001/*
002 *  Licensed to the Apache Software Foundation (ASF) under one
003 *  or more contributor license agreements.  See the NOTICE file
004 *  distributed with this work for additional information
005 *  regarding copyright ownership.  The ASF licenses this file
006 *  to you under the Apache License, Version 2.0 (the
007 *  "License"); you may not use this file except in compliance
008 *  with the License.  You may obtain a copy of the License at
009 *  
010 *    http://www.apache.org/licenses/LICENSE-2.0
011 *  
012 *  Unless required by applicable law or agreed to in writing,
013 *  software distributed under the License is distributed on an
014 *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 *  KIND, either express or implied.  See the License for the
016 *  specific language governing permissions and limitations
017 *  under the License. 
018 *  
019 */
020package org.apache.directory.api.util;
021
022
023import java.util.NoSuchElementException;
024
025import javax.naming.NamingException;
026import javax.naming.NamingEnumeration;
027
028
029/**
030 * An empty NamingEnumeration without any values: meaning
031 * hasMore/hasMoreElements() always returns false, and next/nextElement() always
032 * throws a NoSuchElementException.
033 * 
034 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
035 */
036public class EmptyEnumeration<T> implements NamingEnumeration<T>
037{
038
039    /**
040     * @see javax.naming.NamingEnumeration#close()
041     */
042    public void close()
043    {
044    }
045
046
047    /**
048     * Always returns false.
049     * 
050     * @see javax.naming.NamingEnumeration#hasMore()
051     */
052    public boolean hasMore() throws NamingException
053    {
054        return false;
055    }
056
057
058    /**
059     * Always throws NoSuchElementException.
060     * 
061     * @see javax.naming.NamingEnumeration#next()
062     */
063    public T next() throws NamingException
064    {
065        throw new NoSuchElementException();
066    }
067
068
069    /**
070     * Always return false.
071     * 
072     * @see java.util.Enumeration#hasMoreElements()
073     */
074    public boolean hasMoreElements()
075    {
076        return false;
077    }
078
079
080    /**
081     * Always throws NoSuchElementException.
082     * 
083     * @see java.util.Enumeration#nextElement()
084     */
085    public T nextElement()
086    {
087        throw new NoSuchElementException();
088    }
089
090}