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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  
23  // Turbine stuff.
24  
25  import org.apache.ecs.ConcreteElement;
26  import org.apache.turbine.modules.Screen;
27  import org.apache.turbine.pipeline.PipelineData;
28  import org.apache.turbine.util.RunData;
29  
30  /**
31   * Base class for writing Screens that output binary data.  This class
32   * is provided as a helper class for those who want to write Screens
33   * that output raw binary data.  For example, it may be extended into
34   * a Screen that outputs a SVG file or a SWF (Flash Player format)
35   * movie.  The only thing one has to do is to implement the two
36   * methods <code>getContentType(RunData data)</code> and
37   * <code>doOutput(RunData data)</code> (see below).
38   *
39   * <p> You migth want to take a look at the ImageServer screen class
40   * contained in the TDK.<br>
41   *
42   * @author <a href="mailto:rkoenig@chez.com">Regis Koenig</a>
43   * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
44   * @version $Id: RawScreen.java 938645 2010-04-27 20:57:51Z tv $
45   */
46  public abstract class RawScreen extends Screen
47  {
48      /**
49       * Build the Screen.  This method actually makes a call to the
50       * doOutput() method in order to generate the Screen content.
51       *
52       * @deprecated Use PipelineData version instead.
53       * @param data Turbine information.
54       * @return A ConcreteElement.
55       * @exception Exception, a generic exception.
56       */
57      protected final ConcreteElement doBuild(RunData data)
58              throws Exception
59      {
60          data.getResponse().setContentType(getContentType(data));
61          data.declareDirectResponse();
62          doOutput(data);
63          return null;
64      }
65  
66      /**
67       * Build the Screen.  This method actually makes a call to the
68       * doOutput() method in order to generate the Screen content.
69       *
70       * @param data Turbine information.
71       * @return A ConcreteElement.
72       * @exception Exception, a generic exception.
73       */
74      protected final ConcreteElement doBuild(PipelineData pipelineData)
75              throws Exception
76      {
77          RunData data = getRunData(pipelineData);
78          return doBuild(data);
79      }
80  
81  
82      /**
83       * Set the content type.  This method should be overidden to
84       * actually set the real content-type header of the output.
85       *
86       * @deprecated Use PipelineData version instead.
87       * @param data Turbine information.
88       * @return A String with the content type.
89       */
90      protected abstract String getContentType(RunData data);
91  
92      /**
93       * Set the content type.  This method should be overidden to
94       * actually set the real content-type header of the output.
95       *
96       * @param data Turbine information.
97       * @return A String with the content type.
98       */
99      protected String getContentType(PipelineData pipelineData)
100     {
101         RunData data = getRunData(pipelineData);
102         return getContentType(data);
103     }
104 
105 
106     /**
107      * Actually output the dynamic content.  The OutputStream can be
108      * accessed like this: <pre>OutputStream out =
109      * data.getResponse().getOutputStream();</pre>.
110      *
111      * @deprecated Use PipelineData version instead.
112      * @param data Turbine information.
113      * @exception Exception, a generic exception.
114      */
115     protected abstract void doOutput(RunData data)
116             throws Exception;
117 
118     /**
119      * Actually output the dynamic content.  The OutputStream can be
120      * accessed like this: <pre>OutputStream out =
121      * data.getResponse().getOutputStream();</pre>.
122      *
123      * @param data Turbine information.
124      * @exception Exception, a generic exception.
125      */
126     protected void doOutput(PipelineData pipelineData)
127             throws Exception
128     {
129         RunData data = getRunData(pipelineData);
130         doOutput(data);
131     }
132 
133 
134     /**
135      * The layout must be set to null.
136      *
137      * @deprecated Use PipelineData version instead.
138      * @param data Turbine information.
139      * @return A null String.
140      */
141     public final String getLayout(RunData data)
142     {
143         return null;
144     }
145 
146     /**
147      * The layout must be set to null.
148      *
149      * @param data Turbine information.
150      * @return A null String.
151      */
152     public final String getLayout(PipelineData pipelineData)
153     {
154         return null;
155     }
156 
157 
158 
159 }