/*********************************************************************/
/*                                                                   */
/*                     AgentService Framework                        */
/*                       www.agentservice.it                         */
/*                                                                   */
/* Copyright (C) 2007 l.i.d.o. - DIST, University of Genoa, Italy    */
/* GNU Lesser General Public License                                 */
/*                                                                   */
/* This library 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,             */
/* version 2.1 of the License.                                       */
/*                                                                   */
/* This library 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 library; if not, write to the             */
/* Free Software Foundation, Inc., 59 Temple Place - Suite 330,      */
/* Boston, MA  02111-1307, USA.                                      */
/*                                                                   */
/*********************************************************************/
using AgentService.Ontology;
using AgentService.Ontology.Schema.Abstract;
using System;
using AgentService.Ontology.Validation;

namespace AgentService.Ontology.Schema 
{

	/// <summary>
	/// This class represents the schema of a variable.
	/// </summary>
	public class VariableSchema : TermSchema 
	{
		public static readonly new string base_name = "Variable";
		private static new VariableSchema baseSchema = new VariableSchema();
    
		public static readonly string name = "Name";
		public static readonly string value_type = "Value_type";

		/// <summary>
		/// Constructs a generic schema.
		/// </summary>
		public VariableSchema():base(base_name) 
		{
			try
			{
				Add("Name", BasicOntology.singletonBasicOntology.GetSchema(BasicOntology.BO_string));
				Add("Value_type", BasicOntology.singletonBasicOntology.GetSchema(BasicOntology.BO_string), ObjectSchema.optional);
			}
			catch(Exception ex)
			{
				throw new OntologyException(ex.ToString());
			}
		}

		/// <summary>
		/// Retrieves a generic baseschema for all variables.
		/// </summary>
		/// <returns></returns>
		public static new ObjectSchema GetBaseSchema() 
		{
			return baseSchema;
		}
 
		/// <summary>
		/// A variable can be put whereever a term of whatever type is required.
		/// </summary>
		/// <param name="s"></param>
		/// <returns></returns>
		public new bool IsCompatibleWith(ObjectSchema s) 
		{
			try
			{
				if (s != null) 
				{
					return s.DescendsFrom(TermSchema.GetBaseSchema());
				}
				else 
				{
					return false;
				}
			}
			catch(Exception ex)
			{
				throw new ValidationException(ex.ToString());
			}
		}

		/// <summary>
		/// Returns true if 
		///- s is the base schema for the XXXSchema class and this schema is
		///	 an instance of (e.g. s is ConceptSchema.GetBaseSchema() and this 
		///	 schema is an instance of ConceptSchema)
		///	- s is the base schema for a super-class of the XXXSchema class and
		///	 this schema is an instance of (e.g. s is TermSchema.GetBaseSchema()
		///	 and this schema is an instance of ConceptSchema.
		/// </summary>
		/// <param name="s">Object schema</param>
		/// <returns>Returns true if <code>s</code> is a base schema for this schema.</returns>
		public override bool DescendsFrom(ObjectSchema s) //override?
		{
			try
			{
				if (s != null) 
				{
					if (s.Equals(GetBaseSchema())) 
					{
						return true;
					}
					return base.DescendsFrom(s);
				}
				else 
				{
					return false;
				}
			}
			catch(Exception ex)
			{
				throw new ValidationException(ex.ToString());
			}
		}

		/// <summary>
		/// Returns an abstract object that represents this variable.
		/// </summary>
		/// <returns></returns>
		public override AbsObject NewInstance()  
		{
			return new AbsVariable("Name","Value_type");
										   
		}

	

	}

}