Delegate Factory

using System;
using System.Collections;

namespace Objects
{
	/// <summary>
	/// Summary description for ObjectFactory.
	/// </summary>
	public class ObjectFactory
	{
		#region Static

		/// <summary>
		/// Register handler functions to create new types of objects.
		/// </summary>
		/// <param name="type">The type of the object.</param>
		/// <param name="creator">The handler function.</param>
		/// <returns>true if successful.</returns>
		public static bool RegisterHandler(Int32 type, ObjectCreator creator)
		{
			bool res = false;
			try
			{
				if (m_handlers[type] != null)
					return false;
				// insert the handler to the table according to the type.
				m_handlers[type] = creator;
				res = true;
			}
			catch(Exception ex)
			{
				Console.WriteLine("Can't register handler - "+ex.Message);
			}
			return res;
		}

		/// <summary>
		/// Unregister handler functions according to type.
		/// </summary>
		/// <param name="type">The type of the object.</param>
		/// <returns>true if successful.</returns>
		public static bool UnregisterHandler(Int32 type)
		{
			bool res = true;
			try
			{
				if (m_handlers[type] == null)
					return res;
				// remove the handler to the table according to the type.
				m_handlers[type] = null;
				GC.Collect();
			}
			catch(Exception ex)
			{
				Console.WriteLine("Can't unregister handler - "+ex.Message);
				res = false;
			}
			return res;
		}

		/// <summary>
		/// This is the static method that creates all types of objects.
		/// </summary>
		/// <remarks>Factory method.</remarks>
		/// <param name="type">The key of objects to create.</param>
		/// <param name="list">The parameter list for the object.</param>
		/// <returns>An object.</returns>
		public static AObject CreateObject(Int32 type, params object [] list)
		{
			AObject aobject = null;

			try
			{
				// get the handler that creates the objects
				ObjectCreator creator = (ObjectCreator)m_handlers[type];
				// create the object with the handler.
				if (creator != null)
                    aobject = creator(list);
			}
			catch(Exception ex)
			{
				Console.WriteLine("Can't get object from handler - "+ex.Message);
			}
			return aobject;
		}

		#endregion

		#region Protected

		/// <summary> A table holding the handlers for creating objects. </summary>
		protected static Hashtable m_handlers = new Hashtable();

		#endregion
	}
}