(java.util.Collection c)
          Accessor for whether a collection of elements are contained here.
 boolean equals(java.lang.Object o)
          Equality operator.
 void flush()
          Method to flush the changes to the datastore when operating in queued mode.
 java.lang.Object get(int index)
          Method to retrieve an element no.
 java.lang.Object getFirst()
          Method to retrieve the first element.
 java.lang.Object getLast()
          Method to retrieve the last element.
 java.lang.Object getValue()
          Accessor for the unwrapped value that we are wrapping.
 int hashCode()
          Hashcode operator.
 int indexOf(java.lang.Object element)
          Method to the position of an 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 LinkedList is empty.
 boolean isLoaded()
          Method to return if the SCO has its contents loaded.
 java.util.Iterator iterator()
          Method to retrieve an iterator for the list.
 int lastIndexOf(java.lang.Object element)
          Method to retrieve the last position of the element.
 java.util.ListIterator listIterator(int index)
          Method to retrieve a List iterator for the list from the index.
 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.
 java.lang.Object remove(int index)
          Method to remove an element from the LinkedList.
 boolean remove(java.lang.Object element)
          Method to remove an element from the LinkedList.
 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 a Collection from the LinkedList.
 java.lang.Object removeFirst()
          Method to remove the first element from the LinkedList.
 java.lang.Object removeLast()
          Method to remove the last element from the LinkedList.
 boolean retainAll(java.util.Collection c)
          Method to retain a Collection of elements (and remove all others).
 java.lang.Object set(int index, java.lang.Object element)
          Method to set the element at a position in the LinkedList.
 java.lang.Object set(int index, java.lang.Object element, boolean allowDependentField)
          JPOX wrapper addition that allows turning off of the dependent-field checks when doing the position setting.
 int size()
          Accessor for the size of the LinkedList.
 java.util.List subList(int from, int to)
          Accessor for the subList of elements between from and to of the List
 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 org.datanucleus.sco.simple.LinkedList
attachCopy, detachCopy, getFieldName, getOwner, makeDirty
 
Methods inherited from class java.util.LinkedList
descendingIterator, element, offer, offerFirst, offerLast, peek, peekFirst, peekLast, poll, pollFirst, pollLast, pop, push, remove, removeFirstOccurrence, removeLastOccurrence
 
Methods inherited from class java.util.AbstractList
listIterator, removeRange
 
Methods inherited from class java.util.AbstractCollection
toString
 
Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.List
listIterator
 

Field Detail

backingStore

protected transient ListStore backingStore

allowNulls

protected transient boolean allowNulls

useCache

protected transient boolean useCache

isCacheLoaded

protected transient boolean isCacheLoaded

queued

protected transient boolean queued

queuedOperations

protected transient java.util.ArrayList queuedOperations
Constructor Detail

LinkedList

public LinkedList(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
Overrides:
initialise in class LinkedList
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
Overrides:
initialise in class LinkedList

getValue

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

Specified by:
getValue in interface SCO
Overrides:
getValue in class LinkedList
Returns:
The unwrapped value

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
Overrides:
load in class LinkedList

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
Overrides:
isLoaded in class LinkedList
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
Overrides:
flush in class LinkedList

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
Overrides:
updateEmbeddedElement in class LinkedList
Parameters:
element - The element
fieldNumber - Number of field in the element
value - New value for this field

unsetOwner

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

Specified by:
unsetOwner in interface SCO
Overrides:
unsetOwner in class LinkedList

clone

public java.lang.Object clone()
Clone operator to return 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
Overrides:
clone in class LinkedList
Returns:
The cloned object

contains

public boolean contains(java.lang.Object element)
Method to return if the list contains this element.

Specified by:
contains in interface java.util.Collection
Specified by:
contains in interface java.util.Deque
Specified by:
contains in interface java.util.List
Overrides:
contains in class LinkedList
Parameters:
element - The element
Returns:
Whether it is contained

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

get

public java.lang.Object get(int index)
Method to retrieve an element no.

Specified by:
get in interface java.util.List
Overrides:
get in class LinkedList
Parameters:
index - The item to retrieve
Returns:
The element at that position.

getFirst

public java.lang.Object getFirst()
Method to retrieve the first element.

Specified by:
getFirst in interface java.util.Deque
Overrides:
getFirst in class LinkedList
Returns:
The first element

getLast

public java.lang.Object getLast()
Method to retrieve the last element.

Specified by:
getLast in interface java.util.Deque
Overrides:
getLast in class LinkedList
Returns:
The last element

hashCode

public int hashCode()
Hashcode operator.

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

indexOf

public int indexOf(java.lang.Object element)
Method to the position of an element.

Specified by:
indexOf in interface java.util.List
Overrides:
indexOf in class LinkedList
Parameters:
element - The element.
Returns:
The position.

isEmpty

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

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

iterator

public java.util.Iterator iterator()
Method to retrieve an iterator for the list.

Specified by:
iterator in interface java.lang.Iterable
Specified by:
iterator in interface java.util.Collection
Specified by:
iterator in interface java.util.Deque
Specified by:
iterator in interface java.util.List
Overrides:
iterator in class LinkedList
Returns:
The iterator

listIterator

public java.util.ListIterator listIterator(int index)
Method to retrieve a List iterator for the list from the index.

Specified by:
listIterator in interface java.util.List
Overrides:
listIterator in class LinkedList
Parameters:
index - The start point
Returns:
The iterator

lastIndexOf

public int lastIndexOf(java.lang.Object element)
Method to retrieve the last position of the element.

Specified by:
lastIndexOf in interface java.util.List
Overrides:
lastIndexOf in class LinkedList
Parameters:
element - The element
Returns:
The last position of this element in the List.

size

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

Specified by:
size in interface java.util.Collection
Specified by:
size in interface java.util.Deque
Specified by:
size in interface java.util.List
Overrides:
size in class LinkedList
Returns:
The size.

subList

public java.util.List subList(int from,
                              int to)
Accessor for the subList of elements between from and to of the List

Specified by:
subList in interface java.util.List
Overrides:
subList in class LinkedList
Parameters:
from - Start index (inclusive)
to - End index (exclusive)
Returns:
The subList

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.List
Overrides:
toArray in class LinkedList
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.List
Overrides:
toArray in class LinkedList
Parameters:
a - The runtime types of the array being defined by this param
Returns:
The array

add

public void add(int index,
                java.lang.Object element)
Method to add an element to a position in the LinkedList.

Specified by:
add in interface java.util.List
Overrides:
add in class LinkedList
Parameters:
index - The position
element - The new element

add

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

Specified by:
add in interface java.util.Collection
Specified by:
add in interface java.util.Deque
Specified by:
add in interface java.util.List
Specified by:
add in interface java.util.Queue
Overrides:
add in class LinkedList
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 LinkedList.

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

addAll

public boolean addAll(int index,
                      java.util.Collection elements)
Method to add a Collection to a position in the LinkedList.

Specified by:
addAll in interface java.util.List
Overrides:
addAll in class LinkedList
Parameters:
index - Position to insert the collection.
elements - The collection
Returns:
Whether it was added ok.

addFirst

public void addFirst(java.lang.Object element)
Method to add an element as first in the LinkedList.

Specified by:
addFirst in interface java.util.Deque
Overrides:
addFirst in class LinkedList
Parameters:
element - The new element

addLast

public void addLast(java.lang.Object element)
Method to add an element as last in the LinkedList.

Specified by:
addLast in interface java.util.Deque
Overrides:
addLast in class LinkedList
Parameters:
element - The new element

clear

public void clear()
Method to clear the LinkedList.

Specified by:
clear in interface java.util.Collection
Specified by:
clear in interface java.util.List
Overrides:
clear in class LinkedList

remove

public java.lang.Object remove(int index)
Method to remove an element from the LinkedList.

Specified by:
remove in interface java.util.List
Overrides:
remove in class LinkedList
Parameters:
index - The element position.
Returns:
The object that was removed

remove

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

Specified by:
remove in interface java.util.Collection
Specified by:
remove in interface java.util.Deque
Specified by:
remove in interface java.util.List
Overrides:
remove in class LinkedList
Parameters:
element - The element
Returns:
Whether the object 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
Overrides:
remove in class LinkedList
Parameters:
element - The element
allowCascadeDelete - Whether to allow cascade delete
Returns:
Whether it was removed successfully.

removeAll

public boolean removeAll(java.util.Collection elements)
Method to remove a Collection from the LinkedList.

Specified by:
removeAll in interface java.util.Collection
Specified by:
removeAll in interface java.util.List
Overrides:
removeAll in class LinkedList
Parameters:
elements - The collection
Returns:
Whether it was removed ok.

removeFirst

public java.lang.Object removeFirst()
Method to remove the first element from the LinkedList.

Specified by:
removeFirst in interface java.util.Deque
Overrides:
removeFirst in class LinkedList
Returns:
The object that was removed

removeLast

public java.lang.Object removeLast()
Method to remove the last element from the LinkedList.

Specified by:
removeLast in interface java.util.Deque
Overrides:
removeLast in class LinkedList
Returns:
The object that was removed

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.List
Overrides:
retainAll in class LinkedList
Parameters:
c - The collection to retain
Returns:
Whether they were retained successfully.

set

public java.lang.Object set(int index,
                            java.lang.Object element,
                            boolean allowDependentField)
JPOX wrapper addition that allows turning off of the dependent-field checks when doing the position setting. This means that we can prevent the deletion of the object that was previously in that position. This particular feature is used when attaching a list field and where some elements have changed positions.

Specified by:
set in interface SCOList
Overrides:
set in class LinkedList
Parameters:
index - The position
element - The new element
allowDependentField - Whether to allow dependent-field deletes
Returns:
The element previously at that position

set

public java.lang.Object set(int index,
                            java.lang.Object element)
Method to set the element at a position in the LinkedList.

Specified by:
set in interface java.util.List
Overrides:
set in class LinkedList
Parameters:
index - The position
element - The new element
Returns:
The element previously at that position

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.

Overrides:
writeReplace in class LinkedList
Returns:
the replaced object
Throws:
java.io.ObjectStreamException


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