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1   package org.apache.turbine.modules.screens;
2   
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  
22  import java.io.BufferedReader;
23  import java.io.CharArrayWriter;
24  import java.io.InputStreamReader;
25  import java.io.OutputStreamWriter;
26  import java.io.PrintWriter;
27  
28  import javax.servlet.http.HttpServletRequest;
29  
30  import org.apache.turbine.pipeline.PipelineData;
31  import org.apache.turbine.services.jsonrpc.TurbineJsonRpc;
32  import org.apache.turbine.util.RunData;
33  
34  import com.metaparadigm.jsonrpc.JSONRPCBridge;
35  
36  /**
37   * A Screen class for dealing with JSON-RPC requests.  Typically you would
38   * extend this class and override the doOutput() method to use TurbineJsonRpc
39   * to register the POJOs that will provide the functions you are making
40   * available via JSON-RPC.  Use JSONSecureScreen if you need the user to be
41   * logged in prior to executing the functions you provide.
42   *
43   * <p>Here is an example from a superclass:
44   * <code>
45   * public void doOutput(RunData data) throws Exception
46   * {
47   *     User user = data.getUser();
48   *
49   *     MyJsonFunctions myFunctions = new MyJsonFunctions(user.getName());
50   *
51   *     // Session specific
52   *     TurbineJsonRpc.registerObject(data.getSession(), "myFunctions", myFunctions);
53   *
54   *     // Global
55   *     //TurbineJsonRpc.registerObjectGlobal("testGlobal", testObject);
56   *
57   *     super.doOutput(data);
58   * }
59   * </code>
60   * 
61   * <p>The class MyFunctions would be something like:
62   * <code>
63   * public class MyJsonFunctions
64   * {
65   *     private String getHello(String clientParameter)
66   *     {
67   *         return "Hello " + clientParameter;
68   *     }
69   * }
70   * </code>
71   *
72   * <p>This code is derived from the com.metaparadigm.jsonrpc.JSONRPCServlet
73   *
74   * @author brad@folkens.com
75   * @author <a href="mailto:seade@backstagetech.com.au">Scott Eade</a>
76   * @version $Id: JSONScreen.java 958672 2010-06-28 18:42:04Z tv $
77   */
78  public class JSONScreen extends RawScreen
79  {
80      protected static final String JSONRPC_CONTENT_TYPE = "text/plain";
81  
82      protected final static int BUFFER_SIZE = 4096;
83  
84      /**
85       * @see org.apache.turbine.modules.screens.RawScreen#getContentType(org.apache.turbine.util.RunData)
86       * @deprecated Use PipelineData version instead.
87       */
88      protected String getContentType(RunData data)
89      {
90          return JSONRPC_CONTENT_TYPE;
91      }
92  
93      /**
94       * @see org.apache.turbine.modules.screens.RawScreen#getContentType(org.apache.turbine.pipeline.PipelineData)
95       */
96      protected String getContentType(PipelineData pipelineData)
97      {
98          return JSONRPC_CONTENT_TYPE;
99      }
100     
101     /**
102      * @see org.apache.turbine.modules.screens.RawScreen#doOutput(org.apache.turbine.util.RunData)
103      */
104     
105     /**
106      * Output the dynamic content.
107      *
108      * @param data The RunData object.
109      * @deprecated Use PipelineData version instead.
110      */
111     protected void doOutput(RunData data) throws Exception
112     {
113         data.declareDirectResponse();
114         HttpServletRequest request = data.getRequest();
115         
116         //String charset = request.getCharacterEncoding();
117         //if(charset == null)
118         //{
119         //    charset = "UTF-8";
120         //}
121         //BufferedReader in = new BufferedReader(new InputStreamReader(request.getInputStream(), charset));
122         BufferedReader in = new BufferedReader(new InputStreamReader(request.getInputStream()));
123 
124         // Read the request
125         CharArrayWriter cdata = new CharArrayWriter();
126         char buf[] = new char[BUFFER_SIZE];
127         int ret;
128         while ((ret = in.read(buf, 0, BUFFER_SIZE)) != -1)
129         {
130             cdata.write(buf, 0, ret);
131         }
132 
133         // Find the JSONRPCBridge for this session or create one
134         // if it doesn't exist
135         JSONRPCBridge json_bridge = TurbineJsonRpc.getBridge(data.getSession());
136 
137         // Process the request
138         Object json_res = TurbineJsonRpc.processCall(cdata, json_bridge, request);
139 
140         PrintWriter out = new PrintWriter(
141                 new OutputStreamWriter(data.getResponse().getOutputStream()));
142         out.print(json_res.toString());
143         out.flush();
144         out.close();
145     }
146 }