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
public class LinkedHashSet<E> extends LinkedHashSet<E> implements 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:

  • Field Details

    • allowNulls

      protected transient boolean allowNulls

    • backingStore

      protected transient SetStore<E> backingStore

    • useCache

      protected transient boolean useCache

    • isCacheLoaded

      protected transient boolean isCacheLoaded

    • initialising

      protected transient boolean initialising

  • Constructor Details

    • LinkedHashSet

      public LinkedHashSet(DNStateManager sm, AbstractMemberMetaData mmd)
      Constructor, using StateManager of the "owner" and the field name.
      Parameters:
      sm - The owner StateManager
      mmd - Metadata for the member

  • Method Details

    • initialise

      public void initialise(LinkedHashSet<E> 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<E>
      Overrides:
      initialise in class LinkedHashSet<E>
      Parameters:
      newValue - New value (to wrap)
      oldValue - Old value (to use in deciding what needs deleting etc)

    • initialise

      public void initialise(LinkedHashSet<E> c)
      Method to initialise the SCO from an existing value.
      Specified by:
      initialise in interface SCO<E>
      Overrides:
      initialise in class LinkedHashSet<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<E>
      Overrides:
      initialise in class LinkedHashSet<E>

    • getValue

      public LinkedHashSet<E> getValue()
      Accessor for the unwrapped value that we are wrapping.
      Specified by:
      getValue in interface SCO<E>
      Overrides:
      getValue in class LinkedHashSet<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<E>
      Overrides:
      load in class LinkedHashSet<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 BackedSCO
      Specified by:
      isLoaded in interface SCOContainer<E>
      Overrides:
      isLoaded in class LinkedHashSet<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<LinkedHashSet<E>, E>
      Overrides:
      updateEmbeddedElement in class LinkedHashSet<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 backing store information.
      Specified by:
      unsetOwner in interface SCO<E>
      Overrides:
      unsetOwner in class LinkedHashSet<E>

    • clone

      public Object clone()
      Creates and returns a copy of this object.
      Specified by:
      clone in interface SCO<E>
      Overrides:
      clone in class LinkedHashSet<E>
      Returns:
      The cloned object

    • contains

      public boolean contains(Object element)
      Description copied from class: LinkedHashSet
      Accessor for whether an element is contained in this Set.
      Specified by:
      contains in interface Collection<E>
      Specified by:
      contains in interface Set<E>
      Overrides:
      contains in class LinkedHashSet<E>
      Parameters:
      element - The element
      Returns:
      Whether it is contained.

    • containsAll

      public boolean containsAll(Collection c)
      Description copied from class: LinkedHashSet
      Accessor for whether a collection is contained in this Set.
      Specified by:
      containsAll in interface Collection<E>
      Specified by:
      containsAll in interface Set<E>
      Overrides:
      containsAll in class LinkedHashSet<E>
      Parameters:
      c - The collection
      Returns:
      Whether it is contained.

    • equals

      public boolean equals(Object o)
      Specified by:
      equals in interface Collection<E>
      Specified by:
      equals in interface Set<E>
      Overrides:
      equals in class LinkedHashSet<E>

    • forEach

      public void forEach(Consumer<? super E> action)
      Specified by:
      forEach in interface Iterable<E>
      Overrides:
      forEach in class LinkedHashSet<E>

    • hashCode

      public int hashCode()
      Specified by:
      hashCode in interface Collection<E>
      Specified by:
      hashCode in interface Set<E>
      Overrides:
      hashCode in class LinkedHashSet<E>

    • isEmpty

      public boolean isEmpty()
      Description copied from class: LinkedHashSet
      Accessor for whether the LinkedHashSet is empty.
      Specified by:
      isEmpty in interface Collection<E>
      Specified by:
      isEmpty in interface Set<E>
      Overrides:
      isEmpty in class LinkedHashSet<E>
      Returns:
      Whether it is empty.

    • iterator

      public Iterator<E> iterator()
      Description copied from class: LinkedHashSet
      Accessor for an iterator for the Set.
      Specified by:
      iterator in interface Collection<E>
      Specified by:
      iterator in interface Iterable<E>
      Specified by:
      iterator in interface Set<E>
      Overrides:
      iterator in class LinkedHashSet<E>
      Returns:
      The iterator

    • size

      public int size()
      Description copied from class: LinkedHashSet
      Accessor for the size of the LinkedHashSet.
      Specified by:
      size in interface Collection<E>
      Specified by:
      size in interface Set<E>
      Overrides:
      size in class LinkedHashSet<E>
      Returns:
      The size.

    • toArray

      public Object[] toArray()
      Specified by:
      toArray in interface Collection<E>
      Specified by:
      toArray in interface Set<E>
      Overrides:
      toArray in class LinkedHashSet<E>

    • toArray

      public <T> T[] toArray(T[] a)
      Specified by:
      toArray in interface Collection<E>
      Specified by:
      toArray in interface Set<E>
      Overrides:
      toArray in class LinkedHashSet<E>

    • add

      public boolean add(E element)
      Description copied from class: LinkedHashSet
      Method to add an element to the LinkedHashSet.
      Specified by:
      add in interface Collection<E>
      Specified by:
      add in interface Set<E>
      Overrides:
      add in class LinkedHashSet<E>
      Parameters:
      element - The new element
      Returns:
      Whether it was added ok.

    • addAll

      public boolean addAll(Collection<? extends E> elements)
      Description copied from class: LinkedHashSet
      Method to add a collection to the LinkedHashSet.
      Specified by:
      addAll in interface Collection<E>
      Specified by:
      addAll in interface Set<E>
      Overrides:
      addAll in class LinkedHashSet<E>
      Parameters:
      elements - The collection
      Returns:
      Whether it was added ok.

    • clear

      public void clear()
      Description copied from class: LinkedHashSet
      Method to clear the LinkedHashSet
      Specified by:
      clear in interface Collection<E>
      Specified by:
      clear in interface Set<E>
      Overrides:
      clear in class LinkedHashSet<E>

    • remove

      public boolean remove(Object element)
      Description copied from class: LinkedHashSet
      Method to remove (the first occurrence of) an element from the collection
      Specified by:
      remove in interface Collection<E>
      Specified by:
      remove in interface Set<E>
      Overrides:
      remove in class LinkedHashSet<E>
      Parameters:
      element - The Element to remove
      Returns:
      Whether it was removed successfully.

    • remove

      public boolean remove(Object element, boolean allowCascadeDelete)
      Description copied from class: LinkedHashSet
      Method to remove (the first occurrence of) an element from the collection
      Specified by:
      remove in interface SCOCollection<LinkedHashSet<E>, E>
      Overrides:
      remove in class LinkedHashSet<E>
      Parameters:
      element - The Element to remove
      allowCascadeDelete - Whether to cascade delete
      Returns:
      Whether it was removed successfully.

    • removeAll

      public boolean removeAll(Collection elements)
      Description copied from class: LinkedHashSet
      Method to remove all elements from the collection from the LinkedHashSet.
      Specified by:
      removeAll in interface Collection<E>
      Specified by:
      removeAll in interface Set<E>
      Overrides:
      removeAll in class LinkedHashSet<E>
      Parameters:
      elements - The collection of elements to remove
      Returns:
      Whether it was removed ok.

    • retainAll

      public boolean retainAll(Collection c)
      Description copied from class: LinkedHashSet
      Method to retain a Collection of elements (and remove all others).
      Specified by:
      retainAll in interface Collection<E>
      Specified by:
      retainAll in interface Set<E>
      Overrides:
      retainAll in class LinkedHashSet<E>
      Parameters:
      c - The collection to retain
      Returns:
      Whether they were retained successfully.

    • writeReplace

      protected Object writeReplace() throws ObjectStreamException
      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 class LinkedHashSet<E>
      Returns:
      the replaced object
      Throws:
      ObjectStreamException - if an error occurs

    • spliterator

      public Spliterator<E> spliterator()
      Specified by:
      spliterator in interface Collection<E>
      Specified by:
      spliterator in interface Iterable<E>
      Specified by:
      spliterator in interface Set<E>
      Overrides:
      spliterator in class LinkedHashSet<E>

    • stream

      public Stream<E> stream()
      Specified by:
      stream in interface Collection<E>
      Overrides:
      stream in class LinkedHashSet<E>

    • parallelStream

      public Stream<E> parallelStream()
      Specified by:
      parallelStream in interface Collection<E>
      Overrides:
      parallelStream in class LinkedHashSet<E>