/*
* $Id: VelocityTemplateEngine.java 439747 2006-09-03 09:22:46Z mrdon $
*
* Copyright 2006 The Apache Software Foundation.
*
* 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.apache.struts2.components.template;
import java.io.IOException;
import java.io.Writer;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts2.ServletActionContext;
import org.apache.struts2.views.velocity.VelocityManager;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.context.Context;
/**
* Velocity based template engine.
*/
public class VelocityTemplateEngine extends BaseTemplateEngine {
private static final Log LOG = LogFactory.getLog(VelocityTemplateEngine.class);
public void renderTemplate(TemplateRenderingContext templateContext) throws Exception {
// get the various items required from the stack
Map actionContext = templateContext.getStack().getContext();
ServletContext servletContext = (ServletContext) actionContext.get(ServletActionContext.SERVLET_CONTEXT);
HttpServletRequest req = (HttpServletRequest) actionContext.get(ServletActionContext.HTTP_REQUEST);
HttpServletResponse res = (HttpServletResponse) actionContext.get(ServletActionContext.HTTP_RESPONSE);
// prepare velocity
VelocityManager velocityManager = VelocityManager.getInstance();
velocityManager.init(servletContext);
VelocityEngine velocityEngine = velocityManager.getVelocityEngine();
// get the list of templates we can use
List templates = templateContext.getTemplate().getPossibleTemplates(this);
// find the right template
org.apache.velocity.Template template = null;
String templateName = null;
Exception exception = null;
for (Iterator iterator = templates.iterator(); iterator.hasNext();) {
Template t = (Template) iterator.next();
templateName = getFinalTemplateName(t);
try {
// try to load, and if it works, stop at the first one
template = velocityEngine.getTemplate(templateName);
break;
} catch (IOException e) {
if (exception == null) {
exception = e;
}
}
}
if (template == null) {
LOG.error("Could not load template " + templateContext.getTemplate());
if (exception != null) {
throw exception;
} else {
return;
}
}
if (LOG.isDebugEnabled()) {
LOG.debug("Rendering template " + templateName);
}
Context context = velocityManager.createContext(templateContext.getStack(), req, res);
Writer outputWriter = templateContext.getWriter();
context.put("tag", templateContext.getTag());
context.put("parameters", templateContext.getParameters());
template.merge(context, outputWriter);
}
protected String getSuffix() {
return "vm";
}
}