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 javax.naming.NamingEnumeration;
024
025import java.util.NoSuchElementException;
026
027
028/**
029 * A NamingEnumeration over a single element.
030 * 
031 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
032 * @param <T> The element in the enumeration
033 */
034public class SingletonEnumeration<T> implements NamingEnumeration<T>
035{
036    /** The singleton element to return */
037    private final T element;
038
039    /** Can we return a element */
040    private boolean hasMore = true;
041
042
043    /**
044     * Creates a NamingEnumeration over a single element.
045     * 
046     * @param element
047     *            TODO
048     */
049    public SingletonEnumeration( final T element )
050    {
051        this.element = element;
052    }
053
054
055    /**
056     * Makes calls to hasMore to false even if we had more.
057     * 
058     * @see javax.naming.NamingEnumeration#close()
059     */
060    public void close()
061    {
062        hasMore = false;
063    }
064
065
066    /**
067     * @see javax.naming.NamingEnumeration#hasMore()
068     */
069    public boolean hasMore()
070    {
071        return hasMore;
072    }
073
074
075    /**
076     * @see javax.naming.NamingEnumeration#next()
077     */
078    public T next()
079    {
080        if ( hasMore )
081        {
082            hasMore = false;
083            return element;
084        }
085
086        throw new NoSuchElementException();
087    }
088
089
090    /**
091     * @see java.util.Enumeration#hasMoreElements()
092     */
093    public boolean hasMoreElements()
094    {
095        return hasMore;
096    }
097
098
099    /**
100     * @see java.util.Enumeration#nextElement()
101     */
102    public T nextElement()
103    {
104        return next();
105    }
106}