1   /**
2    * Copyright (c) 2000-2007 Liferay, Inc. All rights reserved.
3    *
4    * Permission is hereby granted, free of charge, to any person obtaining a copy
5    * of this software and associated documentation files (the "Software"), to deal
6    * in the Software without restriction, including without limitation the rights
7    * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8    * copies of the Software, and to permit persons to whom the Software is
9    * furnished to do so, subject to the following conditions:
10   *
11   * The above copyright notice and this permission notice shall be included in
12   * all copies or substantial portions of the Software.
13   *
14   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
20   * SOFTWARE.
21   */
22  
23  package com.liferay.portal.struts;
24  
25  import com.liferay.portal.kernel.servlet.HttpHeaders;
26  import com.liferay.portal.kernel.util.ContentTypes;
27  import com.liferay.portal.kernel.util.ParamUtil;
28  import com.liferay.portal.kernel.util.Validator;
29  
30  import java.io.PrintWriter;
31  
32  import javax.servlet.http.HttpServletRequest;
33  import javax.servlet.http.HttpServletResponse;
34  
35  import org.apache.struts.action.Action;
36  import org.apache.struts.action.ActionForm;
37  import org.apache.struts.action.ActionForward;
38  import org.apache.struts.action.ActionMapping;
39  
40  /**
41   * <a href="JSONAction.java.html"><b><i>View Source</i></b></a>
42   *
43   * @author Ming-Gih Lam
44   *
45   */
46  public abstract class JSONAction extends Action {
47  
48      public ActionForward execute(
49              ActionMapping mapping, ActionForm form, HttpServletRequest req,
50              HttpServletResponse res)
51          throws Exception {
52  
53          String callback = ParamUtil.getString(req, "callback");
54          String instance = ParamUtil.getString(req, "inst");
55  
56          String json = null;
57  
58          try {
59              json = getJSON(mapping, form, req, res);
60  
61              if (Validator.isNotNull(callback)) {
62                  json = callback + "(" + json + ");";
63              }
64              else if (Validator.isNotNull(instance)) {
65                  json = "var " + instance + "=" + json + ";";
66              }
67          }
68          catch (Exception e) {
69              res.sendError(
70                  HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e.getMessage());
71  
72              return null;
73          }
74  
75          if (Validator.isNotNull(json)) {
76              res.setContentType(ContentTypes.TEXT_JAVASCRIPT);
77              res.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache");
78  
79              PrintWriter pw = res.getWriter();
80  
81              pw.write(json);
82  
83              pw.close();
84          }
85  
86          return null;
87      }
88  
89      public abstract String getJSON(
90              ActionMapping mapping, ActionForm form, HttpServletRequest req,
91              HttpServletResponse res)
92          throws Exception;
93  
94  }