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.lang.StringUtils;
25 import org.apache.commons.logging.Log;
26 import org.apache.commons.logging.LogFactory;
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 1773378 2016-12-09 13:19:59Z tv $
91 */
92 public class DefaultPage
93 extends Page
94 {
95 /** Logging */
96 protected Log log = LogFactory.getLog(this.getClass());
97
98 /** Injected loader instance */
99 @TurbineLoader( Action.class )
100 protected ActionLoader actionLoader;
101
102 /** Injected loader instance */
103 @TurbineLoader( Screen.class )
104 protected ScreenLoader screenLoader;
105
106 /** Injected loader instance */
107 @TurbineLoader( Layout.class )
108 protected LayoutLoader layoutLoader;
109
110 /**
111 * Builds the Page.
112 *
113 * @param pipelineData Turbine information.
114 * @throws Exception a generic exception.
115 */
116 @Override
117 public void doBuild(PipelineData pipelineData)
118 throws Exception
119 {
120 RunData data = getRunData(pipelineData);
121 // Template pages can use this to set up the context, so it is
122 // available to the Action and Screen. It does nothing here.
123 doBuildBeforeAction(pipelineData);
124
125 // If an action has been defined, execute it here. Actions
126 // can re-define the template definition.
127 if (data.hasAction())
128 {
129 actionLoader.exec(pipelineData, data.getAction());
130 }
131
132 // if a redirect was setup in data, don't do anything else
133 if (StringUtils.isNotEmpty(data.getRedirectURI()))
134 {
135 return;
136 }
137
138 // Template pages can use this to set up default templates and
139 // associated class modules. It does nothing here.
140 doBuildAfterAction(pipelineData);
141
142 String screenName = data.getScreen();
143
144 log.debug("Building " + screenName);
145
146 // Ask the Screen for its Layout and then execute the Layout.
147 // The Screen can override the getLayout() method to re-define
148 // the Layout depending on data passed in via the
149 // data.parameters object.
150 Screen aScreen = screenLoader.getAssembler(screenName);
151 String layout = aScreen.getLayout(pipelineData);
152
153 // If the Layout has been set to be null, attempt to execute
154 // the Screen that has been defined.
155 if (layout != null)
156 {
157 layoutLoader.exec(pipelineData, layout);
158 }
159 else
160 {
161 screenLoader.exec(pipelineData, screenName);
162 }
163
164 // Do any post build actions (overridable by subclasses -
165 // does nothing here).
166 doPostBuild(pipelineData);
167 }
168
169 /**
170 * Can be used by template Pages to stuff the Context into the
171 * PipelineData so that it is available to the Action module and the
172 * Screen module via getContext(). It does nothing here.
173 *
174 * @param pipelineData Turbine information.
175 * @throws Exception a generic exception.
176 */
177 protected void doBuildBeforeAction(PipelineData pipelineData)
178 throws Exception
179 {
180 // do nothing by default
181 }
182
183 /**
184 * Can be overridden by template Pages to set up data needed to
185 * process a template. It does nothing here.
186 *
187 * @param pipelineData Turbine information.
188 * @throws Exception a generic exception.
189 */
190 protected void doBuildAfterAction(PipelineData pipelineData)
191 throws Exception
192 {
193 // do nothing by default
194 }
195
196 /**
197 * Can be overridden to perform actions when the request is
198 * fully processed. It does nothing here.
199 *
200 * @param pipelineData Turbine information.
201 * @throws Exception a generic exception.
202 */
203 protected void doPostBuild(PipelineData pipelineData)
204 throws Exception
205 {
206 // do nothing by default
207 }
208 }