Class HashSet<E>
java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractSet<E>
java.util.HashSet<E>
org.datanucleus.store.types.wrappers.HashSet<E>
org.datanucleus.store.types.wrappers.backed.HashSet<E>
- All Implemented Interfaces:
Serializable
,Cloneable
,Iterable<E>
,Collection<E>
,Set<E>
,SCO<HashSet<E>>
,SCOCollection<HashSet<E>,
,E> SCOContainer<HashSet<E>>
,BackedSCO
A mutable second-class HashSet object.
This class extends HashSet, 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
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Constructor Summary
ConstructorsConstructorDescriptionHashSet
(DNStateManager sm, AbstractMemberMetaData mmd) Constructor, using StateManager of the "owner" and the field name. -
Method Summary
Modifier and TypeMethodDescriptionboolean
Method to add an element to the set.boolean
addAll
(Collection<? extends E> elements) Method to add a collection to the set.void
clear()
Method to clear the HashSetclone()
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
(HashSet<E> c) Method to initialise the SCO from an existing value.void
initialise
(HashSet<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 HashSet 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 set.boolean
Method to retain a Collection of elements (and remove all others).int
size()
Accessor for the size of the HashSet.stream()
Object[]
toArray()
<T> T[]
toArray
(T[] a) void
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
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.HashSet
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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backingStore
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allowNulls
protected transient boolean allowNulls -
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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HashSet
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 classHashSet<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 classHashSet<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 classHashSet<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. -
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. -
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<HashSet<E>,
E> - Overrides:
updateEmbeddedElement
in classHashSet<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 classHashSet<E>
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clone
Creates and returns a copy of this object. -
contains
Description copied from class:HashSet
Accessor for whether an element is contained in this set. -
containsAll
Description copied from class:HashSet
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 classHashSet<E>
- Parameters:
c
- The collection- Returns:
- Whether it is contained.
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equals
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forEach
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hashCode
public int hashCode() -
isEmpty
public boolean isEmpty()Description copied from class:HashSet
Accessor for whether the HashSet is empty. -
iterator
Description copied from class:HashSet
Accessor for an iterator for the Set. -
size
public int size()Description copied from class:HashSet
Accessor for the size of the HashSet. -
toArray
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toArray
public <T> T[] toArray(T[] a) -
add
Description copied from class:HashSet
Method to add an element to the set. -
addAll
Description copied from class:HashSet
Method to add a collection to the set. -
clear
public void clear()Description copied from class:HashSet
Method to clear the HashSet -
remove
Description copied from class:HashSet
Method to remove (the first occurrence of) an element from the collection -
remove
Description copied from class:HashSet
Method to remove (the first occurrence of) an element from the collection -
removeAll
Description copied from class:HashSet
Method to remove all elements from the collection from the set. -
retainAll
Description copied from class:HashSet
Method to retain a Collection of elements (and remove all others). -
writeReplace
Description copied from class:HashSet
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 classHashSet<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 classHashSet<E>
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stream
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parallelStream
- Specified by:
parallelStream
in interfaceCollection<E>
- Overrides:
parallelStream
in classHashSet<E>
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