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Java > Open Source Codes > org > apache > turbine > modules > navigations > VelocityNavigation


1 package org.apache.turbine.modules.navigations;
2
3 /*
4  * Copyright 2001-2004 The Apache Software Foundation.
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License")
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18
19 import org.apache.commons.logging.Log;
20 import org.apache.commons.logging.LogFactory;
21
22 import org.apache.ecs.ConcreteElement;
23 import org.apache.ecs.StringElement;
24
25 import org.apache.turbine.TurbineConstants;
26 import org.apache.turbine.services.template.TurbineTemplate;
27 import org.apache.turbine.services.velocity.TurbineVelocity;
28 import org.apache.turbine.util.RunData;
29
30 import org.apache.velocity.context.Context;
31
32 /**
33  * VelocityNavigation. This screen relies on the VelocityPage
34  * being set as the default page. The doBuildTemplate() assumes the
35  * user has put the template filename in the RunData parameter and set
36  * it to the value of the template file to execute. Specialized
37  * Navigations screens should extend this class and overide the
38  * doBuildTemplate( data , context) method.
39  *
40  * @author <a HREF="mailto:mbryson@mont.mindspring.com">Dave Bryson</a>
41  * @author <a HREF="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
42  * @version $Id: VelocityNavigation.java,v 1.5.2.2 2004/05/20 03:03:53 seade Exp $
43  */
44 public class VelocityNavigation
45         extends TemplateNavigation
46 {
47     /** Logging */
48     private static Log log = LogFactory.getLog(VelocityNavigation.class);
49
50     /** The prefix for lookup up navigation pages */
51     private String JavaDoc prefix = TurbineConstants.NAVIGATION_PREFIX + "/";
52
53     /**
54      * Velocity Navigations extending this class should overide this
55      * method to perform any particular business logic and add
56      * information to the context.
57      *
58      * @param data Turbine information.
59      * @param context Context for web pages.
60      * @exception Exception, a generic exception.
61      */
62     protected void doBuildTemplate(RunData data,
63                                    Context context)
64             throws Exception JavaDoc
65     {
66     }
67
68     /**
69      * Needs to be implemented to make TemplateNavigation like us.
70      * The actual method that you should override is the one with the
71      * context in the parameter list.
72      *
73      * @param data Turbine information.
74      * @exception Exception, a generic exception.
75      */
76     protected void doBuildTemplate(RunData data)
77             throws Exception JavaDoc
78     {
79         doBuildTemplate(data, TurbineVelocity.getContext(data));
80     }
81
82     /**
83      * This Builds the Velocity template.
84      *
85      * @param data Turbine information.
86      * @return A ConcreteElement.
87      * @exception Exception, a generic exception.
88      */
89     public ConcreteElement buildTemplate(RunData data)
90             throws Exception JavaDoc
91     {
92         Context context = TurbineVelocity.getContext(data);
93
94         String JavaDoc navigationTemplate = data.getTemplateInfo().getNavigationTemplate();
95         String JavaDoc templateName
96                 = TurbineTemplate.getNavigationTemplateName(navigationTemplate);
97
98         StringElement output = new StringElement();
99         output.setFilterState(false);
100         output.addElement(TurbineVelocity
101                 .handleRequest(context, prefix + templateName));
102         return output;
103     }
104
105 }
106
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