Class LinkedHashSet<E>
java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractSet<E>
java.util.HashSet<E>
java.util.LinkedHashSet<E>
org.datanucleus.store.types.wrappers.LinkedHashSet<E>
org.datanucleus.store.types.wrappers.backed.LinkedHashSet<E>
- All Implemented Interfaces:
Serializable
,Cloneable
,Iterable<E>
,Collection<E>
,Set<E>
,SCO<LinkedHashSet<E>>
,SCOCollection<LinkedHashSet<E>,
,E> SCOContainer<LinkedHashSet<E>>
,BackedSCO
A mutable second-class LinkedHashSet object.
This class extends LinkedHashSet, 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:
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected boolean
protected boolean
protected boolean
protected boolean
Fields inherited from class org.datanucleus.store.types.wrappers.LinkedHashSet
delegate, ownerMmd, ownerSM
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Constructor Summary
ConstructorsConstructorDescriptionConstructor, using StateManager of the "owner" and the field name. -
Method Summary
Modifier and TypeMethodDescriptionboolean
Method to add an element to the LinkedHashSet.boolean
addAll
(Collection<? extends E> elements) Method to add a collection to the LinkedHashSet.void
clear()
Method to clear the LinkedHashSetclone()
Creates and returns a copy of this object.boolean
Accessor for whether an element is contained in this Set.boolean
Accessor for whether a collection is contained in this Set.boolean
void
getValue()
Accessor for the unwrapped value that we are wrapping.int
hashCode()
void
Method to initialise the SCO for use.void
initialise
(LinkedHashSet<E> c) Method to initialise the SCO from an existing value.void
initialise
(LinkedHashSet<E> 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 LinkedHashSet is empty.boolean
isLoaded()
Method to return if the SCO has its contents loaded.iterator()
Accessor for an iterator for the Set.void
load()
Method to effect the load of the data in the SCO.protected void
Method to load all elements from the "backing store" where appropriate.boolean
Method to remove (the first occurrence of) an element from the collectionboolean
Method to remove (the first occurrence of) an element from the collectionboolean
removeAll
(Collection elements) Method to remove all elements from the collection from the LinkedHashSet.boolean
Method to retain a Collection of elements (and remove all others).int
size()
Accessor for the size of the LinkedHashSet.stream()
Object[]
toArray()
<T> T[]
toArray
(T[] a) void
Method to unset the owner and backing store information.void
updateEmbeddedElement
(E element, int fieldNumber, Object value, boolean makeDirty) Method to update an embedded element in this collection.protected Object
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.LinkedHashSet
attachCopy, detachCopy, getFieldName, getOwner, makeDirty, setValue
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.Collection
removeIf
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Field Details
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allowNulls
protected transient boolean allowNulls -
backingStore
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useCache
protected transient boolean useCache -
isCacheLoaded
protected transient boolean isCacheLoaded -
initialising
protected transient boolean initialising
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Constructor Details
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LinkedHashSet
Constructor, using StateManager of the "owner" and the field name.- Parameters:
sm
- The owner StateManagermmd
- Metadata for the member
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Method Details
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initialise
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 classLinkedHashSet<E>
- Parameters:
newValue
- New value (to wrap)oldValue
- Old value (to use in deciding what needs deleting etc)
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initialise
Method to initialise the SCO from an existing value.- Specified by:
initialise
in interfaceSCO<E>
- Overrides:
initialise
in classLinkedHashSet<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 classLinkedHashSet<E>
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getValue
Accessor for the unwrapped value that we are wrapping. -
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 classLinkedHashSet<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 classLinkedHashSet<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. -
getBackingStore
- Specified by:
getBackingStore
in interfaceBackedSCO
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updateEmbeddedElement
Method to update an embedded element in this collection.- Specified by:
updateEmbeddedElement
in interfaceSCOCollection<LinkedHashSet<E>,
E> - Overrides:
updateEmbeddedElement
in classLinkedHashSet<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 backing store information.- Specified by:
unsetOwner
in interfaceSCO<E>
- Overrides:
unsetOwner
in classLinkedHashSet<E>
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clone
Creates and returns a copy of this object. -
contains
Description copied from class:LinkedHashSet
Accessor for whether an element is contained in this Set.- Specified by:
contains
in interfaceCollection<E>
- Specified by:
contains
in interfaceSet<E>
- Overrides:
contains
in classLinkedHashSet<E>
- Parameters:
element
- The element- Returns:
- Whether it is contained.
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containsAll
Description copied from class:LinkedHashSet
Accessor for whether a collection is contained in this Set.- Specified by:
containsAll
in interfaceCollection<E>
- Specified by:
containsAll
in interfaceSet<E>
- Overrides:
containsAll
in classLinkedHashSet<E>
- Parameters:
c
- The collection- Returns:
- Whether it is contained.
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equals
- Specified by:
equals
in interfaceCollection<E>
- Specified by:
equals
in interfaceSet<E>
- Overrides:
equals
in classLinkedHashSet<E>
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forEach
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hashCode
public int hashCode()- Specified by:
hashCode
in interfaceCollection<E>
- Specified by:
hashCode
in interfaceSet<E>
- Overrides:
hashCode
in classLinkedHashSet<E>
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isEmpty
public boolean isEmpty()Description copied from class:LinkedHashSet
Accessor for whether the LinkedHashSet is empty.- Specified by:
isEmpty
in interfaceCollection<E>
- Specified by:
isEmpty
in interfaceSet<E>
- Overrides:
isEmpty
in classLinkedHashSet<E>
- Returns:
- Whether it is empty.
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iterator
Description copied from class:LinkedHashSet
Accessor for an iterator for the Set. -
size
public int size()Description copied from class:LinkedHashSet
Accessor for the size of the LinkedHashSet.- Specified by:
size
in interfaceCollection<E>
- Specified by:
size
in interfaceSet<E>
- Overrides:
size
in classLinkedHashSet<E>
- Returns:
- The size.
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toArray
- Specified by:
toArray
in interfaceCollection<E>
- Specified by:
toArray
in interfaceSet<E>
- Overrides:
toArray
in classLinkedHashSet<E>
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toArray
public <T> T[] toArray(T[] a) - Specified by:
toArray
in interfaceCollection<E>
- Specified by:
toArray
in interfaceSet<E>
- Overrides:
toArray
in classLinkedHashSet<E>
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add
Description copied from class:LinkedHashSet
Method to add an element to the LinkedHashSet.- Specified by:
add
in interfaceCollection<E>
- Specified by:
add
in interfaceSet<E>
- Overrides:
add
in classLinkedHashSet<E>
- Parameters:
element
- The new element- Returns:
- Whether it was added ok.
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addAll
Description copied from class:LinkedHashSet
Method to add a collection to the LinkedHashSet.- Specified by:
addAll
in interfaceCollection<E>
- Specified by:
addAll
in interfaceSet<E>
- Overrides:
addAll
in classLinkedHashSet<E>
- Parameters:
elements
- The collection- Returns:
- Whether it was added ok.
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clear
public void clear()Description copied from class:LinkedHashSet
Method to clear the LinkedHashSet- Specified by:
clear
in interfaceCollection<E>
- Specified by:
clear
in interfaceSet<E>
- Overrides:
clear
in classLinkedHashSet<E>
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remove
Description copied from class:LinkedHashSet
Method to remove (the first occurrence of) an element from the collection- Specified by:
remove
in interfaceCollection<E>
- Specified by:
remove
in interfaceSet<E>
- Overrides:
remove
in classLinkedHashSet<E>
- Parameters:
element
- The Element to remove- Returns:
- Whether it was removed successfully.
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remove
Description copied from class:LinkedHashSet
Method to remove (the first occurrence of) an element from the collection- Specified by:
remove
in interfaceSCOCollection<LinkedHashSet<E>,
E> - Overrides:
remove
in classLinkedHashSet<E>
- Parameters:
element
- The Element to removeallowCascadeDelete
- Whether to cascade delete- Returns:
- Whether it was removed successfully.
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removeAll
Description copied from class:LinkedHashSet
Method to remove all elements from the collection from the LinkedHashSet.- Specified by:
removeAll
in interfaceCollection<E>
- Specified by:
removeAll
in interfaceSet<E>
- Overrides:
removeAll
in classLinkedHashSet<E>
- Parameters:
elements
- The collection of elements to remove- Returns:
- Whether it was removed ok.
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retainAll
Description copied from class:LinkedHashSet
Method to retain a Collection of elements (and remove all others).- Specified by:
retainAll
in interfaceCollection<E>
- Specified by:
retainAll
in interfaceSet<E>
- Overrides:
retainAll
in classLinkedHashSet<E>
- Parameters:
c
- The collection to retain- Returns:
- Whether they were retained successfully.
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writeReplace
Description copied from class:LinkedHashSet
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 classLinkedHashSet<E>
- Returns:
- the replaced object
- Throws:
ObjectStreamException
- if an error occurs
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spliterator
- Specified by:
spliterator
in interfaceCollection<E>
- Specified by:
spliterator
in interfaceIterable<E>
- Specified by:
spliterator
in interfaceSet<E>
- Overrides:
spliterator
in classLinkedHashSet<E>
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stream
- Specified by:
stream
in interfaceCollection<E>
- Overrides:
stream
in classLinkedHashSet<E>
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parallelStream
- Specified by:
parallelStream
in interfaceCollection<E>
- Overrides:
parallelStream
in classLinkedHashSet<E>
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