Class Map<K,​V>

  • All Implemented Interfaces:
    Serializable, Cloneable, Map<K,​V>, SCO<Map<K,​V>>, SCOContainer<Map<K,​V>>, SCOMap<Map<K,​V>,​K,​V>, BackedSCO

    public class Map<K,​V>
    extends Map<K,​V>
    implements BackedSCO
    A mutable second-class Map object. Uses a "delegate" as a local store for the Map. Uses a "backing store" (SetStore) to represent the datastore. The "delegate" is updated with the "backing store" information at necessary intervals.

    Modes of Operation

    The user can operate the map 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 map has been loaded from its backing store and does this as necessary. Some methods (size(), containsKey()) just check if everything is loaded and use the delegate if possible, otherwise going direct to the datastore.
    See Also:
    Serialized Form
    • Field Detail

      • allowNulls

        protected transient boolean allowNulls
      • backingStore

        protected transient MapStore<K,​V> backingStore
      • useCache

        protected transient boolean useCache
      • isCacheLoaded

        protected transient boolean isCacheLoaded
    • Constructor Detail

      • Map

        public Map​(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​(Map 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<K>
        Overrides:
        initialise in class Map<K,​V>
        Parameters:
        newValue - New value (to wrap)
        oldValue - Old value (to use in deciding what needs deleting etc)
      • initialise

        public void initialise​(Map m)
        Method to initialise the SCO from an existing value.
        Specified by:
        initialise in interface SCO<K>
        Overrides:
        initialise in class Map<K,​V>
        Parameters:
        m - The object to set from
      • initialise

        public void initialise()
        Method to initialise the SCO for use.
        Specified by:
        initialise in interface SCO<K>
        Overrides:
        initialise in class Map<K,​V>
      • getValue

        public Map getValue()
        Accessor for the unwrapped value that we are wrapping.
        Specified by:
        getValue in interface SCO<K>
        Overrides:
        getValue in class Map<K,​V>
        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<K>
        Overrides:
        load in class Map<K,​V>
      • 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<K>
        Overrides:
        isLoaded in class Map<K,​V>
        Returns:
        Whether it is loaded
      • loadFromStore

        protected void loadFromStore()
        Method to load all elements from the "backing store" where appropriate.
      • updateEmbeddedKey

        public void updateEmbeddedKey​(K key,
                                      int fieldNumber,
                                      Object newValue,
                                      boolean makeDirty)
        Method to update an embedded key in this map.
        Specified by:
        updateEmbeddedKey in interface SCOMap<Map<K,​V>,​K,​V>
        Overrides:
        updateEmbeddedKey in class Map<K,​V>
        Parameters:
        key - The key
        fieldNumber - Number of field in the key
        newValue - New value for this field
        makeDirty - Whether to make the SCO field dirty.
      • updateEmbeddedValue

        public void updateEmbeddedValue​(V value,
                                        int fieldNumber,
                                        Object newValue,
                                        boolean makeDirty)
        Method to update an embedded value in this map.
        Specified by:
        updateEmbeddedValue in interface SCOMap<Map<K,​V>,​K,​V>
        Overrides:
        updateEmbeddedValue in class Map<K,​V>
        Parameters:
        value - The value
        fieldNumber - Number of field in the value
        newValue - 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<K>
        Overrides:
        unsetOwner in class Map<K,​V>
      • 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<K>
        Overrides:
        clone in class Map<K,​V>
        Returns:
        Clone of the object
      • containsKey

        public boolean containsKey​(Object key)
        Utility to check if a key is contained in the Map.
        Specified by:
        containsKey in interface Map<K,​V>
        Overrides:
        containsKey in class Map<K,​V>
        Parameters:
        key - The key to check
        Returns:
        Whether it is contained
      • containsValue

        public boolean containsValue​(Object value)
        Utility to check if a value is contained in the Map.
        Specified by:
        containsValue in interface Map<K,​V>
        Overrides:
        containsValue in class Map<K,​V>
        Parameters:
        value - The value to check
        Returns:
        Whether it is contained
      • entrySet

        public Set entrySet()
        Accessor for the set of entries in the Map.
        Specified by:
        entrySet in interface Map<K,​V>
        Overrides:
        entrySet in class Map<K,​V>
        Returns:
        Set of entries
      • equals

        public boolean equals​(Object o)
        Method to check the equality of this map, and another.
        Specified by:
        equals in interface Map<K,​V>
        Overrides:
        equals in class Map<K,​V>
        Parameters:
        o - The map to compare against.
        Returns:
        Whether they are equal.
      • get

        public V get​(Object key)
        Accessor for the value stored against a key.
        Specified by:
        get in interface Map<K,​V>
        Overrides:
        get in class Map<K,​V>
        Parameters:
        key - The key
        Returns:
        The value.
      • hashCode

        public int hashCode()
        Method to generate a hashcode for this Map.
        Specified by:
        hashCode in interface Map<K,​V>
        Overrides:
        hashCode in class Map<K,​V>
        Returns:
        The hashcode.
      • isEmpty

        public boolean isEmpty()
        Method to return if the Map is empty.
        Specified by:
        isEmpty in interface Map<K,​V>
        Overrides:
        isEmpty in class Map<K,​V>
        Returns:
        Whether it is empty.
      • keySet

        public Set keySet()
        Accessor for the set of keys in the Map.
        Specified by:
        keySet in interface Map<K,​V>
        Overrides:
        keySet in class Map<K,​V>
        Returns:
        Set of keys.
      • size

        public int size()
        Method to return the size of the Map.
        Specified by:
        size in interface Map<K,​V>
        Overrides:
        size in class Map<K,​V>
        Returns:
        The size
      • values

        public Collection values()
        Accessor for the set of values in the Map.
        Specified by:
        values in interface Map<K,​V>
        Overrides:
        values in class Map<K,​V>
        Returns:
        Set of values.
      • toString

        public String toString()
        Method to return a string form of this Map.
        Overrides:
        toString in class AbstractMap<K,​V>
        Returns:
        String form of this Map.
      • clear

        public void clear()
        Method to clear the Map.
        Specified by:
        clear in interface Map<K,​V>
        Overrides:
        clear in class Map<K,​V>
      • put

        public V put​(K key,
                     V value)
        Method to add a value to the Map.
        Specified by:
        put in interface Map<K,​V>
        Overrides:
        put in class Map<K,​V>
        Parameters:
        key - The key for the value.
        value - The value
        Returns:
        The previous value against this key (if any).
      • putAll

        public void putAll​(Map m)
        Method to add a Map of values to this map.
        Specified by:
        putAll in interface Map<K,​V>
        Overrides:
        putAll in class Map<K,​V>
        Parameters:
        m - The Map to add
      • remove

        public V remove​(Object key)
        Method to remove a value from the Map.
        Specified by:
        remove in interface Map<K,​V>
        Overrides:
        remove in class Map<K,​V>
        Parameters:
        key - The key for the value.
        Returns:
        The value removed.
      • 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 Map<K,​V>
        Returns:
        the replaced object
        Throws:
        ObjectStreamException - if an error occurs