1 package org.apache.turbine.util.template;
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19 import org.apache.commons.logging.Log;
20 import org.apache.commons.logging.LogFactory;
21
22 import org.apache.ecs.ConcreteElement;
23
24 import org.apache.turbine.modules.NavigationLoader;
25
26 import org.apache.turbine.services.template.TurbineTemplate;
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28 import org.apache.turbine.util.RunData;
29
30 /***
31 * Returns output of a Navigation module. An instance of this is
32 * placed in the WebMacro context by the WebMacroSiteLayout. This
33 * allows template authors to set the navigation template they'd like
34 * to place in their templates. Here's how it's used in a
35 * template:
36 *
37 * <p><code>
38 * $navigation.setTemplate("admin_navigation.wm")
39 * </code>
40 *
41 * @author <a href="mbryson@mont.mindspring.com">Dave Bryson</a>
42 * @version $Id: TemplateNavigation.java 264148 2005-08-29 14:21:04Z henning $
43 */
44 public class TemplateNavigation
45 {
46 /*** Logging */
47 private static Log log = LogFactory.getLog(TemplateNavigation.class);
48
49
50 private RunData data;
51
52
53 private String template = null;
54
55 /***
56 * Constructor
57 *
58 * @param data A Turbine RunData object.
59 */
60 public TemplateNavigation(RunData data)
61 {
62 this.data = data;
63 }
64
65 /***
66 * Set the template.
67 *
68 * @param template A String with the name of the navigation
69 * template.
70 * @return A TemplateNavigation (self).
71 */
72 public TemplateNavigation setTemplate(String template)
73 {
74 log.debug("setTemplate(" + template + ")");
75 this.template = template;
76 return this;
77 }
78
79 /***
80 * Builds the output of the navigation template.
81 *
82 * @return A String.
83 */
84 public String toString()
85 {
86 String module = null;
87 String returnValue = null;
88
89 try
90 {
91 if (template == null)
92 {
93 returnValue = "Navigation Template is null (Might be unset)";
94 throw new Exception(returnValue);
95 }
96
97 data.getTemplateInfo().setNavigationTemplate(template);
98 module = TurbineTemplate.getNavigationName(template);
99
100 if (module == null)
101 {
102 returnValue = "Template Service returned null for Navigation Template " + template;
103 throw new Exception(returnValue);
104 }
105
106 ConcreteElement results =
107 NavigationLoader.getInstance().eval(data, module);
108 returnValue = results.toString();
109 }
110 catch (Exception e)
111 {
112 if (returnValue == null)
113 {
114 returnValue = "Error processing navigation template: "
115 + template + ", using module: " + module;
116 }
117 log.error(returnValue, e);
118 }
119
120 return returnValue;
121 }
122 }