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1   /*
2    * $Id: VelocityPageFilter.java 475637 2006-11-16 08:32:03Z mrdon $
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *  http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing,
15   * software distributed under the License is distributed on an
16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17   * KIND, either express or implied.  See the License for the
18   * specific language governing permissions and limitations
19   * under the License.
20   */
21  package org.apache.struts2.sitemesh;
22  
23  import java.io.IOException;
24  import java.io.PrintWriter;
25  
26  import javax.servlet.ServletContext;
27  import javax.servlet.ServletException;
28  import javax.servlet.http.HttpServletRequest;
29  import javax.servlet.http.HttpServletResponse;
30  
31  import org.apache.commons.logging.Log;
32  import org.apache.commons.logging.LogFactory;
33  import org.apache.struts2.views.freemarker.FreemarkerManager;
34  import org.apache.struts2.views.velocity.VelocityManager;
35  import org.apache.velocity.Template;
36  import org.apache.velocity.context.Context;
37  
38  import com.opensymphony.module.sitemesh.Decorator;
39  import com.opensymphony.module.sitemesh.HTMLPage;
40  import com.opensymphony.module.sitemesh.Page;
41  import com.opensymphony.xwork2.ActionContext;
42  import com.opensymphony.xwork2.inject.Inject;
43  
44  
45  /***
46   *  Applies Velocity-based decorators
47   *
48   */
49  public class VelocityPageFilter extends TemplatePageFilter {
50      private static final Log LOG = LogFactory.getLog(VelocityPageFilter.class);
51  
52      private static VelocityManager velocityManager;
53      
54      @Inject(required=false)
55      public static void setVelocityManager(VelocityManager mgr) {
56          velocityManager = mgr;
57      }
58          
59      /***
60       *  Applies the decorator, using the relevent contexts
61       *
62       * @param page The page
63       * @param decorator The decorator
64       * @param req The servlet request
65       * @param res The servlet response
66       * @param servletContext The servlet context
67       * @param ctx The action context for this request, populated with the server state
68       */
69      protected void applyDecorator(Page page, Decorator decorator,
70                                    HttpServletRequest req, HttpServletResponse res,
71                                    ServletContext servletContext, ActionContext ctx)
72              throws ServletException, IOException {
73          
74          if (velocityManager == null) {
75              throw new ServletException("Missing freemarker dependency");
76          }
77          
78          try {
79  
80              // init (if needed)
81              velocityManager.init(servletContext);
82  
83              // get encoding
84              String encoding = getEncoding();
85  
86              // get the template and context
87              Template template = velocityManager.getVelocityEngine().getTemplate(decorator.getPage(), encoding);
88              Context context = velocityManager.createContext(ctx.getValueStack(), req, res);
89  
90              // put the page in the context
91              context.put("page", page);
92              if (page instanceof HTMLPage) {
93                  HTMLPage htmlPage = ((HTMLPage) page);
94                  context.put("head", htmlPage.getHead());
95              }
96              context.put("title",page.getTitle());
97              context.put("body",page.getBody());
98  
99              // finally, render it
100             PrintWriter writer = res.getWriter();
101             template.merge(context, writer);
102             writer.flush();
103         } catch (Exception e) {
104             String msg = "Error applying decorator: " + e.getMessage();
105             LOG.error(msg, e);
106             throw new ServletException(msg, e);
107         }
108     }
109 }