1 package org.apache.turbine.modules;
2
3
4 /*
5 * Licensed to the Apache Software Foundation (ASF) under one
6 * or more contributor license agreements. See the NOTICE file
7 * distributed with this work for additional information
8 * regarding copyright ownership. The ASF licenses this file
9 * to you under the Apache License, Version 2.0 (the
10 * "License"); you may not use this file except in compliance
11 * with the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing,
16 * software distributed under the License is distributed on an
17 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
18 * KIND, either express or implied. See the License for the
19 * specific language governing permissions and limitations
20 * under the License.
21 */
22
23
24 import org.apache.turbine.pipeline.PipelineData;
25 import org.apache.turbine.util.RunData;
26
27 /**
28 * This is the base class which defines the Screen modules.
29 *
30 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
31 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
32 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
33 * @version $Id: Screen.java 1709648 2015-10-20 17:08:10Z tv $
34 */
35 public abstract class Screen
36 extends Assembler
37 {
38 /** Prefix for screen related classes and templates */
39 public static final String PREFIX = "screens";
40
41 /** Property for the size of the screen cache if caching is on */
42 public static final String CACHE_SIZE_KEY = "screen.cache.size";
43
44 /** The default size for the screen cache */
45 public static final int CACHE_SIZE_DEFAULT = 50;
46
47 /** Represents Screen Objects */
48 public static final String NAME = "screen";
49
50 /**
51 * @see org.apache.turbine.modules.Assembler#getPrefix()
52 */
53 @Override
54 public String getPrefix()
55 {
56 return PREFIX;
57 }
58
59 /**
60 * A subclass must override this method to build itself.
61 * Subclasses override this method to store the screen in RunData
62 * or to write the screen to the output stream referenced in
63 * RunData.
64 * @param pipelineData Turbine information.
65 * @return the content of the screen
66 * @exception Exception a generic exception.
67 */
68 protected abstract String doBuild(PipelineData pipelineData) throws Exception;
69
70 /**
71 * Subclasses can override this method to add additional
72 * functionality. This method is protected to force clients to
73 * use ScreenLoader to build a Screen.
74 *
75 * @param pipelineData Turbine information.
76 * @return the content of the screen
77 * @exception Exception a generic exception.
78 */
79 protected String build(PipelineData pipelineData)
80 throws Exception
81 {
82 return doBuild(pipelineData);
83 }
84
85 /**
86 * If the Layout has not been defined by the Screen then set the
87 * layout to be "DefaultLayout". The Screen object can also
88 * override this method to provide intelligent determination of
89 * the Layout to execute. You can also define that logic here as
90 * well if you want it to apply on a global scale. For example,
91 * if you wanted to allow someone to define Layout "preferences"
92 * where they could dynamically change the Layout for the entire
93 * site. The information for the request is passed in with the
94 * PipelineData object.
95 *
96 * @param pipelineData Turbine information.
97 * @return A String with the Layout.
98 */
99 public String getLayout(PipelineData pipelineData)
100 {
101 RunData data = getRunData(pipelineData);
102 return data.getLayout();
103 }
104
105 /**
106 * Set the layout for a Screen.
107 *
108 * @param pipelineData Turbine information.
109 * @param layout The layout name.
110 */
111 public void setLayout(PipelineData pipelineData, String layout)
112 {
113 RunData data = getRunData(pipelineData);
114 data.setLayout(layout);
115 }
116 }