Name
Hashtable<K,V>
Synopsis
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 ...
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