001 package org.apache.turbine.util.template;
002
003
004 /*
005 * Licensed to the Apache Software Foundation (ASF) under one
006 * or more contributor license agreements. See the NOTICE file
007 * distributed with this work for additional information
008 * regarding copyright ownership. The ASF licenses this file
009 * to you under the Apache License, Version 2.0 (the
010 * "License"); you may not use this file except in compliance
011 * with the License. You may obtain a copy of the License at
012 *
013 * http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing,
016 * software distributed under the License is distributed on an
017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
018 * KIND, either express or implied. See the License for the
019 * specific language governing permissions and limitations
020 * under the License.
021 */
022
023
024 import org.apache.commons.logging.Log;
025 import org.apache.commons.logging.LogFactory;
026
027 import org.apache.ecs.ConcreteElement;
028
029 import org.apache.turbine.modules.NavigationLoader;
030
031 import org.apache.turbine.services.template.TurbineTemplate;
032
033 import org.apache.turbine.util.RunData;
034
035 /**
036 * Returns output of a Navigation module. An instance of this is
037 * placed in the WebMacro context by the WebMacroSiteLayout. This
038 * allows template authors to set the navigation template they'd like
039 * to place in their templates. Here's how it's used in a
040 * template:
041 *
042 * <p><code>
043 * $navigation.setTemplate("admin_navigation.wm")
044 * </code>
045 *
046 * @author <a href="mbryson@mont.mindspring.com">Dave Bryson</a>
047 * @version $Id: TemplateNavigation.java 615328 2008-01-25 20:25:05Z tv $
048 */
049 public class TemplateNavigation
050 {
051 /** Logging */
052 private static Log log = LogFactory.getLog(TemplateNavigation.class);
053
054 /* The RunData object. */
055 private RunData data;
056
057 /* The name of the navigation template. */
058 private String template = null;
059
060 /**
061 * Constructor
062 *
063 * @param data A Turbine RunData object.
064 */
065 public TemplateNavigation(RunData data)
066 {
067 this.data = data;
068 }
069
070 /**
071 * Set the template.
072 *
073 * @param template A String with the name of the navigation
074 * template.
075 * @return A TemplateNavigation (self).
076 */
077 public TemplateNavigation setTemplate(String template)
078 {
079 log.debug("setTemplate(" + template + ")");
080 this.template = template;
081 return this;
082 }
083
084 /**
085 * Builds the output of the navigation template.
086 *
087 * @return A String.
088 */
089 public String toString()
090 {
091 String module = null;
092 String returnValue = null;
093
094 try
095 {
096 if (template == null)
097 {
098 returnValue = "Navigation Template is null (Might be unset)";
099 throw new Exception(returnValue);
100 }
101
102 data.getTemplateInfo().setNavigationTemplate(template);
103 module = TurbineTemplate.getNavigationName(template);
104
105 if (module == null)
106 {
107 returnValue = "Template Service returned null for Navigation Template " + template;
108 throw new Exception(returnValue);
109 }
110
111 ConcreteElement results =
112 NavigationLoader.getInstance().eval(data, module);
113 returnValue = results.toString();
114 }
115 catch (Exception e)
116 {
117 if (returnValue == null)
118 {
119 returnValue = "Error processing navigation template: "
120 + template + ", using module: " + module;
121 }
122 log.error(returnValue, e);
123 }
124
125 return returnValue;
126 }
127 }