Package com.google.common.collect

Class ForwardingMapEntry<K,​V>

  • All Implemented Interfaces:
    java.util.Map.Entry<K,​V>
    @GwtCompatible
public abstract class ForwardingMapEntry<K,​V>
extends ForwardingObject
implements java.util.Map.Entry<K,​V>
    A map entry which forwards all its method calls to another map entry. Subclasses should override one or more methods to modify the behavior of the backing map entry as desired per the decorator pattern.

    Warning: The methods of ForwardingMapEntry forward indiscriminately to the methods of the delegate. For example, overriding getValue() alone will not change the behavior of equals(java.lang.Object), which can lead to unexpected behavior. In this case, you should override equals as well, either providing your own implementation, or delegating to the provided standardEquals method.

    Each of the standard methods, where appropriate, use Objects.equal(java.lang.Object, java.lang.Object) to test equality for both keys and values. This may not be the desired behavior for map implementations that use non-standard notions of key equality, such as the entry of a SortedMap whose comparator is not consistent with equals.

    The standard methods are not guaranteed to be thread-safe, even when all of the methods that they depend on are thread-safe.

    Since:
    2.0 (imported from Google Collections Library)

    • Constructor Detail

      • ForwardingMapEntry

        protected ForwardingMapEntry()
        Constructor for use by subclasses.

    • Method Detail

      • delegate

        protected abstract java.util.Map.Entry<K,​V> delegate()
        Description copied from class: ForwardingObject
        Returns the backing delegate instance that methods are forwarded to. Abstract subclasses generally override this method with an abstract method that has a more specific return type, such as ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
        Specified by:
        delegate in class ForwardingObject

      • getKey

        public K getKey()
        Specified by:
        getKey in interface java.util.Map.Entry<K,​V>

      • getValue

        public V getValue()
        Specified by:
        getValue in interface java.util.Map.Entry<K,​V>

      • setValue

        public V setValue​(V value)
        Specified by:
        setValue in interface java.util.Map.Entry<K,​V>

      • equals

        public boolean equals​(@Nullable
                      java.lang.Object object)
        Specified by:
        equals in interface java.util.Map.Entry<K,​V>
        Overrides:
        equals in class java.lang.Object

      • hashCode

        public int hashCode()
        Specified by:
        hashCode in interface java.util.Map.Entry<K,​V>
        Overrides:
        hashCode in class java.lang.Object

      • standardEquals

        protected boolean standardEquals​(@Nullable
                                 java.lang.Object object)
        A sensible definition of equals(Object) in terms of getKey() and getValue(). If you override either of these methods, you may wish to override equals(Object) to forward to this implementation.
        Since:
        7.0

      • standardHashCode

        protected int standardHashCode()
        A sensible definition of hashCode() in terms of getKey() and getValue(). If you override either of these methods, you may wish to override hashCode() to forward to this implementation.
        Since:
        7.0