/*

 * Copyright 1994-2005 Sun Microsystems, Inc.  All Rights Reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Sun designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Sun in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 */

package java.util;

/**

 * 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<E> 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.

     *

     * @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.

     *

     * @return     the next element of this enumeration.

     * @exception  NoSuchElementException  if no more elements exist.

     */

    E nextElement();

}