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 * https://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 * @param <T> The element in the enumeration 032 * 033 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a> 034 */ 035public class SingletonEnumeration<T> implements NamingEnumeration<T> 036{ 037 /** The singleton element to return */ 038 private final T element; 039 040 /** Can we return a element */ 041 private boolean hasMore = true; 042 043 044 /** 045 * Creates a NamingEnumeration over a single element. 046 * 047 * @param element The element to store in this enumeration 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 @Override 061 public void close() 062 { 063 hasMore = false; 064 } 065 066 067 /** 068 * @see javax.naming.NamingEnumeration#hasMore() 069 */ 070 @Override 071 public boolean hasMore() 072 { 073 return hasMore; 074 } 075 076 077 /** 078 * @see javax.naming.NamingEnumeration#next() 079 */ 080 @Override 081 public T next() 082 { 083 if ( hasMore ) 084 { 085 hasMore = false; 086 return element; 087 } 088 089 throw new NoSuchElementException(); 090 } 091 092 093 /** 094 * @see java.util.Enumeration#hasMoreElements() 095 */ 096 @Override 097 public boolean hasMoreElements() 098 { 099 return hasMore; 100 } 101 102 103 /** 104 * @see java.util.Enumeration#nextElement() 105 */ 106 @Override 107 public T nextElement() 108 { 109 return next(); 110 } 111}