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Struts example source code file (VelocityTemplateEngine.java)

This example Struts source code file (VelocityTemplateEngine.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Struts tags/keywords

exception, exception, http, httpservletrequest, httpservletresponse, httpservletresponse, inject, io, ioexception, logger, request, response, servlet, servletcontext, servletcontext, string, string, template, util, velocitytemplateengine

The Struts VelocityTemplateEngine.java source code

/*
 * $Id: VelocityTemplateEngine.java 651946 2008-04-27 13:41:38Z apetrelli $
 *
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.List;
import java.util.Map;

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

import org.apache.struts2.ServletActionContext;
import org.apache.struts2.views.velocity.VelocityManager;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.context.Context;

import com.opensymphony.xwork2.inject.Inject;
import com.opensymphony.xwork2.util.logging.Logger;
import com.opensymphony.xwork2.util.logging.LoggerFactory;

/**
 * Velocity based template engine.
 */
public class VelocityTemplateEngine extends BaseTemplateEngine {
    private static final Logger LOG = LoggerFactory.getLogger(VelocityTemplateEngine.class);
    
    private VelocityManager velocityManager;
    
    @Inject
    public void setVelocityManager(VelocityManager mgr) {
        this.velocityManager = mgr;
    }

    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.init(servletContext);
        VelocityEngine velocityEngine = velocityManager.getVelocityEngine();

        // get the list of templates we can use
        List<Template> templates = templateContext.getTemplate().getPossibleTemplates(this);

        // find the right template
        org.apache.velocity.Template template = null;
        String templateName = null;
        Exception exception = null;
        for (Template t : templates) {
            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";
    }
}

Other Struts examples (source code examples)

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