1   // ========================================================================
2   // Copyright 2007 Mort Bay Consulting Pty. Ltd.
3   // ------------------------------------------------------------------------
4   // Licensed under the Apache License, Version 2.0 (the "License");
5   // you may not use this file except in compliance with the License.
6   // You may obtain a copy of the License at 
7   // http://www.apache.org/licenses/LICENSE-2.0
8   // Unless required by applicable law or agreed to in writing, software
9   // distributed under the License is distributed on an "AS IS" BASIS,
10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
11  // See the License for the specific language governing permissions and
12  // limitations under the License.
13  //========================================================================
14  
15  package org.mortbay.cometd;
16  
17  import java.io.IOException;
18  import java.io.PrintWriter;
19  
20  import javax.servlet.http.HttpServletResponse;
21  
22  import org.mortbay.util.ajax.JSON;
23  
24  import dojox.cometd.Message;
25  
26  /* ------------------------------------------------------------ */
27  /**
28   * @author aabeling
29   * @author gregw
30   * 
31   */
32  public class JSONPTransport extends AbstractTransport
33  {
34      public final static String __DEFAULT_CALLBACK="jsonpcallback";
35      int _responses=0;
36      PrintWriter _out;
37      String _jsonp= null;
38      boolean _commented;
39      String _mimeType;
40      
41      public JSONPTransport(boolean commented,String jsonp)
42      {
43          setJSONCommented(commented);
44          _commented=commented;
45          _jsonp=jsonp;
46      }
47      
48      public void send(Message message) throws IOException
49      {
50          if (message!=null)
51          {
52              if (_responses==0)
53              {
54                  HttpServletResponse response=getResponse();
55                  response.setContentType(_mimeType);
56                  _out=response.getWriter();
57                  if (_commented)
58                      _out.write("/*");
59                  _out.write(this._jsonp==null?__DEFAULT_CALLBACK:_jsonp);
60                  _out.write("([");
61              }
62              else
63              {
64                  _out.write(",\r\n");
65              }
66  
67              String r=(message instanceof MessageImpl)
68                  ?((MessageImpl)message).getJSON()
69                  :JSON.toString(message);
70              ((MessageImpl)message).decRef();
71              _responses++;
72              _out.write(r);
73          }
74      }
75  
76      public void complete() throws IOException
77      {
78          HttpServletResponse response=getResponse();
79          response.setStatus(200);
80  
81          if (_responses==0)
82          {
83              response.setContentType(_mimeType);
84              _out=response.getWriter();
85              if (_commented)
86                  _out.write("/*");
87              _out.write(this._jsonp==null?__DEFAULT_CALLBACK:_jsonp);
88              _out.write("([");
89          }
90          if (_commented)
91              _out.write("])*/\r\n");
92          else
93              _out.write("])\r\n");
94          _out.flush();
95      }
96  
97      /* ------------------------------------------------------------ */
98      public boolean resumePoll()
99      {
100         return true;
101     }
102 
103     /* ------------------------------------------------------------ */
104     public String getJsonp()
105     {
106         return _jsonp;
107     }
108 
109     /* ------------------------------------------------------------ */
110     public String toString()
111     {
112         return "JSONPTransport[jsonp="+this._jsonp+"]";
113     }
114 
115     /* ------------------------------------------------------------ */
116     /**
117      * @return the commented
118      */
119     public boolean isJSONCommented()
120     {
121         return _commented;
122     }
123 
124     /* ------------------------------------------------------------ */
125     /**
126      * @param commented the commented to set
127      */
128     public void setJSONCommented(boolean commented)
129     {
130         _commented=commented;
131         _mimeType=commented?"text/javascript-comment-filtered; charset=utf-8":"text/javascript; charset=utf-8";
132     }
133 }