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 }