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## com.google.common.collect
Class ForwardingObject

    java.lang.Object
      com.google.common.collect.ForwardingObject

Direct Known Subclasses:
  ForwardingCollection, ForwardingIterator, ForwardingMap, ForwardingMapEntry, ForwardingMultimap

    public abstract class ForwardingObject

extends Object

An abstract base class for implementing the decorator pattern. The `delegate()` method must be overridden to return the instance being decorated. This class does not forward the `hashCode` and `equals` methods through to the backing object, but relies on `Object`'s implementation. This is necessary to preserve the symmetry of `equals`. Custom definitions of equality are usually based on an interface, such as `Set` or `List`, so that the implementation of `equals` can 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 `equals` 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)`. Use an interface-specific subclass of `ForwardingObject`, such as `ForwardingList`, to preserve equality behavior, or override `equals` directly.

The `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.

Author:
  Mike Bostock

Constructor Summary
`protected` | `ForwardingObject()` Sole constructor.

Method Summary
`protected abstract Object` | `delegate()` Returns the backing delegate instance that methods are forwarded to.
`String` | `toString()` Returns the string representation generated by the delegate's `toString` method.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Constructor Detail

### ForwardingObject

    protected ForwardingObject()

  Sole constructor.

Method Detail

### delegate

    protected abstract Object delegate()

  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.

### toString

    public String toString()

  Returns the string representation generated by the delegate's `toString` method.

  Overrides:
    `toString` in class `Object`
  Returns:
    a string representation of the object.

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