| Java 1.0 | cloneable serializable collection |
This
class implements a hashtable data structure, which maps key objects
to value objects and allows the efficient lookup of the value
associated with a given key. In Java 1.2 and later
Hashtable has been modified to impement the
Map interface. The HashMap
class is typically preferred over this one, although the
synchronized methods of this class are useful in
multi-threaded applications. (But see
java.util.concurrent.ConcurrentHashMap.) In Java
5.0 this class has been made generic along with the
Map interface. The type variable
K represents the type of the hashtable
keys and the type variable V represents
the type of the hashtable values.put( ) associates a value with a key in a
Hashtable. get( ) retrieves a
value for a specified key. remove( ) deletes a
key/value association. keys( ) and
elements( ) return Enumeration
objects that allow you to iterate through the complete set of keys
and values stored in the table. Objects used as keys in a
Hashtable must have valid equals(
) and hashCode( ) methods (the versions
inherited from Object are okay).
null is not legal as a key or value in a
Hashtable.
Figure 16-26. java.util.Hashtable<K,V>
 public class Hashtable<K,V> extends Dictionary<K,V> implements Map<K,V>,
Cloneable, Serializable {
// Public Constructors
public Hashtable ( );
1.2 public Hashtable (Map<? extends K,? extends V> t );
public Hashtable (int initialCapacity );
public Hashtable (int initialCapacity , float loadFactor );
// Public Instance Methods
public void clear ( ); Implements:Map synchronized
public boolean contains (Object value ); synchronized
public boolean containsKey (Object key ); Implements:Map synchronized
public V get (Object key ); Implements:Map synchronized
public boolean isEmpty ( ); Implements:Map synchronized default:true
public V put (K key , V value ); Implements:Map synchronized
public V remove (Object key ); Implements:Map synchronized
public int size ( ); Implements:Map synchronized
// Methods Implementing Map
public void clear ( ); synchronized
public boolean containsKey (Object key ); synchronized
1.2 public boolean containsValue (Object value );
1.2 public Set<Map.Entry<K,V>> entrySet ( );
1.2 public boolean equals (Object o ); synchronized
public V get (Object key ); synchronized
1.2 public int hashCode ( ); synchronized
public boolean isEmpty ( ); synchronized default:true
1.2 public Set<K> keySet ( );
public V put (K key , V value ); synchronized
1.2 public void putAll (Map<? extends K,? extends V> t ); synchronized
public V remove (Object key ); synchronized
public int size ( ); synchronized
1.2 public Collection<V> values ( );
// Public Methods Overriding Dictionary
public Enumeration<V> elements ( ); synchronized
public Enumeration<K> keys ( ); synchronized
// Public Methods Overriding Object
public Object clone ( ); synchronized
public String toString ( ); synchronized
// Protected Instance Methods
protected void rehash ( );
}
Subclasses
Properties |
لطفا منتظر باشید ...
