This
abstract class is a partial implementation of
Collection that makes it easy to define custom
Collection implementations. To create an
unmodifiable collection, simply override size(
) and iterator( ). The
Iterator object returned by iterator(
) has to support only the hasNext( ) and
next( ) methods. To define a modifiable
collection, you must additionally override the add(
) method of
AbstractCollection and make sure the
Iterator returned by iterator(
) supports the remove(
) method. Some subclasses may choose
to override other methods to tune performance. In addition, it is
conventional that all subclasses provide two constructors: one that
takes no arguments and one that accepts a
Collection argument that specifies the initial
contents of the collection.
Note that if you subclass AbstractCollection
directly, you are implementing a
bagan
unordered collection that allows duplicate
elements. If your add( ) method rejects duplicate
elements, you should subclass AbstractSet instead.
See also AbstractList.
public abstract class AbstractCollection<E> implements Collection<E> {
// Protected Constructors
protected AbstractCollection( );
// Methods Implementing Collection
public boolean add(E o);
public boolean addAll(Collection<? extends E> c);
public void clear( );
public boolean contains(Object o);
public boolean containsAll(Collection<?> c);
public boolean isEmpty( );
public abstract Iterator<E> iterator( );
public boolean remove(Object o);
public boolean removeAll(Collection<?> c);
public boolean retainAll(Collection<?> c);
public abstract int size( );
public Object[ ] toArray( );
public <T> T[ ] toArray(T[ ] a);
// Public Methods Overriding Object
public String toString( );
}
