1   /**
2    * Copyright (c) 2000-2009 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  import com.liferay.portal.util.PortalUtil;
30  
31  import java.io.PrintWriter;
32  
33  import javax.servlet.http.HttpServletRequest;
34  import javax.servlet.http.HttpServletResponse;
35  
36  import org.apache.struts.action.Action;
37  import org.apache.struts.action.ActionForm;
38  import org.apache.struts.action.ActionForward;
39  import org.apache.struts.action.ActionMapping;
40  
41  /**
42   * <a href="JSONAction.java.html"><b><i>View Source</i></b></a>
43   *
44   * @author Ming-Gih Lam
45   *
46   */
47  public abstract class JSONAction extends Action {
48  
49      public ActionForward execute(
50              ActionMapping mapping, ActionForm form, HttpServletRequest request,
51              HttpServletResponse response)
52          throws Exception {
53  
54          String callback = ParamUtil.getString(request, "callback");
55          String instance = ParamUtil.getString(request, "inst");
56  
57          String json = null;
58  
59          try {
60              json = getJSON(mapping, form, request, response);
61  
62              if (Validator.isNotNull(callback)) {
63                  json = callback + "(" + json + ");";
64              }
65              else if (Validator.isNotNull(instance)) {
66                  json = "var " + instance + "=" + json + ";";
67              }
68          }
69          catch (Exception e) {
70              PortalUtil.sendError(
71                  HttpServletResponse.SC_INTERNAL_SERVER_ERROR, e, request,
72                  response);
73  
74              return null;
75          }
76  
77          if (Validator.isNotNull(json)) {
78              response.setContentType(ContentTypes.TEXT_JAVASCRIPT);
79              response.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache");
80  
81              PrintWriter pw = response.getWriter();
82  
83              pw.write(json);
84  
85              pw.close();
86          }
87  
88          return null;
89      }
90  
91      public abstract String getJSON(
92              ActionMapping mapping, ActionForm form, HttpServletRequest request,
93              HttpServletResponse response)
94          throws Exception;
95  
96  }