emptyenumeration.java

来自「精通tomcat书籍原代码,希望大家共同学习」· Java 代码 · 共 42 行

/*
 *  Copyright 1999-2004 The Apache Software Foundation
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

package org.apache.tomcat.util.collections;

import java.util.Enumeration;
import java.util.NoSuchElementException;

public class EmptyEnumeration implements Enumeration {

    static EmptyEnumeration staticInstance=new EmptyEnumeration();

    public EmptyEnumeration() {
    }

    public static Enumeration getEmptyEnumeration() {
	return staticInstance;
    }
    
    public Object nextElement( ) {
	throw new NoSuchElementException( "EmptyEnumeration");
    }

    public boolean hasMoreElements() {
	return false;
    }
    
}