Class LinkedList<E>
- java.lang.Object
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- java.util.AbstractCollection<E>
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- java.util.AbstractList<E>
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- java.util.AbstractSequentialList<E>
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- java.util.LinkedList<E>
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- org.datanucleus.store.types.wrappers.LinkedList<E>
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- org.datanucleus.store.types.wrappers.backed.LinkedList<E>
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- All Implemented Interfaces:
Serializable
,Cloneable
,Iterable<E>
,Collection<E>
,Deque<E>
,List<E>
,Queue<E>
,SCO<LinkedList<E>>
,SCOCollection<LinkedList<E>,E>
,SCOContainer<LinkedList<E>>
,SCOList<LinkedList<E>,E>
,BackedSCO
public class LinkedList<E> extends LinkedList<E> implements BackedSCO
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
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Field Summary
Fields Modifier and Type Field Description protected boolean
allowNulls
protected ListStore<E>
backingStore
protected boolean
isCacheLoaded
protected boolean
useCache
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Fields inherited from class org.datanucleus.store.types.wrappers.LinkedList
delegate, ownerMmd, ownerOP, sorting
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Fields inherited from class java.util.AbstractList
modCount
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Constructor Summary
Constructors Constructor Description LinkedList(ObjectProvider ownerOP, AbstractMemberMetaData mmd)
Constructor, using the ObjectProvider of the "owner" and the field name.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
add(int index, E element)
Method to add an element to a position in the LinkedList.boolean
add(E element)
Method to add an element to the LinkedList.boolean
addAll(int index, Collection elements)
Method to add a Collection to a position in the LinkedList.boolean
addAll(Collection elements)
Method to add a Collection to the LinkedList.void
addFirst(E element)
Method to add an element as first in the LinkedList.void
addLast(E element)
Method to add an element as last in the LinkedList.void
clear()
Method to clear the LinkedList.Object
clone()
Clone operator to return a copy of this object.boolean
contains(Object element)
Method to return if the list contains this element.boolean
containsAll(Collection c)
Accessor for whether a collection of elements are contained here.boolean
equals(Object o)
void
forEach(java.util.function.Consumer action)
E
get(int index)
Method to retrieve an element no.Store
getBackingStore()
E
getFirst()
Method to retrieve the first element.E
getLast()
Method to retrieve the last element.LinkedList
getValue()
Accessor for the unwrapped value that we are wrapping.int
hashCode()
int
indexOf(Object element)
Method to the position of an element.void
initialise()
Method to initialise the SCO for use.void
initialise(LinkedList c)
Method to initialise the SCO from an existing value.void
initialise(LinkedList newValue, Object oldValue)
Method to initialise the SCO for use, where replacing an old value with a new value such as when calling a setter field passing in a new value.boolean
isEmpty()
Accessor for whether the LinkedList is empty.boolean
isLoaded()
Method to return if the SCO has its contents loaded.Iterator<E>
iterator()
Method to retrieve an iterator for the list.int
lastIndexOf(Object element)
Method to retrieve the last position of the element.ListIterator<E>
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.util.stream.Stream
parallelStream()
E
remove(int index)
Method to remove an element from the LinkedList.boolean
remove(Object element)
Method to remove an element from the LinkedList.boolean
remove(Object element, boolean allowCascadeDelete)
Method to remove an element from the collection, and observe the flag for whether to allow cascade delete.boolean
removeAll(Collection elements)
Method to remove a Collection from the LinkedList.E
removeFirst()
Method to remove the first element from the LinkedList.E
removeLast()
Method to remove the last element from the LinkedList.boolean
retainAll(Collection c)
Method to retain a Collection of elements (and remove all others).E
set(int index, E element)
Method to set the element at a position in the LinkedList.E
set(int index, E element, boolean allowDependentField)
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.Spliterator
spliterator()
java.util.stream.Stream
stream()
List<E>
subList(int from, int to)
Accessor for the subList of elements between from and to of the ListObject[]
toArray()
Method to return the list as an array.Object[]
toArray(Object[] a)
Method to return the list as an array.void
unsetOwner()
Method to unset the owner and field information.void
updateEmbeddedElement(E element, int fieldNumber, Object value, boolean makeDirty)
Method to update an embedded element in this collection.protected Object
writeReplace()
The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream.-
Methods inherited from class org.datanucleus.store.types.wrappers.LinkedList
attachCopy, detachCopy, getFieldName, getOwner, makeDirty, setValue, sort
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Methods inherited from class java.util.LinkedList
descendingIterator, element, offer, offerFirst, offerLast, peek, peekFirst, peekLast, poll, pollFirst, pollLast, pop, push, remove, removeFirstOccurrence, removeLastOccurrence
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Methods inherited from class java.util.AbstractList
listIterator, removeRange
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Methods inherited from class java.util.AbstractCollection
toString
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Methods inherited from class java.lang.Object
finalize, getClass, notify, notifyAll, wait, wait, wait
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Methods inherited from interface java.util.Collection
removeIf, toArray
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Methods inherited from interface java.util.List
listIterator, replaceAll
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Constructor Detail
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LinkedList
public LinkedList(ObjectProvider ownerOP, AbstractMemberMetaData mmd)
Constructor, using the ObjectProvider of the "owner" and the field name.- Parameters:
ownerOP
- The owner ObjectProvidermmd
- Metadata for the member
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Method Detail
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initialise
public void initialise(LinkedList newValue, Object oldValue)
Description copied from interface:SCO
Method to initialise the SCO for use, where replacing an old value with a new value such as when calling a setter field passing in a new value. Note that oldValue is marked as Object since for cases where the member type is Collection the newValue could be, for example, ArrayList, and the oldValue of type Collection (representing null).- Specified by:
initialise
in interfaceSCO<E>
- Overrides:
initialise
in classLinkedList<E>
- Parameters:
newValue
- New value (to wrap)oldValue
- Old value (to use in deciding what needs deleting etc)
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initialise
public void initialise(LinkedList c)
Method to initialise the SCO from an existing value.- Specified by:
initialise
in interfaceSCO<E>
- Overrides:
initialise
in classLinkedList<E>
- Parameters:
c
- The object to set from
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initialise
public void initialise()
Method to initialise the SCO for use.- Specified by:
initialise
in interfaceSCO<E>
- Overrides:
initialise
in classLinkedList<E>
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getValue
public LinkedList getValue()
Accessor for the unwrapped value that we are wrapping.
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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 interfaceSCOContainer<E>
- Overrides:
load
in classLinkedList<E>
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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 interfaceBackedSCO
- Specified by:
isLoaded
in interfaceSCOContainer<E>
- Overrides:
isLoaded
in classLinkedList<E>
- Returns:
- Whether it is loaded
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loadFromStore
protected void loadFromStore()
Method to load all elements from the "backing store" where appropriate.
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getBackingStore
public Store getBackingStore()
- Specified by:
getBackingStore
in interfaceBackedSCO
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updateEmbeddedElement
public void updateEmbeddedElement(E element, int fieldNumber, Object value, boolean makeDirty)
Method to update an embedded element in this collection.- Specified by:
updateEmbeddedElement
in interfaceSCOCollection<LinkedList<E>,E>
- Overrides:
updateEmbeddedElement
in classLinkedList<E>
- Parameters:
element
- The elementfieldNumber
- Number of field in the elementvalue
- New value for this fieldmakeDirty
- Whether to make the SCO field dirty.
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unsetOwner
public void unsetOwner()
Method to unset the owner and field information.- Specified by:
unsetOwner
in interfaceSCO<E>
- Overrides:
unsetOwner
in classLinkedList<E>
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clone
public 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 persistable objects. In contrast to Object.clone(), this method must not throw a CloneNotSupportedException.
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contains
public boolean contains(Object element)
Method to return if the list contains this element.
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containsAll
public boolean containsAll(Collection c)
Accessor for whether a collection of elements are contained here.- Specified by:
containsAll
in interfaceCollection<E>
- Specified by:
containsAll
in interfaceList<E>
- Overrides:
containsAll
in classLinkedList<E>
- Parameters:
c
- The collection of elements.- Returns:
- Whether they are contained.
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equals
public boolean equals(Object o)
- Specified by:
equals
in interfaceCollection<E>
- Specified by:
equals
in interfaceList<E>
- Overrides:
equals
in classLinkedList<E>
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forEach
public void forEach(java.util.function.Consumer action)
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get
public E get(int index)
Method to retrieve an element no.
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getFirst
public E getFirst()
Method to retrieve the first element.
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getLast
public E getLast()
Method to retrieve the last element.
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hashCode
public int hashCode()
- Specified by:
hashCode
in interfaceCollection<E>
- Specified by:
hashCode
in interfaceList<E>
- Overrides:
hashCode
in classLinkedList<E>
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indexOf
public int indexOf(Object element)
Method to the position of an element.
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isEmpty
public boolean isEmpty()
Accessor for whether the LinkedList is empty.- Specified by:
isEmpty
in interfaceCollection<E>
- Specified by:
isEmpty
in interfaceList<E>
- Overrides:
isEmpty
in classLinkedList<E>
- Returns:
- Whether it is empty.
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listIterator
public ListIterator<E> listIterator(int index)
Method to retrieve a List iterator for the list from the index.- Specified by:
listIterator
in interfaceList<E>
- Overrides:
listIterator
in classLinkedList<E>
- Parameters:
index
- The start point- Returns:
- The iterator
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lastIndexOf
public int lastIndexOf(Object element)
Method to retrieve the last position of the element.- Specified by:
lastIndexOf
in interfaceList<E>
- Overrides:
lastIndexOf
in classLinkedList<E>
- Parameters:
element
- The element- Returns:
- The last position of this element in the List.
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size
public int size()
Accessor for the size of the LinkedList.
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subList
public List<E> subList(int from, int to)
Accessor for the subList of elements between from and to of the List
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toArray
public Object[] toArray()
Method to return the list as an array.- Specified by:
toArray
in interfaceCollection<E>
- Specified by:
toArray
in interfaceList<E>
- Overrides:
toArray
in classLinkedList<E>
- Returns:
- The array
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toArray
public Object[] toArray(Object[] a)
Method to return the list as an array.- Specified by:
toArray
in interfaceCollection<E>
- Specified by:
toArray
in interfaceList<E>
- Overrides:
toArray
in classLinkedList<E>
- Parameters:
a
- The runtime types of the array being defined by this param- Returns:
- The array
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add
public void add(int index, E element)
Method to add an element to a position in the LinkedList.
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add
public boolean add(E element)
Method to add an element to the LinkedList.
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addAll
public boolean addAll(Collection elements)
Method to add a Collection to the LinkedList.
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addAll
public boolean addAll(int index, Collection elements)
Method to add a Collection to a position in the LinkedList.
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addFirst
public void addFirst(E element)
Method to add an element as first in the LinkedList.
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addLast
public void addLast(E element)
Method to add an element as last in the LinkedList.
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clear
public void clear()
Method to clear the LinkedList.- Specified by:
clear
in interfaceCollection<E>
- Specified by:
clear
in interfaceList<E>
- Overrides:
clear
in classLinkedList<E>
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remove
public E remove(int index)
Method to remove an element from the LinkedList.
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remove
public boolean remove(Object element)
Method to remove an element from the LinkedList.
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remove
public boolean remove(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 interfaceSCOCollection<LinkedList<E>,E>
- Overrides:
remove
in classLinkedList<E>
- Parameters:
element
- The elementallowCascadeDelete
- Whether to allow cascade delete- Returns:
- Whether it was removed successfully.
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removeAll
public boolean removeAll(Collection elements)
Method to remove a Collection from the LinkedList.- Specified by:
removeAll
in interfaceCollection<E>
- Specified by:
removeAll
in interfaceList<E>
- Overrides:
removeAll
in classLinkedList<E>
- Parameters:
elements
- The collection- Returns:
- Whether it was removed ok.
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removeFirst
public E removeFirst()
Method to remove the first element from the LinkedList.- Specified by:
removeFirst
in interfaceDeque<E>
- Overrides:
removeFirst
in classLinkedList<E>
- Returns:
- The object that was removed
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removeLast
public E removeLast()
Method to remove the last element from the LinkedList.- Specified by:
removeLast
in interfaceDeque<E>
- Overrides:
removeLast
in classLinkedList<E>
- Returns:
- The object that was removed
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retainAll
public boolean retainAll(Collection c)
Method to retain a Collection of elements (and remove all others).- Specified by:
retainAll
in interfaceCollection<E>
- Specified by:
retainAll
in interfaceList<E>
- Overrides:
retainAll
in classLinkedList<E>
- Parameters:
c
- The collection to retain- Returns:
- Whether they were retained successfully.
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set
public E set(int index, E element, boolean allowDependentField)
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 interfaceSCOList<LinkedList<E>,E>
- Overrides:
set
in classLinkedList<E>
- Parameters:
index
- The positionelement
- The new elementallowDependentField
- Whether to allow dependent-field deletes- Returns:
- The element previously at that position
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writeReplace
protected Object writeReplace() throws 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 classLinkedList<E>
- Returns:
- the replaced object
- Throws:
ObjectStreamException
- if an error occurs
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spliterator
public Spliterator spliterator()
- Specified by:
spliterator
in interfaceCollection<E>
- Specified by:
spliterator
in interfaceIterable<E>
- Specified by:
spliterator
in interfaceList<E>
- Overrides:
spliterator
in classLinkedList<E>
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stream
public java.util.stream.Stream stream()
- Specified by:
stream
in interfaceCollection<E>
- Overrides:
stream
in classLinkedList<E>
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parallelStream
public java.util.stream.Stream parallelStream()
- Specified by:
parallelStream
in interfaceCollection<E>
- Overrides:
parallelStream
in classLinkedList<E>
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