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}