java.util
Class AbstractSet<E>

java.lang.Object sample code for java.lang.Object definition code for java.lang.Object 
  extended by java.util.AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
      extended by java.util.AbstractSet<E>
All Implemented Interfaces:
Iterable sample code for java.lang.Iterable definition code for java.lang.Iterable <E>, Collection sample code for java.util.Collection definition code for java.util.Collection <E>, Set sample code for java.util.Set definition code for java.util.Set <E>
Direct Known Subclasses:
CopyOnWriteArraySet sample code for java.util.concurrent.CopyOnWriteArraySet definition code for java.util.concurrent.CopyOnWriteArraySet , EnumSet sample code for java.util.EnumSet definition code for java.util.EnumSet , HashSet sample code for java.util.HashSet definition code for java.util.HashSet , TreeSet sample code for java.util.TreeSet definition code for java.util.TreeSet

public abstract class AbstractSet<E>
extends AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
implements Set sample code for java.util.Set definition code for java.util.Set <E>

This class provides a skeletal implementation of the Set interface to minimize the effort required to implement this interface.

The process of implementing a set by extending this class is identical to that of implementing a Collection by extending AbstractCollection, except that all of the methods and constructors in subclasses of this class must obey the additional constraints imposed by the Set interface (for instance, the add method must not permit addition of multiple instances of an object to a set).

Note that this class does not override any of the implementations from the AbstractCollection class. It merely adds implementations for equals and hashCode.

This class is a member of the Java Collections Framework.

Since:
1.2
See Also:
Collection sample code for java.util.Collection definition code for java.util.Collection , AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection , Set sample code for java.util.Set definition code for java.util.Set

Constructor Summary
protected AbstractSet sample code for java.util.AbstractSet.AbstractSet() definition code for java.util.AbstractSet.AbstractSet() ()
          Sole constructor.
 
Method Summary
 boolean equals sample code for java.util.AbstractSet.equals(java.lang.Object) definition code for java.util.AbstractSet.equals(java.lang.Object) (Object sample code for java.lang.Object definition code for java.lang.Object  o)
          Compares the specified object with this set for equality.
 int hashCode sample code for java.util.AbstractSet.hashCode() definition code for java.util.AbstractSet.hashCode() ()
          Returns the hash code value for this set.
 boolean removeAll sample code for java.util.AbstractSet.removeAll(java.util.Collection) definition code for java.util.AbstractSet.removeAll(java.util.Collection) (Collection sample code for java.util.Collection definition code for java.util.Collection <?> c)
          Removes from this set all of its elements that are contained in the specified collection (optional operation).
 
Methods inherited from class java.util.AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection
add sample code for java.util.AbstractCollection.add(E) definition code for java.util.AbstractCollection.add(E) , addAll sample code for java.util.AbstractCollection.addAll(java.util.Collection) definition code for java.util.AbstractCollection.addAll(java.util.Collection) , clear sample code for java.util.AbstractCollection.clear() definition code for java.util.AbstractCollection.clear() , contains sample code for java.util.AbstractCollection.contains(java.lang.Object) definition code for java.util.AbstractCollection.contains(java.lang.Object) , containsAll sample code for java.util.AbstractCollection.containsAll(java.util.Collection) definition code for java.util.AbstractCollection.containsAll(java.util.Collection) , isEmpty sample code for java.util.AbstractCollection.isEmpty() definition code for java.util.AbstractCollection.isEmpty() , iterator sample code for java.util.AbstractCollection.iterator() definition code for java.util.AbstractCollection.iterator() , remove sample code for java.util.AbstractCollection.remove(java.lang.Object) definition code for java.util.AbstractCollection.remove(java.lang.Object) , retainAll sample code for java.util.AbstractCollection.retainAll(java.util.Collection) definition code for java.util.AbstractCollection.retainAll(java.util.Collection) , size sample code for java.util.AbstractCollection.size() definition code for java.util.AbstractCollection.size() , toArray sample code for java.util.AbstractCollection.toArray() definition code for java.util.AbstractCollection.toArray() , toArray sample code for java.util.AbstractCollection.toArray(T[]) definition code for java.util.AbstractCollection.toArray(T[]) , toString sample code for java.util.AbstractCollection.toString() definition code for java.util.AbstractCollection.toString()
 
Methods inherited from class java.lang.Object sample code for java.lang.Object definition code for java.lang.Object
clone sample code for java.lang.Object.clone() definition code for java.lang.Object.clone() , finalize sample code for java.lang.Object.finalize() definition code for java.lang.Object.finalize() , getClass sample code for java.lang.Object.getClass() definition code for java.lang.Object.getClass() , notify sample code for java.lang.Object.notify() definition code for java.lang.Object.notify() , notifyAll sample code for java.lang.Object.notifyAll() definition code for java.lang.Object.notifyAll() , wait sample code for java.lang.Object.wait() definition code for java.lang.Object.wait() , wait sample code for java.lang.Object.wait(long) definition code for java.lang.Object.wait(long) , wait sample code for java.lang.Object.wait(long, int) definition code for java.lang.Object.wait(long, int)
 
Methods inherited from interface java.util.Set sample code for java.util.Set definition code for java.util.Set
add sample code for java.util.Set.add(E) definition code for java.util.Set.add(E) , addAll sample code for java.util.Set.addAll(java.util.Collection) definition code for java.util.Set.addAll(java.util.Collection) , clear sample code for java.util.Set.clear() definition code for java.util.Set.clear() , contains sample code for java.util.Set.contains(java.lang.Object) definition code for java.util.Set.contains(java.lang.Object) , containsAll sample code for java.util.Set.containsAll(java.util.Collection) definition code for java.util.Set.containsAll(java.util.Collection) , isEmpty sample code for java.util.Set.isEmpty() definition code for java.util.Set.isEmpty() , iterator sample code for java.util.Set.iterator() definition code for java.util.Set.iterator() , remove sample code for java.util.Set.remove(java.lang.Object) definition code for java.util.Set.remove(java.lang.Object) , retainAll sample code for java.util.Set.retainAll(java.util.Collection) definition code for java.util.Set.retainAll(java.util.Collection) , size sample code for java.util.Set.size() definition code for java.util.Set.size() , toArray sample code for java.util.Set.toArray() definition code for java.util.Set.toArray() , toArray sample code for java.util.Set.toArray(T[]) definition code for java.util.Set.toArray(T[])
 

Constructor Detail

AbstractSet sample code for java.util.AbstractSet() definition code for java.util.AbstractSet()

protected AbstractSet()
Sole constructor. (For invocation by subclass constructors, typically implicit.)

Method Detail

equals sample code for java.util.AbstractSet.equals(java.lang.Object) definition code for java.util.AbstractSet.equals(java.lang.Object)

public boolean equals(Object sample code for java.lang.Object definition code for java.lang.Object  o)
Compares the specified object with this set for equality. Returns true if the given object is also a set, the two sets have the same size, and every member of the given set is contained in this set. This ensures that the equals method works properly across different implementations of the Set interface.

This implementation first checks if the specified object is this set; if so it returns true. Then, it checks if the specified object is a set whose size is identical to the size of this set; if not, it returns false. If so, it returns containsAll((Collection) o).

Specified by:
equals sample code for java.util.Collection.equals(java.lang.Object) definition code for java.util.Collection.equals(java.lang.Object) in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
equals sample code for java.util.Set.equals(java.lang.Object) definition code for java.util.Set.equals(java.lang.Object) in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
equals sample code for java.lang.Object.equals(java.lang.Object) definition code for java.lang.Object.equals(java.lang.Object) in class Object sample code for java.lang.Object definition code for java.lang.Object
Parameters:
o - Object to be compared for equality with this set.
Returns:
true if the specified object is equal to this set.
See Also:
Object.hashCode() sample code for java.lang.Object.hashCode() definition code for java.lang.Object.hashCode() , Hashtable sample code for java.util.Hashtable definition code for java.util.Hashtable

hashCode sample code for java.util.AbstractSet.hashCode() definition code for java.util.AbstractSet.hashCode()

public int hashCode()
Returns the hash code value for this set. The hash code of a set is defined to be the sum of the hash codes of the elements in the set. This ensures that s1.equals(s2) implies that s1.hashCode()==s2.hashCode() for any two sets s1 and s2, as required by the general contract of Object.hashCode.

This implementation enumerates over the set, calling the hashCode method on each element in the collection, and adding up the results.

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

removeAll sample code for java.util.AbstractSet.removeAll(java.util.Collection<?>) definition code for java.util.AbstractSet.removeAll(java.util.Collection<?>)

public boolean removeAll(Collection sample code for java.util.Collection definition code for java.util.Collection <?> c)
Removes from this set all of its elements that are contained in the specified collection (optional operation).

This implementation determines which is the smaller of this set and the specified collection, by invoking the size method on each. If this set has fewer elements, then the implementation iterates over this set, checking each element returned by the iterator in turn to see if it is contained in the specified collection. If it is so contained, it is removed from this set with the iterator's remove method. If the specified collection has fewer elements, then the implementation iterates over the specified collection, removing from this set each element returned by the iterator, using this set's remove method.

Note that this implementation will throw an UnsupportedOperationException if the iterator returned by the iterator method does not implement the remove method.

Specified by:
removeAll sample code for java.util.Collection.removeAll(java.util.Collection) definition code for java.util.Collection.removeAll(java.util.Collection) in interface Collection sample code for java.util.Collection definition code for java.util.Collection <E>
Specified by:
removeAll sample code for java.util.Set.removeAll(java.util.Collection) definition code for java.util.Set.removeAll(java.util.Collection) in interface Set sample code for java.util.Set definition code for java.util.Set <E>
Overrides:
removeAll sample code for java.util.AbstractCollection.removeAll(java.util.Collection) definition code for java.util.AbstractCollection.removeAll(java.util.Collection) in class AbstractCollection sample code for java.util.AbstractCollection definition code for java.util.AbstractCollection <E>
Parameters:
c - elements to be removed from this set.
Returns:
true if this set changed as a result of the call.
Throws:
UnsupportedOperationException sample code for java.lang.UnsupportedOperationException definition code for java.lang.UnsupportedOperationException - removeAll is not supported by this set.
NullPointerException sample code for java.lang.NullPointerException definition code for java.lang.NullPointerException - if the specified collection is null.
See Also:
AbstractCollection.remove(Object) sample code for java.util.AbstractCollection.remove(java.lang.Object) definition code for java.util.AbstractCollection.remove(java.lang.Object) , AbstractCollection.contains(Object) sample code for java.util.AbstractCollection.contains(java.lang.Object) definition code for java.util.AbstractCollection.contains(java.lang.Object)