001 package org.apache.turbine.modules.screens;
002
003 /*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements. See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership. The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License. You may obtain a copy of the License at
011 *
012 * http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied. See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022
023 // Turbine stuff.
024
025 import org.apache.ecs.ConcreteElement;
026 import org.apache.turbine.modules.Screen;
027 import org.apache.turbine.pipeline.PipelineData;
028 import org.apache.turbine.util.RunData;
029
030 /**
031 * Base class for writing Screens that output binary data. This class
032 * is provided as a helper class for those who want to write Screens
033 * that output raw binary data. For example, it may be extended into
034 * a Screen that outputs a SVG file or a SWF (Flash Player format)
035 * movie. The only thing one has to do is to implement the two
036 * methods <code>getContentType(RunData data)</code> and
037 * <code>doOutput(RunData data)</code> (see below).
038 *
039 * <p> You migth want to take a look at the ImageServer screen class
040 * contained in the TDK.<br>
041 *
042 * @author <a href="mailto:rkoenig@chez.com">Regis Koenig</a>
043 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
044 * @version $Id: RawScreen.java 938645 2010-04-27 20:57:51Z tv $
045 */
046 public abstract class RawScreen extends Screen
047 {
048 /**
049 * Build the Screen. This method actually makes a call to the
050 * doOutput() method in order to generate the Screen content.
051 *
052 * @deprecated Use PipelineData version instead.
053 * @param data Turbine information.
054 * @return A ConcreteElement.
055 * @exception Exception, a generic exception.
056 */
057 protected final ConcreteElement doBuild(RunData data)
058 throws Exception
059 {
060 data.getResponse().setContentType(getContentType(data));
061 data.declareDirectResponse();
062 doOutput(data);
063 return null;
064 }
065
066 /**
067 * Build the Screen. This method actually makes a call to the
068 * doOutput() method in order to generate the Screen content.
069 *
070 * @param data Turbine information.
071 * @return A ConcreteElement.
072 * @exception Exception, a generic exception.
073 */
074 protected final ConcreteElement doBuild(PipelineData pipelineData)
075 throws Exception
076 {
077 RunData data = getRunData(pipelineData);
078 return doBuild(data);
079 }
080
081
082 /**
083 * Set the content type. This method should be overidden to
084 * actually set the real content-type header of the output.
085 *
086 * @deprecated Use PipelineData version instead.
087 * @param data Turbine information.
088 * @return A String with the content type.
089 */
090 protected abstract String getContentType(RunData data);
091
092 /**
093 * Set the content type. This method should be overidden to
094 * actually set the real content-type header of the output.
095 *
096 * @param data Turbine information.
097 * @return A String with the content type.
098 */
099 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 }