List (DataNucleus Core 4.1.16 API)

java.lang.Object
- java.util.AbstractCollection<E>
- - java.util.AbstractList<E>
  - - org.datanucleus.store.types.wrappers.List<E>
    - - org.datanucleus.store.types.wrappers.backed.List<E>

All Implemented Interfaces:

Serializable, Cloneable, Iterable<E>, Collection<E>, List<E>, SCO<List<E>>, SCOCollection<List<E>,E>, SCOContainer<List<E>>, SCOList<List<E>,E>, BackedSCO
```
public class List<E>
extends List<E>
implements BackedSCO
```
A mutable second-class List object. This class extends AbstractList, 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

Fields
Modifier and Type Field and Description

protected boolean allowNulls

protected ListStore<E> backingStore

protected boolean isCacheLoaded

protected boolean useCache
- Fields inherited from class org.datanucleus.store.types.wrappers.List
  delegate, ownerMmd, ownerOP
- Fields inherited from class java.util.AbstractList
  modCount

Fields
Modifier and Type	Field and Description
`protected boolean`	`allowNulls`
`protected ListStore<E>`	`backingStore`
`protected boolean`	`isCacheLoaded`
`protected boolean`	`useCache`

Constructor Summary

Constructors
Constructor and Description

List(ObjectProvider ownerOP, AbstractMemberMetaData mmd)
Constructor, using the ObjectProvider of the "owner" and the field name.

Constructors
Constructor and Description
`List(ObjectProvider ownerOP, AbstractMemberMetaData mmd)` Constructor, using the ObjectProvider of the "owner" and the field name.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`boolean`	`add(E element)` Method to add an element to the List
`void`	`add(int index, E element)` Method to add an element to the List at a position.
`boolean`	`addAll(Collection elements)` Method to add a Collection to the ArrayList.
`boolean`	`addAll(int index, Collection elements)` Method to add a collection of elements.
`void`	`clear()` Method to clear the List
`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`contains(Object element)` Accessor for whether an element is contained in the List.
`boolean`	`containsAll(Collection c)` Accessor for whether a collection of elements are contained here.
`boolean`	`equals(Object o)` Equality operator.
`E`	`get(int index)` Method to retrieve an element no.
`Store`	`getBackingStore()`
`List`	`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(List c)` Method to initialise the SCO from an existing value.
`void`	`initialise(List 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 List is empty.
`boolean`	`isLoaded()` Method to return if the SCO has its contents loaded.
`Iterator<E>`	`iterator()` Accessor for an iterator for the List
`int`	`lastIndexOf(Object element)` Method to retrieve the last position of the element.
`ListIterator<E>`	`listIterator()` Method to retrieve a List iterator for the list.
`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.
`E`	`remove(int index)` Method to remove an element from the ArrayList.
`boolean`	`remove(Object element)` Method to remove an element from the List
`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 of elements from the List.
`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 ArrayList.
`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 List
`List<E>`	`subList(int from, int to)` Accessor for the subList of elements between from and to of the List
`Object[]`	`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.List
attachCopy, detachCopy, getFieldName, getOwner, makeDirty, setValue

Methods inherited from class java.util.AbstractList
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
replaceAll, sort, spliterator

Methods inherited from interface java.util.Collection
parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable
forEach

- Field Detail
  - backingStore
```
protected transient ListStore<E> backingStore
```
  - allowNulls
```
protected transient boolean allowNulls
```
  - useCache
```
protected transient boolean useCache
```
  - isCacheLoaded
```
protected transient boolean isCacheLoaded
```
- Constructor Detail
  - List
```
public List(ObjectProvider ownerOP,
            AbstractMemberMetaData mmd)
```
    Constructor, using the ObjectProvider of the "owner" and the field name.
    
    Parameters:
    
    ownerOP - The owner ObjectProvider
    
    mmd - Metadata for the member
- Method Detail
  - initialise
```
public void initialise(List 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 interface SCO<List<E>>
    
    Overrides:
    
    initialise in class List<E>
    
    Parameters:
    
    newValue - New value (to wrap)
    
    oldValue - Old value (to use in deciding what needs deleting etc)
  - initialise
```
public void initialise(List c)
```
    Method to initialise the SCO from an existing value.
    
    Specified by:
    
    initialise in interface SCO<List<E>>
    
    Overrides:
    
    initialise in class List<E>
    
    Parameters:
    
    c - The object to set from
  - initialise
```
public void initialise()
```
    Method to initialise the SCO for use.
    
    Specified by:
    
    initialise in interface SCO<List<E>>
    
    Overrides:
    
    initialise in class List<E>
  - getValue
```
public List getValue()
```
    Accessor for the unwrapped value that we are wrapping.
    
    Specified by:
    
    getValue in interface SCO<List<E>>
    
    Overrides:
    
    getValue in class List<E>
    
    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<List<E>>
    
    Overrides:
    
    load in class List<E>
  - 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<List<E>>
    
    Overrides:
    
    isLoaded in class List<E>
    
    Returns:
    
    Whether it is loaded
  - loadFromStore
```
protected void loadFromStore()
```
    Method to load all elements from the "backing store" where appropriate.
  - getBackingStore
```
public Store getBackingStore()
```
    Specified by:
    
    getBackingStore in interface BackedSCO
  - 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 interface SCOCollection<List<E>,E>
    
    Overrides:
    
    updateEmbeddedElement in class List<E>
    
    Parameters:
    
    element - The element
    
    fieldNumber - Number of field in the element
    
    value - New value for this field
    
    makeDirty - Whether to make the SCO field dirty.
  - unsetOwner
```
public void unsetOwner()
```
    Method to unset the owner and field information.
    
    Specified by:
    
    unsetOwner in interface SCO<List<E>>
    
    Overrides:
    
    unsetOwner in class List<E>
  - clone
```
public 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 persistable objects. In contrast to Object.clone(), this method must not throw a CloneNotSupportedException.
    
    Specified by:
    
    clone in interface SCO<List<E>>
    
    Overrides:
    
    clone in class List<E>
    
    Returns:
    
    The cloned object
  - contains
```
public boolean contains(Object element)
```
    Accessor for whether an element is contained in the List.
    
    Specified by:
    
    contains in interface Collection<E>
    
    Specified by:
    
    contains in interface List<E>
    
    Overrides:
    
    contains in class List<E>
    
    Parameters:
    
    element - The element
    
    Returns:
    
    Whether the element is contained here
  - containsAll
```
public boolean containsAll(Collection c)
```
    Accessor for whether a collection of elements are contained here.
    
    Specified by:
    
    containsAll in interface Collection<E>
    
    Specified by:
    
    containsAll in interface List<E>
    
    Overrides:
    
    containsAll in class List<E>
    
    Parameters:
    
    c - The collection of elements.
    
    Returns:
    
    Whether they are contained.
  - equals
```
public boolean equals(Object o)
```
    Equality operator.
    
    Specified by:
    
    equals in interface Collection<E>
    
    Specified by:
    
    equals in interface List<E>
    
    Overrides:
    
    equals in class List<E>
    
    Parameters:
    
    o - The object to compare against.
    
    Returns:
    
    Whether this object is the same.
  - get
```
public E get(int index)
```
    Method to retrieve an element no.
    
    Specified by:
    
    get in interface List<E>
    
    Overrides:
    
    get in class List<E>
    
    Parameters:
    
    index - The item to retrieve
    
    Returns:
    
    The element at that position.
  - hashCode
```
public int hashCode()
```
    Specified by:
    
    hashCode in interface Collection<E>
    
    Specified by:
    
    hashCode in interface List<E>
    
    Overrides:
    
    hashCode in class List<E>
  - indexOf
```
public int indexOf(Object element)
```
    Method to the position of an element.
    
    Specified by:
    
    indexOf in interface List<E>
    
    Overrides:
    
    indexOf in class List<E>
    
    Parameters:
    
    element - The element.
    
    Returns:
    
    The position.
  - isEmpty
```
public boolean isEmpty()
```
    Accessor for whether the List is empty.
    
    Specified by:
    
    isEmpty in interface Collection<E>
    
    Specified by:
    
    isEmpty in interface List<E>
    
    Overrides:
    
    isEmpty in class List<E>
    
    Returns:
    
    Whether it is empty.
  - lastIndexOf
```
public int lastIndexOf(Object element)
```
    Method to retrieve the last position of the element.
    
    Specified by:
    
    lastIndexOf in interface List<E>
    
    Overrides:
    
    lastIndexOf in class List<E>
    
    Parameters:
    
    element - The element
    
    Returns:
    
    The last position of this element in the List.
  - iterator
```
public Iterator<E> iterator()
```
    Accessor for an iterator for the List
    
    Specified by:
    
    iterator in interface Iterable<E>
    
    Specified by:
    
    iterator in interface Collection<E>
    
    Specified by:
    
    iterator in interface List<E>
    
    Overrides:
    
    iterator in class List<E>
    
    Returns:
    
    The iterator
  - listIterator
```
public ListIterator<E> listIterator()
```
    Method to retrieve a List iterator for the list.
    
    Specified by:
    
    listIterator in interface List<E>
    
    Overrides:
    
    listIterator in class List<E>
    
    Returns:
    
    The iterator
  - listIterator
```
public ListIterator<E> listIterator(int index)
```
    Method to retrieve a List iterator for the list from the index.
    
    Specified by:
    
    listIterator in interface List<E>
    
    Overrides:
    
    listIterator in class List<E>
    
    Parameters:
    
    index - The start point
    
    Returns:
    
    The iterator
  - size
```
public int size()
```
    Accessor for the size of the List
    
    Specified by:
    
    size in interface Collection<E>
    
    Specified by:
    
    size in interface List<E>
    
    Overrides:
    
    size in class List<E>
    
    Returns:
    
    The size
  - subList
```
public List<E> subList(int from,
                       int to)
```
    Accessor for the subList of elements between from and to of the List
    
    Specified by:
    
    subList in interface List<E>
    
    Overrides:
    
    subList in class List<E>
    
    Parameters:
    
    from - Start index (inclusive)
    
    to - End index (exclusive)
    
    Returns:
    
    The subList
  - toArray
```
public Object[] toArray()
```
    Method to return the List as an array.
    
    Specified by:
    
    toArray in interface Collection<E>
    
    Specified by:
    
    toArray in interface List<E>
    
    Overrides:
    
    toArray in class List<E>
    
    Returns:
    
    The array
  - toArray
```
public Object[] toArray(Object[] a)
```
    Method to return the List as an array.
    
    Specified by:
    
    toArray in interface Collection<E>
    
    Specified by:
    
    toArray in interface List<E>
    
    Overrides:
    
    toArray in class List<E>
    
    Parameters:
    
    a - The array to copy to
    
    Returns:
    
    The array
  - add
```
public boolean add(E element)
```
    Method to add an element to the List
    
    Specified by:
    
    add in interface Collection<E>
    
    Specified by:
    
    add in interface List<E>
    
    Overrides:
    
    add in class List<E>
    
    Parameters:
    
    element - The element to add
    
    Returns:
    
    Whether it was added successfully.
  - add
```
public void add(int index,
                E element)
```
    Method to add an element to the List at a position.
    
    Specified by:
    
    add in interface List<E>
    
    Overrides:
    
    add in class List<E>
    
    Parameters:
    
    element - The element to add
    
    index - The position
  - addAll
```
public boolean addAll(Collection elements)
```
    Method to add a Collection to the ArrayList.
    
    Specified by:
    
    addAll in interface Collection<E>
    
    Specified by:
    
    addAll in interface List<E>
    
    Overrides:
    
    addAll in class List<E>
    
    Parameters:
    
    elements - The collection
    
    Returns:
    
    Whether it was added ok.
  - addAll
```
public boolean addAll(int index,
                      Collection elements)
```
    Method to add a collection of elements.
    
    Specified by:
    
    addAll in interface List<E>
    
    Overrides:
    
    addAll in class List<E>
    
    Parameters:
    
    elements - The collection of elements to add.
    
    index - The position to add them
    
    Returns:
    
    Whether they were added successfully.
  - clear
```
public void clear()
```
    Method to clear the List
    
    Specified by:
    
    clear in interface Collection<E>
    
    Specified by:
    
    clear in interface List<E>
    
    Overrides:
    
    clear in class List<E>
  - remove
```
public boolean remove(Object element)
```
    Method to remove an element from the List
    
    Specified by:
    
    remove in interface Collection<E>
    
    Specified by:
    
    remove in interface List<E>
    
    Overrides:
    
    remove in class List<E>
    
    Parameters:
    
    element - The Element to remove
    
    Returns:
    
    Whether it was removed successfully.
  - 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 interface SCOCollection<List<E>,E>
    
    Overrides:
    
    remove in class List<E>
    
    Parameters:
    
    element - The element
    
    allowCascadeDelete - Whether to allow cascade delete
    
    Returns:
    
    Whether it was removed successfully.
  - remove
```
public E remove(int index)
```
    Method to remove an element from the ArrayList.
    
    Specified by:
    
    remove in interface List<E>
    
    Overrides:
    
    remove in class List<E>
    
    Parameters:
    
    index - The element position.
    
    Returns:
    
    The object that was removed
  - removeAll
```
public boolean removeAll(Collection elements)
```
    Method to remove a collection of elements from the List.
    
    Specified by:
    
    removeAll in interface Collection<E>
    
    Specified by:
    
    removeAll in interface List<E>
    
    Overrides:
    
    removeAll in class List<E>
    
    Parameters:
    
    elements - Collection of elements to remove
    
    Returns:
    
    Whether it was successful.
  - retainAll
```
public boolean retainAll(Collection c)
```
    Method to retain a Collection of elements (and remove all others).
    
    Specified by:
    
    retainAll in interface Collection<E>
    
    Specified by:
    
    retainAll in interface List<E>
    
    Overrides:
    
    retainAll in class List<E>
    
    Parameters:
    
    c - The collection to retain
    
    Returns:
    
    Whether they were retained successfully.
  - 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 interface SCOList<List<E>,E>
    
    Overrides:
    
    set in class List<E>
    
    Parameters:
    
    index - The position
    
    element - The new element
    
    allowDependentField - Whether to allow dependent-field deletes
    
    Returns:
    
    The element previously at that position
  - set
```
public E set(int index,
             E element)
```
    Method to set the element at a position in the ArrayList.
    
    Specified by:
    
    set in interface List<E>
    
    Overrides:
    
    set in class List<E>
    
    Parameters:
    
    index - The position
    
    element - The new element
    
    Returns:
    
    The element previously at that position
  - 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 class List<E>
    
    Returns:
    
    the replaced object
    
    Throws:
    
    ObjectStreamException - if an error occurs

Class List<E>

Modes of Operation

Mutators

Accessors

Field Summary

Fields inherited from class org.datanucleus.store.types.wrappers.List

Fields inherited from class java.util.AbstractList

Constructor Summary

Method Summary

Methods inherited from class org.datanucleus.store.types.wrappers.List

Methods inherited from class java.util.AbstractList

Methods inherited from class java.util.AbstractCollection

Methods inherited from class java.lang.Object

Methods inherited from interface java.util.List

Methods inherited from interface java.util.Collection

Methods inherited from interface java.lang.Iterable

Field Detail

backingStore

allowNulls

useCache

isCacheLoaded

Constructor Detail

List

Method Detail

initialise

initialise

initialise

getValue

load

isLoaded

loadFromStore

getBackingStore

updateEmbeddedElement

unsetOwner

clone

contains

containsAll

equals

get

hashCode

indexOf

isEmpty

lastIndexOf

iterator

listIterator

listIterator

size

subList

toArray

toArray

add

add

addAll

addAll

clear

remove

remove

remove

removeAll

retainAll

set

set

writeReplace