/**********************************************************************************
 * $URL: https://source.sakaiproject.org/svn/portal/trunk/portal-api/api/src/java/org/sakaiproject/portal/api/PortalRenderEngine.java $
 * $Id: PortalRenderEngine.java 105079 2012-02-24 23:08:11Z ottenhoff@longsight.com $
 ***********************************************************************************
 *
 * Copyright (c) 2005, 2006, 2007, 2008 The Sakai Foundation
 *
 * Licensed under the Educational Community License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.opensource.org/licenses/ECL-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 **********************************************************************************/

package org.sakaiproject.portal.api;

import java.io.Writer;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.sakaiproject.tool.api.Placement;

/**
 * Repesents the API used by the protal to comunicate with the RenderEngine
 * implimentation.
 * 
 * @author ieb
 * @since Sakai 2.4
 * @version $Rev: 105079 $
 * 
 */
public interface PortalRenderEngine
{

	/**
	 * Initialise the render engine
	 * 
	 * @throws Exception
	 */
	void init() throws Exception;

	/**
	 * generate a non thread safe render context for the current
	 * request/thread/operation
	 * 
	 * @param request
	 * @return
	 */
	PortalRenderContext newRenderContext(HttpServletRequest request);

	/**
	 * Render a PortalRenderContext against a template. The real template may be
	 * based on a skining name, out output will be send to the Writer
	 * 
	 * @param template
	 * @param rcontext
	 * @param out
	 * @throws Exception
	 */
	void render(String template, PortalRenderContext rcontext, Writer out)
			throws Exception;

	/**
	 * prepare for a forward operation in the render engine, this might include
	 * modifying the request attributes.
	 * 
	 * @param req
	 * @param res
	 * @param p
	 * @param skin
	 */
	void setupForward(HttpServletRequest req, HttpServletResponse res, Placement p,
			String skin);

}