A GOF Adapter Making Instances of Old Enumeration Interface Behave Like New Iterator Interface

package com.darwinsys;
 
/*
 * Copyright (c) Ian F. Darwin, http://www.darwinsys.com/, 1996-2002.
 * All rights reserved. Software written by Ian F. Darwin and others.
 * $Id: EnumerationIterator.java,v 1.1 2008/08/07 12:42:29 cat Exp $
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 * 
 * Java, the Duke mascot, and all variants of Sun's Java "steaming coffee
 * cup" logo are trademarks of Sun Microsystems. Sun's, and James Gosling's,
 * pioneering role in inventing and promulgating (and standardizing) the Java 
 * language and environment is gratefully acknowledged.
 * 
 * The pioneering role of Dennis Ritchie and Bjarne Stroustrup, of AT&T, for
 * inventing predecessor languages C and C++ is also gratefully acknowledged.
 */
 
import java.util.Enumeration;
import java.util.Iterator;
 
/**
 * A GOF Adapter to make instances of old Enumeration interface behave like new Iterator interface, so we only have to deal with
 * one well-defined implementation of the Iterator pattern.
 */
public class EnumerationIterator implements Iterator {
 
    /** The Enumeration being delegated to */
    private final Enumeration oldEnum;
 
    /**
     * Construct an EnumerationIterator from an old-style Enumeration.
     * 
     * @param old
     *            The Enumeration to be adapted.
     */
    public EnumerationIterator(final Enumeration old) {
	oldEnum = old;
    }
 
    /**
     * Fulfuls the general contract of Iterator.hasNext(), that is, return true as long as there is at least one more item in the
     * Iterator.
     */
    public boolean hasNext() {
	return oldEnum.hasMoreElements();
    }
 
    /**
     * Fulfuls the general contract of Iterator.next(), that is, returns the next element in the Iterator.
     */
    public Object next() {
	return oldEnum.nextElement();
    }
 
    /**
     * Remove is not implemented (optional method).
     * 
     * @throws java.lang.UnsupportedOperationException
     *             in all cases.
     */
    public void remove() {
	throw new UnsupportedOperationException("remove");
    }
}