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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.myfaces.shared.view;
20  
21  import java.io.IOException;
22  import java.io.PrintWriter;
23  
24  import javax.servlet.ServletOutputStream;
25  import javax.servlet.ServletResponse;
26  import javax.servlet.http.HttpServletResponse;
27  import javax.servlet.http.HttpServletResponseWrapper;
28  
29  /**
30   * Implementation of a switching response wrapper to turn 
31   * output on and off according to the JSF spec 2.0.
32   * <p/>
33   * Implemented as HttpServletResponseWrapper,
34   * so that the switching does not interfere with methods that
35   * expect a HttpServletResponse when invoking ExternalContext.getResponse().
36   *
37   * @author Werner Punz (latest modification by $Author: lu4242 $)
38   * @author Jakob Korherr
39   * @version $Revision: 1151677 $ $Date: 2011-07-28 00:03:59 +0000 (Thu, 28 Jul 2011) $
40   */
41  public class HttpServletResponseSwitch extends HttpServletResponseWrapper implements ResponseSwitch
42  {
43      private PrintWriter _switchableWriter;
44      private SwitchableOutputStream _switchableOutputStream;
45      private boolean _enabled = true;
46  
47      public HttpServletResponseSwitch(HttpServletResponse response)
48      {
49          super(response);
50      }
51  
52      /**
53       * Enables or disables the Response's Writer and OutputStream.
54       * @param enabled
55       */
56      public void setEnabled(boolean enabled)
57      {
58          _enabled = enabled;
59      }
60  
61      /**
62       * Are the Response's Writer and OutputStream currently enabled?
63       * @return
64       */
65      public boolean isEnabled()
66      {
67          return _enabled;
68      }
69  
70  
71      @Override
72      public int getBufferSize()
73      {
74          if (isEnabled())
75          {
76              return super.getBufferSize();
77          }
78          return 0;
79      }
80  
81      @Override
82      public boolean isCommitted()
83      {
84          if (isEnabled())
85          {
86              return super.isCommitted();
87          }
88          return false;
89      }
90  
91      @Override
92      public void reset()
93      {
94          if (isEnabled())
95          {
96              super.reset();
97          }
98      }
99  
100     @Override
101     public void resetBuffer()
102     {
103         if (isEnabled())
104         {
105             super.resetBuffer();
106         }
107     }
108     
109     @Override
110     public void flushBuffer() throws IOException
111     {
112         if (isEnabled())
113         {
114             super.flushBuffer();
115         }
116     }
117 
118     @Override
119     public void setResponse(ServletResponse response)
120     {
121         // only change the response if it is not the same object
122         if (response instanceof HttpServletResponse && response != getResponse())
123         {
124             // our OutputStream and our Writer are not valid for the new response
125             _switchableOutputStream = null;
126             _switchableWriter = null;
127             
128             // set the new response
129             super.setResponse(response);
130         }
131     }
132 
133     @Override
134     public ServletOutputStream getOutputStream() throws IOException
135     {
136         if (_switchableOutputStream == null)
137         {
138             _switchableOutputStream = new SwitchableOutputStream(super.getOutputStream(), this);
139         }
140         return _switchableOutputStream;
141     }
142 
143     @Override
144     public PrintWriter getWriter() throws IOException
145     {
146         if (_switchableWriter == null)
147         {
148             _switchableWriter = new PrintWriter(new SwitchableWriter(super.getWriter(), this));
149         }
150         return _switchableWriter;
151     }
152     
153 }