enumerator.java

GridSphere 门户 提供一个基于 portlet 的高级开放源代码门户。GridSphere 是在欧盟提供基金的 GridLab 项目下开发的

/*
 * The Apache Software License, Version 1.1
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 * modification, are permitted provided that the following conditions
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 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
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/* 

 */

package org.gridsphere.portlet.impl;

import java.util.*;


/**
 * Uitlity class to wraps an <code>Enumeration</code> around a
 * Collection, i.e. <code>Iterator</code> classes.
 */

public final class Enumerator implements Enumeration {


    // Iterator over which the Enumeration takes place
    private Iterator iterator = null;


    /**
     * Returns an Enumeration over the specified Collection.
     *
     * @param collection Collection with values that should be enumerated
     */
    public Enumerator(Collection collection) {
        this(collection.iterator());
    }


    /**
     * Returns an Enumeration over the values of the
     * specified Iterator.
     *
     * @param iterator Iterator to be wrapped
     */
    public Enumerator(Iterator iterator) {
        super();
        this.iterator = iterator;
    }


    /**
     * Returns an Enumeration over the values of the specified Map.
     *
     * @param map Map with values that should be enumerated
     */
    public Enumerator(Map map) {
        this(map.values().iterator());
    }


    /**
     * Tests if this enumeration contains more elements.
     *
     * @return <code>true</code> if this enumeration contains at
     *         least one more element to provide,
     *         <code>false</code> otherwise.
     */
    public boolean hasMoreElements() {
        return (iterator.hasNext());
    }


    /**
     * Returns the next element of this enumeration.
     *
     * @return the next element of this enumeration
     * @throws NoSuchElementException if no more elements exist
     */
    public Object nextElement() throws NoSuchElementException {
        return (iterator.next());
    }


}