@GwtCompatible public abstract class ForwardingMapEntry<K,V> extends ForwardingObject implements 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.equals(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.
| Modifier | Constructor and Description |
|---|---|
protected |
ForwardingMapEntry()
Constructor for use by subclasses.
|
| Modifier and Type | Method and Description |
|---|---|
protected abstract Map.Entry<K,V> |
delegate()
Returns the backing delegate instance that methods are forwarded to.
|
boolean |
equals(Object object) |
K |
getKey() |
V |
getValue() |
int |
hashCode() |
V |
setValue(V value) |
protected boolean |
standardEquals(Object object)
|
protected int |
standardHashCode()
|
protected String |
standardToString()
|
toStringclone, finalize, getClass, notify, notifyAll, wait, wait, waitcomparingByKey, comparingByKey, comparingByValue, comparingByValueprotected ForwardingMapEntry()
Constructor for use by subclasses.
protected abstract Map.Entry<K,V> delegate()
ForwardingObjectReturns 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.
delegate in class ForwardingObjectpublic int hashCode()
protected boolean standardEquals(@Nullable 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.
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.
@Beta protected String standardToString()
A sensible definition of ForwardingObject.toString() in terms of getKey() and getValue(). If you override either of these methods, you may wish to override equals(java.lang.Object) to forward to this implementation.