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.commons.collections4.iterators;
018
019import java.util.Enumeration;
020import java.util.Iterator;
021
022/**
023 * Adapter to make an {@link Iterator Iterator} instance appear to be an
024 * {@link Enumeration Enumeration} instance.
025 *
026 * @since 1.0
027 */
028public class IteratorEnumeration<E> implements Enumeration<E> {
029
030    /** The iterator being decorated. */
031    private Iterator<? extends E> iterator;
032
033    /**
034     * Constructs a new <code>IteratorEnumeration</code> that will not function
035     * until {@link #setIterator(Iterator) setIterator} is invoked.
036     */
037    public IteratorEnumeration() {
038    }
039
040    /**
041     * Constructs a new <code>IteratorEnumeration</code> that will use the given
042     * iterator.
043     *
044     * @param iterator the iterator to use
045     */
046    public IteratorEnumeration(final Iterator<? extends E> iterator) {
047        this.iterator = iterator;
048    }
049
050    // Iterator interface
051    //-------------------------------------------------------------------------
052
053    /**
054     * Returns true if the underlying iterator has more elements.
055     *
056     * @return true if the underlying iterator has more elements
057     */
058    @Override
059    public boolean hasMoreElements() {
060        return iterator.hasNext();
061    }
062
063    /**
064     * Returns the next element from the underlying iterator.
065     *
066     * @return the next element from the underlying iterator.
067     * @throws java.util.NoSuchElementException if the underlying iterator has
068     * no more elements
069     */
070    @Override
071    public E nextElement() {
072        return iterator.next();
073    }
074
075    // Properties
076    //-------------------------------------------------------------------------
077
078    /**
079     * Returns the underlying iterator.
080     *
081     * @return the underlying iterator
082     */
083    public Iterator<? extends E> getIterator() {
084        return iterator;
085    }
086
087    /**
088     * Sets the underlying iterator.
089     *
090     * @param iterator the new underlying iterator
091     */
092    public void setIterator(final Iterator<? extends E> iterator) {
093        this.iterator = iterator;
094    }
095
096}