/*
 * Copyright (c) 2005 Kazuya Ujihara
 * 
 * This software is provided 'as-is', without any express or implied warranty. 
 * In no event will the authors be held liable for any damages arising from the use of this software.
 * 
 * Permission is granted to anyone to use this software for any purpose, 
 * including commercial applications, and to alter it and redistribute it freely, 
 * subject to the following restrictions:
 *   1. The origin of this software must not be misrepresented; 
 *      you must not claim that you wrote the original software. 
 *      If you use this software in a product, an acknowledgment 
 *      in the product documentation would be appreciated but is not required.
 *	 2. Altered source versions must be plainly marked as such, 
 *      and must not be misrepresented as being the original software.
 *	 3. This notice may not be removed or altered from any source distribution.
 */

package jp.ujihara.jsharp.util;

import System.Collections.IEnumerator;
import System.Collections.IEnumerable;
import java.util.Iterator;
import java.util.Enumeration;
import java.util.ConcurrentModificationException;

public class DotNetEnumerator implements IEnumerator
{
	private final static Object NOT_INIT = new Object();
	private Enumeration enumeration;
	private Object current;

	public DotNetEnumerator(Enumeration enumeration)
    {
		if (enumeration == null)
			throw new System.ArgumentNullException();
		this.enumeration = enumeration;
		current = NOT_INIT;
    }

	public DotNetEnumerator(Iterator iterator)
	{
		this(new IteratorEnumeration(iterator));
	}

	public boolean MoveNext() throws System.InvalidOperationException
	{
		try
		{
			boolean r = enumeration.hasMoreElements();
			if (r)
				current = enumeration.nextElement();
			return r;
		}
		catch (ConcurrentModificationException e)
		{
			throw new System.InvalidOperationException(e.getMessage(), e);
		}
	}

	public void Reset() throws System.InvalidOperationException
	{
		throw new System.InvalidOperationException();
	}

	/** @property */
	public Object get_Current() throws System.InvalidOperationException
	{
		if (current == NOT_INIT)
			throw new System.InvalidOperationException();
		return current;
	}
}