/*
  	 Uiml.Net: a Uiml.Net renderer (http://research.edm.uhasselt.be/kris/research/uiml.net/)
   
	 Copyright (C) 2005  Kris Luyten (kris.luyten@uhasselt.be)
	                     Expertise Centre for Digital Media (http://edm.uhasselt.be)
								Hasselt University

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU Lesser General Public License
	as published by the Free Software Foundation; either version 2.1
	of	the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

namespace Uiml
{

	using System;
	using System.Collections;
	using System.Reflection;

	///<summary>
	/// Serves as a repository of individual registered objects that can be used by the backend and
	/// by the uiml document (behavior, logic, "embedded" scripts
	///</summary>
	public class ExternalObjects : Hashtable 
	{

		private static ExternalObjects m_instance = null;
		private ArrayList m_list;
		private bool m_dirty = true;


		private ExternalObjects() : base()
		{
		}


		public void Add(String key, Object o)
		{
			if(!base.ContainsKey(key))
			{
				base.Add(key,  o);
				m_dirty=true;
			}
		}

		public Object GetObject(String tkey)
		{
			//the Hashtable "Item" property is for languages that do not support operator overloading
			return (Assembly)base[tkey];
		}

		public IEnumerator LoadedObjects
		{
			get {	return base.Values.GetEnumerator(); }
		}

		///<summary>
		///Converts the values in this hashtable into an ArrayList. 
		//To speed things up, the list will be created only the first time,
		//or if m_dirty is set.
		///</summary>
		public ArrayList Objects
		{
			get {
				if((m_list==null)||(m_dirty))
				{
					m_list = new ArrayList();
					IEnumerator v = GetEnumerator();
					while(v.MoveNext())
						m_list.Add(((DictionaryEntry)v.Current).Value);
					m_dirty = false;
				}
				return m_list;
			}
		}
	


		public static ExternalObjects Instance
		{
			get
			{
				if(m_instance == null)
					m_instance = new ExternalObjects();
				return m_instance;
			}

			set { m_instance = value; }
		}
	}
}