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 * @param <T> The element in the enumeration
035 * 
036 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
037 */
038public class EmptyEnumeration<T> implements NamingEnumeration<T>
039{
040    /**
041     * @see javax.naming.NamingEnumeration#close()
042     */
043    @Override
044    public void close()
045    {
046    }
047
048
049    /**
050     * Always returns false.
051     * 
052     * @see javax.naming.NamingEnumeration#hasMore()
053     */
054    @Override
055    public boolean hasMore() throws NamingException
056    {
057        return false;
058    }
059
060
061    /**
062     * Always throws NoSuchElementException.
063     * 
064     * @see javax.naming.NamingEnumeration#next()
065     */
066    @Override
067    public T next() throws NamingException
068    {
069        throw new NoSuchElementException();
070    }
071
072
073    /**
074     * Always return false.
075     * 
076     * @see java.util.Enumeration#hasMoreElements()
077     */
078    @Override
079    public boolean hasMoreElements()
080    {
081        return false;
082    }
083
084
085    /**
086     * Always throws NoSuchElementException.
087     * 
088     * @see java.util.Enumeration#nextElement()
089     */
090    @Override
091    public T nextElement()
092    {
093        throw new NoSuchElementException();
094    }
095
096}