/*
 * Copyright (C) 2006-2008 Alfresco Software Limited.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * 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 General Public License for more details.

 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

 * As a special exception to the terms and conditions of version 2.0 of 
 * the GPL, you may redistribute this Program in connection with Free/Libre 
 * and Open Source Software ("FLOSS") applications as described in Alfresco's 
 * FLOSS exception.  You should have recieved a copy of the text describing 
 * the FLOSS exception, and it is also available here: 
 * http://www.alfresco.com/legal/licensing"
 */

package org.alfresco.jlan.server.auth.acl;

import java.util.Hashtable;

import org.springframework.extensions.config.ConfigElement;

/**
 * Access Control Factoy Class
 * 
 * <p>The AccessControlFactory class holds a table of available AccessControlParsers that are used
 * to generate AccessControl instances.
 * 
 * <p>An AccessControlParser has an associated unique type name that is used to call the appropriate parser.
 *
 * @author gkspencer
 */
public class AccessControlFactory {

	//	Access control parsers
	
	private Hashtable<String, AccessControlParser> m_parsers;
	
	/**
	 * Class constructor
	 */
	public AccessControlFactory() {
		m_parsers = new Hashtable<String, AccessControlParser>();
	}

	/**
	 * Create an access control using the specified parameters
	 * 
	 * @param type String
	 * @param params ConfigElement
	 * @return AccessControl
	 * @exception ACLParseException
	 * @exception InvalidACLTypeException
	 */	
	public final AccessControl createAccessControl(String type, ConfigElement params)
		throws ACLParseException, InvalidACLTypeException {
			
		//	Find the access control parser
		
		AccessControlParser parser = m_parsers.get(type);
		if ( parser == null)
			throw new InvalidACLTypeException(type);
			
		//	Parse the parameters and create a new AccessControl instance
		
		return parser.createAccessControl(params); 
	}
	
	/**
	 * Add a parser to the list of available parsers
	 * 
	 * @param parser AccessControlParser
	 */
	public final void addParser(AccessControlParser parser) {
		m_parsers.put(parser.getType(), parser);
	}
	
	/**
	 * Remove a parser from the available parser list
	 * 
	 * @param type String
	 * @return AccessControlParser
	 */
	public final AccessControlParser removeParser(String type) {
		return m_parsers.remove(type);
	}
}