com.google.common.collect
Class ForwardingSet<E>

java.lang.Object
  extended by com.google.common.collect.ForwardingObject
      extended by com.google.common.collect.ForwardingCollection<E>
          extended by com.google.common.collect.ForwardingSet<E>
All Implemented Interfaces:
Iterable<E>, Collection<E>, Set<E>
Direct Known Subclasses:
ForwardingSortedSet

@GwtCompatible
public abstract class ForwardingSet<E>
extends ForwardingCollection<E>
implements Set<E>

A set which forwards all its method calls to another set. Subclasses should override one or more methods to modify the behavior of the backing set as desired per the decorator pattern.

Warning: The methods of ForwardingSet forward indiscriminately to the methods of the delegate. For example, overriding ForwardingCollection.add(E) alone will not change the behavior of ForwardingCollection.addAll(java.util.Collection), which can lead to unexpected behavior. In this case, you should override addAll as well, either providing your own implementation, or delegating to the provided standardAddAll method.

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 (imported from Google Collections Library)
Author:
Kevin Bourrillion, Louis Wasserman

Constructor Summary
protected ForwardingSet()
          Constructor for use by subclasses.
 
Method Summary
protected abstract  Set<E> delegate()
          Returns the backing delegate instance that methods are forwarded to.
 boolean equals(Object object)
          Indicates whether some other object is "equal to" this one.
 int hashCode()
          Returns a hash code value for the object.
protected  boolean standardEquals(Object object)
          A sensible definition of equals(java.lang.Object) in terms of ForwardingCollection.size() and ForwardingCollection.containsAll(java.util.Collection).
protected  int standardHashCode()
          A sensible definition of hashCode() in terms of ForwardingCollection.iterator().
 
Methods inherited from class com.google.common.collect.ForwardingCollection
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, standardAddAll, standardClear, standardContains, standardContainsAll, standardIsEmpty, standardRemove, standardRemoveAll, standardRetainAll, standardToArray, standardToArray, standardToString, toArray, toArray
 
Methods inherited from class com.google.common.collect.ForwardingObject
toString
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface java.util.Set
add, addAll, clear, contains, containsAll, isEmpty, iterator, remove, removeAll, retainAll, size, toArray, toArray
 

Constructor Detail

ForwardingSet

protected ForwardingSet()
Constructor for use by subclasses.

Method Detail

delegate

protected abstract Set<E> 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 delegate(). Concrete subclasses override this method to supply the instance being decorated.

Specified by:
delegate in class ForwardingCollection<E>

equals

public boolean equals(@Nullable
                      Object object)
Description copied from class: java.lang.Object
Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Specified by:
equals in interface Collection<E>
Specified by:
equals in interface Set<E>
Overrides:
equals in class Object
Parameters:
object - the reference object with which to compare.
Returns:
true if this object is the same as the obj argument; false otherwise.
See Also:
Object.hashCode(), Hashtable

hashCode

public int hashCode()
Description copied from class: java.lang.Object
Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.

The general contract of hashCode is:

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)

Specified by:
hashCode in interface Collection<E>
Specified by:
hashCode in interface Set<E>
Overrides:
hashCode in class Object
Returns:
a hash code value for this object.
See Also:
Object.equals(java.lang.Object), Hashtable

standardEquals

@Beta
protected boolean standardEquals(@Nullable
                                      Object object)
A sensible definition of equals(java.lang.Object) in terms of ForwardingCollection.size() and ForwardingCollection.containsAll(java.util.Collection). If you override either of those methods, you may wish to override equals(java.lang.Object) to forward to this implementation.

Since:
7

standardHashCode

@Beta
protected int standardHashCode()
A sensible definition of hashCode() in terms of ForwardingCollection.iterator(). If you override ForwardingCollection.iterator(), you may wish to override equals(java.lang.Object) to forward to this implementation.

Since:
7