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 interface 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 $Id$
34 */
35 @FunctionalInterface
36 public interface Screen extends Assembler
37 {
38 /** Prefix for screen related classes and templates */
39 String PREFIX = "screens";
40
41 /** Property for the size of the screen cache if caching is on */
42 String CACHE_SIZE_KEY = "screen.cache.size";
43
44 /** The default size for the screen cache */
45 int CACHE_SIZE_DEFAULT = 50;
46
47 /** Represents Screen Objects */
48 String NAME = "screen";
49
50 /**
51 * A subclass must implement this method to build itself.
52 * Subclasses override this method to store the screen in RunData
53 * or to write the screen to the output stream referenced in
54 * RunData.
55 * @param pipelineData Turbine information.
56 * @return the content of the screen
57 * @throws Exception a generic exception.
58 */
59 String doBuild(PipelineData pipelineData) throws Exception;
60
61 /**
62 * Subclasses can override this method to add additional
63 * functionality.
64 *
65 * @param pipelineData Turbine information.
66 * @return the content of the screen
67 * @throws Exception a generic exception.
68 */
69 default String build(PipelineData pipelineData)
70 throws Exception
71 {
72 return doBuild(pipelineData);
73 }
74
75 /**
76 * If the Layout has not been defined by the Screen then set the
77 * layout to be "DefaultLayout". The Screen object can also
78 * override this method to provide intelligent determination of
79 * the Layout to execute. You can also define that logic here as
80 * well if you want it to apply on a global scale. For example,
81 * if you wanted to allow someone to define Layout "preferences"
82 * where they could dynamically change the Layout for the entire
83 * site. The information for the request is passed in with the
84 * PipelineData object.
85 *
86 * @param pipelineData Turbine information.
87 * @return A String with the Layout.
88 */
89 default String getLayout(PipelineData pipelineData)
90 {
91 RunData data = pipelineData.getRunData();
92 return data.getLayout();
93 }
94
95 /**
96 * Set the layout for a Screen.
97 *
98 * @param pipelineData Turbine information.
99 * @param layout The layout name.
100 */
101 default void setLayout(PipelineData pipelineData, String layout)
102 {
103 RunData data = pipelineData.getRunData();
104 data.setLayout(layout);
105 }
106 }