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package java.util;


An object that implements the Enumeration interface generates a
series of elements, one at a time. Successive calls to the
nextElement method return successive elements of the
series.


For example, to print all elements of a Vector<E> v:

  for (Enumeration<E> e = v.elements(); e.hasMoreElements();)
      System.out.println(e.nextElement());



Methods are provided to enumerate through the elements of a
vector, the keys of a hashtable, and the values in a hashtable.
Enumerations are also used to specify the input streams to a
SequenceInputStream.


NOTE: The functionality of this interface is duplicated by the Iterator
interface.  In addition, Iterator adds an optional remove operation, and
has shorter method names.  New implementations should consider using
Iterator in preference to Enumeration.

Author: Lee Boynton
See Also:
Since:  JDK1.0
/**
 * An object that implements the Enumeration interface generates a
 * series of elements, one at a time. Successive calls to the
 * <code>nextElement</code> method return successive elements of the
 * series.
 * <p>
 * For example, to print all elements of a <tt>Vector&lt;E&gt;</tt> <i>v</i>:
 * <pre>
 *   for (Enumeration&lt;E&gt; e = v.elements(); e.hasMoreElements();)
 *       System.out.println(e.nextElement());</pre>
 * <p>
 * Methods are provided to enumerate through the elements of a
 * vector, the keys of a hashtable, and the values in a hashtable.
 * Enumerations are also used to specify the input streams to a
 * <code>SequenceInputStream</code>.
 * <p>
 * NOTE: The functionality of this interface is duplicated by the Iterator
 * interface.  In addition, Iterator adds an optional remove operation, and
 * has shorter method names.  New implementations should consider using
 * Iterator in preference to Enumeration.
 *
 * @see     java.util.Iterator
 * @see     java.io.SequenceInputStream
 * @see     java.util.Enumeration#nextElement()
 * @see     java.util.Hashtable
 * @see     java.util.Hashtable#elements()
 * @see     java.util.Hashtable#keys()
 * @see     java.util.Vector
 * @see     java.util.Vector#elements()
 *
 * @author  Lee Boynton
 * @since   JDK1.0
 */
public interface Enumeration<E> {
    
Tests if this enumeration contains more elements.

Returns: true if and only if this enumeration object
          contains at least one more element to provide;
         false otherwise.
/**
     * Tests if this enumeration contains more elements.
     *
     * @return  <code>true</code> if and only if this enumeration object
     *           contains at least one more element to provide;
     *          <code>false</code> otherwise.
     */
    boolean hasMoreElements();

    
Returns the next element of this enumeration if this enumeration
object has at least one more element to provide.

Throws:
Returns:    the next element of this enumeration.
/**
     * Returns the next element of this enumeration if this enumeration
     * object has at least one more element to provide.
     *
     * @return     the next element of this enumeration.
     * @exception  NoSuchElementException  if no more elements exist.
     */
    E nextElement();
}