1 package org.apache.turbine.modules.pages;
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.commons.lang3.StringUtils;
25 import org.apache.logging.log4j.LogManager;
26 import org.apache.logging.log4j.Logger;
27 import org.apache.turbine.annotation.TurbineLoader;
28 import org.apache.turbine.modules.Action;
29 import org.apache.turbine.modules.ActionLoader;
30 import org.apache.turbine.modules.Layout;
31 import org.apache.turbine.modules.LayoutLoader;
32 import org.apache.turbine.modules.Page;
33 import org.apache.turbine.modules.Screen;
34 import org.apache.turbine.modules.ScreenLoader;
35 import org.apache.turbine.pipeline.PipelineData;
36 import org.apache.turbine.util.RunData;
37
38 /**
39 * When building sites using templates, Screens need only be defined
40 * for templates which require dynamic (database or object) data.
41 *
42 * <p>
43 *
44 * This page can be used on sites where the number of Screens can be
45 * much less than the number of templates. The templates can be
46 * grouped in directories with common layouts. Screen modules are
47 * then expected to be placed in packages corresponding with the
48 * templates' directories and follow a specific naming scheme.
49 *
50 * <p>
51 *
52 * The template parameter is parsed and and a Screen whose package
53 * matches the templates path and shares the same name minus any
54 * extension and beginning with a capital letter is searched for. If
55 * not found, a Screen in a package matching the template's path with
56 * name Default is searched for. If still not found, a Screen with
57 * name Default is looked for in packages corresponding to parent
58 * directories in the template's path until a match is found.
59 *
60 * <p>
61 *
62 * For example if data.getParameters().getString("template") returns
63 * /about_us/directions/driving.wm, the search follows
64 * about_us.directions.Driving, about_us.directions.Default,
65 * about_us.Default, Default, VelocitySiteScreen.
66 *
67 * <p>
68 *
69 * Only one Layout module is used, since it is expected that any
70 * dynamic content will be placed in navigations and screens. The
71 * layout template to be used is found in a similar way to the Screen.
72 * For example the following paths will be searched in the layouts
73 * subdirectory: /about_us/directions/driving.wm,
74 * /about_us/directions/default.wm, /about_us/default.wm, /default.wm.
75 *
76 * <p>
77 *
78 * This approach allows a site with largely static content to be
79 * updated and added to regularly by those with little Java
80 * experience.
81 *
82 * <p>
83 *
84 * The code is an almost a complete clone of the FreeMarkerSitePage
85 * written by John McNally. I've only modified it for Template use.
86 *
87 * @author <a href="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
88 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
89 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
90 * @version $Id: DefaultPage.java 1854797 2019-03-04 20:41:39Z tv $
91 */
92 public class DefaultPage implements Page
93 {
94 /** Logging */
95 protected final Logger log = LogManager.getLogger(this.getClass());
96
97 /** Injected loader instance */
98 @TurbineLoader( Action.class )
99 protected ActionLoader actionLoader;
100
101 /** Injected loader instance */
102 @TurbineLoader( Screen.class )
103 protected ScreenLoader screenLoader;
104
105 /** Injected loader instance */
106 @TurbineLoader( Layout.class )
107 protected LayoutLoader layoutLoader;
108
109 /**
110 * Builds the Page.
111 *
112 * @param pipelineData Turbine information.
113 * @throws Exception a generic exception.
114 */
115 @Override
116 public void doBuild(PipelineData pipelineData)
117 throws Exception
118 {
119 RunData data = pipelineData.getRunData();
120 // Template pages can use this to set up the context, so it is
121 // available to the Action and Screen. It does nothing here.
122 doBuildBeforeAction(pipelineData);
123
124 // If an action has been defined, execute it here. Actions
125 // can re-define the template definition.
126 if (data.hasAction())
127 {
128 actionLoader.exec(pipelineData, data.getAction());
129 }
130
131 // if a redirect was setup in data, don't do anything else
132 if (StringUtils.isNotEmpty(data.getRedirectURI()))
133 {
134 return;
135 }
136
137 // Template pages can use this to set up default templates and
138 // associated class modules. It does nothing here.
139 doBuildAfterAction(pipelineData);
140
141 String screenName = data.getScreen();
142
143 log.debug("Building {}", screenName);
144
145 // Ask the Screen for its Layout and then execute the Layout.
146 // The Screen can override the getLayout() method to re-define
147 // the Layout depending on data passed in via the
148 // data.parameters object.
149 Screen aScreen = screenLoader.getAssembler(screenName);
150 String layout = aScreen.getLayout(pipelineData);
151
152 // If the Layout has been set to be null, attempt to execute
153 // the Screen that has been defined.
154 if (layout != null)
155 {
156 layoutLoader.exec(pipelineData, layout);
157 }
158 else
159 {
160 screenLoader.exec(pipelineData, screenName);
161 }
162
163 // Do any post build actions (overridable by subclasses -
164 // does nothing here).
165 doPostBuild(pipelineData);
166 }
167
168 /**
169 * Can be used by template Pages to stuff the Context into the
170 * PipelineData so that it is available to the Action module and the
171 * Screen module via getContext(). It does nothing here.
172 *
173 * @param pipelineData Turbine information.
174 * @throws Exception a generic exception.
175 */
176 protected void doBuildBeforeAction(PipelineData pipelineData)
177 throws Exception
178 {
179 // do nothing by default
180 }
181
182 /**
183 * Can be overridden by template Pages to set up data needed to
184 * process a template. It does nothing here.
185 *
186 * @param pipelineData Turbine information.
187 * @throws Exception a generic exception.
188 */
189 protected void doBuildAfterAction(PipelineData pipelineData)
190 throws Exception
191 {
192 // do nothing by default
193 }
194
195 /**
196 * Can be overridden to perform actions when the request is
197 * fully processed. It does nothing here.
198 *
199 * @param pipelineData Turbine information.
200 * @throws Exception a generic exception.
201 */
202 protected void doPostBuild(PipelineData pipelineData)
203 throws Exception
204 {
205 // do nothing by default
206 }
207 }