Package org.datanucleus.store.types.wrappers.backed

Class LinkedHashSet<E>

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Cloneable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.Set<E>, SCO<java.util.LinkedHashSet<E>>, SCOCollection<java.util.LinkedHashSet<E>,​E>, SCOContainer<java.util.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:
    Serialized Form

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      boolean add​(E element)
      Method to add an element to the LinkedHashSet.
      boolean addAll​(java.util.Collection<? extends E> elements)
      Method to add a collection to the LinkedHashSet.
      void clear()
      Method to clear the LinkedHashSet
      java.lang.Object clone()
      Creates and returns a copy of this object.
      boolean contains​(java.lang.Object element)
      Accessor for whether an element is contained in this Set.
      boolean containsAll​(java.util.Collection c)
      Accessor for whether a collection is contained in this Set.
      boolean equals​(java.lang.Object o)  
      void forEach​(java.util.function.Consumer<? super E> action)  
      Store getBackingStore()  
      java.util.LinkedHashSet<E> getValue()
      Accessor for the unwrapped value that we are wrapping.
      int hashCode()  
      void initialise()
      Method to initialise the SCO for use.
      void initialise​(java.util.LinkedHashSet<E> c)
      Method to initialise the SCO from an existing value.
      void initialise​(java.util.LinkedHashSet<E> newValue, java.lang.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.
      java.util.Iterator<E> iterator()
      Accessor for an iterator for the Set.
      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<E> parallelStream()  
      boolean remove​(java.lang.Object element)
      Method to remove (the first occurrence of) an element from the collection
      boolean remove​(java.lang.Object element, boolean allowCascadeDelete)
      Method to remove (the first occurrence of) an element from the collection
      boolean removeAll​(java.util.Collection elements)
      Method to remove all elements from the collection from the LinkedHashSet.
      boolean retainAll​(java.util.Collection c)
      Method to retain a Collection of elements (and remove all others).
      int size()
      Accessor for the size of the LinkedHashSet.
      java.util.Spliterator<E> spliterator()  
      java.util.stream.Stream<E> stream()  
      java.lang.Object[] toArray()  
      <T> T[] toArray​(T[] a)  
      void unsetOwner()
      Method to unset the owner and backing store information.
      void updateEmbeddedElement​(E element, int fieldNumber, java.lang.Object value, boolean makeDirty)
      Method to update an embedded element in this collection.
      protected java.lang.Object writeReplace()
      The writeReplace method is called when ObjectOutputStream is preparing to write the object to the stream.

      • 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

    • Field Detail

      • 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 Detail

      • 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 Detail

      • initialise

        public void initialise​(java.util.LinkedHashSet<E> newValue,
                       java.lang.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​(java.util.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

      • getValue

        public java.util.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.

      • updateEmbeddedElement

        public void updateEmbeddedElement​(E element,
                                  int fieldNumber,
                                  java.lang.Object value,
                                  boolean makeDirty)
        Method to update an embedded element in this collection.
        Specified by:
        updateEmbeddedElement in interface SCOCollection<java.util.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 java.lang.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​(java.lang.Object element)
        Description copied from class: LinkedHashSet
        Accessor for whether an element is contained in this Set.
        Specified by:
        contains in interface java.util.Collection<E>
        Specified by:
        contains in interface java.util.Set<E>
        Overrides:
        contains in class LinkedHashSet<E>
        Parameters:
        element - The element
        Returns:
        Whether it is contained.

      • containsAll

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

      • equals

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

      • forEach

        public void forEach​(java.util.function.Consumer<? super E> action)
        Specified by:
        forEach in interface java.lang.Iterable<E>
        Overrides:
        forEach in class LinkedHashSet<E>

      • hashCode

        public int hashCode()
        Specified by:
        hashCode in interface java.util.Collection<E>
        Specified by:
        hashCode in interface java.util.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 java.util.Collection<E>
        Specified by:
        isEmpty in interface java.util.Set<E>
        Overrides:
        isEmpty in class LinkedHashSet<E>
        Returns:
        Whether it is empty.

      • iterator

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

      • toArray

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

      • toArray

        public <T> T[] toArray​(T[] a)
        Specified by:
        toArray in interface java.util.Collection<E>
        Specified by:
        toArray in interface java.util.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 java.util.Collection<E>
        Specified by:
        add in interface java.util.Set<E>
        Overrides:
        add in class LinkedHashSet<E>
        Parameters:
        element - The new element
        Returns:
        Whether it was added ok.

      • addAll

        public boolean addAll​(java.util.Collection<? extends E> elements)
        Description copied from class: LinkedHashSet
        Method to add a collection to the LinkedHashSet.
        Specified by:
        addAll in interface java.util.Collection<E>
        Specified by:
        addAll in interface java.util.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 java.util.Collection<E>
        Specified by:
        clear in interface java.util.Set<E>
        Overrides:
        clear in class LinkedHashSet<E>

      • remove

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

      • remove

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

      • writeReplace

        protected java.lang.Object writeReplace()
                                 throws java.io.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:
        java.io.ObjectStreamException - if an error occurs

      • spliterator

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

      • stream

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

      • parallelStream

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