@GwtCompatible public abstract class ForwardingObject extends Object
delegate()method must be overridden to return the instance being decorated.
This class does not forward the
methods through to the backing object, but relies on
implementation. This is necessary to preserve the symmetry of
Custom definitions of equality are usually based on an interface, such as
List, so that the implementation of
cast the object being tested for equality to the custom interface.
ForwardingObject implements no such custom interfaces directly; they
are implemented only in subclasses. Therefore, forwarding
would break symmetry, as the forwarding object might consider itself equal to
the object being tested, but the reverse could not be true. This behavior is
consistent with the JDK's collection wrappers, such as
Collections.unmodifiableCollection(java.util.Collection<? extends T>). Use an
interface-specific subclass of
ForwardingObject, such as
ForwardingList, to preserve equality behavior, or override
toString method is forwarded to the delegate. Although this
class does not implement
Serializable, a serializable subclass may be
created since this class has a parameter-less constructor.
|Modifier||Constructor and Description|
Constructor for use by subclasses.
|Modifier and Type||Method and Description|
Returns the backing delegate instance that methods are forwarded to.
Returns the string representation generated by the delegate's
ForwardingSet.delegate(). Concrete subclasses override this method to supply the instance being decorated.
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