/*
 * Copyright 2002-2008 the original author or authors.
 *
 * Licensed under the Apache 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.apache.org/licenses/LICENSE-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.springframework.web.servlet.view.tiles2;

import java.util.Map;

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

import org.apache.tiles.TilesContainer;
import org.apache.tiles.access.TilesAccess;

import org.springframework.web.servlet.support.JstlUtils;
import org.springframework.web.servlet.support.RequestContext;
import org.springframework.web.servlet.view.AbstractUrlBasedView;
import org.springframework.web.util.WebUtils;

/**
 * {@link org.springframework.web.servlet.View} implementation that retrieves a
 * Tiles definition. The "url" property is interpreted as name of a Tiles definition.
 *
 * <p>This class builds on Tiles2, which requires JSP 2.0.
 * JSTL support is integrated out of the box due to JSTL's inclusion in JSP 2.0.
 *
 * <p>Depends on a TilesContainer which must be available in
 * the ServletContext. This container is typically set up via a
 * {@link TilesConfigurer} bean definition in the application context.
 *
 * @author Juergen Hoeller
 * @since 2.5
 * @see #setUrl
 * @see TilesConfigurer
 */
public class TilesView extends AbstractUrlBasedView {

	protected void renderMergedOutputModel(Map model, HttpServletRequest request, HttpServletResponse response)
			throws Exception {

		ServletContext servletContext = getServletContext();
		TilesContainer container = TilesAccess.getContainer(servletContext);
		if (container == null) {
			throw new ServletException("Tiles container is not initialized. " +
					"Have you added a TilesConfigurer to your web application context?");
		}

		exposeModelAsRequestAttributes(model, request);
		JstlUtils.exposeLocalizationContext(new RequestContext(request, servletContext));

		if (!response.isCommitted()) {
			// Tiles is going to use a forward, but some web containers (e.g. OC4J 10.1.3)
			// do not properly expose the Servlet 2.4 forward request attributes... However,
			// must not do this on Servlet 2.5 or above, mainly for GlassFish compatibility.
			ServletContext sc = getServletContext();
			if (sc.getMajorVersion() == 2 && sc.getMinorVersion() < 5) {
				WebUtils.exposeForwardRequestAttributes(request);
			}
		}

		container.render(getUrl(), new Object[] {request, response});
	}

}