001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache license, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the license for the specific language governing permissions and
015 * limitations under the license.
016 */
017package org.apache.log4j.helpers;
018
019import java.util.Enumeration;
020import java.util.NoSuchElementException;
021
022/**
023 * An always-empty Enumerator.
024 *
025 * @since version 1.0
026 */
027@SuppressWarnings("rawtypes")
028public final class NullEnumeration implements Enumeration {
029    private static final NullEnumeration INSTANCE = new NullEnumeration();
030
031    private NullEnumeration() {
032    }
033
034    public static NullEnumeration getInstance() {
035        return INSTANCE;
036    }
037
038    @Override
039    public boolean hasMoreElements() {
040        return false;
041    }
042
043    @Override
044    public Object nextElement() {
045        throw new NoSuchElementException();
046    }
047}