001    package org.apache.turbine.services.template.mapper;
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 java.util.ArrayList;
025    import java.util.Arrays;
026    import java.util.List;
027    
028    import org.apache.commons.lang.StringUtils;
029    import org.apache.commons.logging.Log;
030    import org.apache.commons.logging.LogFactory;
031    import org.apache.turbine.services.template.TemplateEngineService;
032    import org.apache.turbine.services.template.TemplateService;
033    import org.apache.turbine.services.template.TurbineTemplate;
034    
035    /**
036     * This mapper is responsible for the lookup of templates for the Layout
037     * It tries to look in various packages for a match:
038     *
039     * 1. about,directions,Driving.vm      <- exact match
040     * 2. about,directions,Default.vm      <- package match, Default name
041     * 3. about,Default.vm                 <- stepping up in the hierarchy
042     * 4. Default.vm                       <- The name configured as default.layout.template
043     *                                        in the corresponding Templating Engine
044    
045     *
046     * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
047     * @version $Id: LayoutTemplateMapper.java 1071091 2011-02-15 22:06:55Z tv $
048     */
049    
050    public class LayoutTemplateMapper
051        extends BaseTemplateMapper
052        implements Mapper
053    {
054        /** Logging */
055        private static Log log = LogFactory.getLog(LayoutTemplateMapper.class);
056    
057        /**
058         * Default C'tor. If you use this C'tor, you must use
059         * the bean setter to set the various properties needed for
060         * this mapper before first usage.
061         */
062        public LayoutTemplateMapper()
063        {
064            // empty
065        }
066    
067        /**
068         * Look for a given Template, then try the
069         * defaults until we hit the root.
070         *
071         * @param template The template name.
072         * @return The parsed module name.
073         */
074        public String doMapping(String template)
075        {
076            log.debug("doMapping(" + template + ")");
077            // Copy our elements into an array
078            List<String> components
079                = new ArrayList<String>(Arrays.asList(StringUtils.split(
080                                                  template,
081                                                  String.valueOf(TemplateService.TEMPLATE_PARTS_SEPARATOR))));
082            int componentSize = components.size() - 1 ;
083    
084            // This method never gets an empty string passed.
085            // So this is never < 0
086            String templateName = components.get(componentSize);
087            components.remove(componentSize--);
088    
089            log.debug("templateName is " + templateName);
090    
091            // Last element decides, which template Service to use...
092            TemplateEngineService tes = TurbineTemplate.getTemplateEngineService(templateName);
093    
094            if (tes == null)
095            {
096                return null;
097            }
098    
099            String defaultName =
100                TurbineTemplate.getDefaultLayoutTemplateName(templateName); // We're, after all, a Layout Template Mapper...
101    
102            // This is an optimization. If the name we're looking for is
103            // already the default name for the template, don't do a "first run"
104            // which looks for an exact match.
105            boolean firstRun = !templateName.equals(defaultName);
106    
107            for(;;)
108            {
109                String templatePackage = StringUtils.join(components.iterator(), String.valueOf(separator));
110    
111                log.debug("templatePackage is now: " + templatePackage);
112    
113                StringBuffer testName = new StringBuffer();
114    
115                if (!components.isEmpty())
116                {
117                    testName.append(templatePackage);
118                    testName.append(separator);
119                }
120    
121                testName.append((firstRun)
122                    ? templateName
123                    : defaultName);
124    
125                // But the Templating service must look for the name with prefix
126                StringBuffer templatePath = new StringBuffer();
127                if (StringUtils.isNotEmpty(prefix))
128                {
129                    templatePath.append(prefix);
130                    templatePath.append(separator);
131                }
132                templatePath.append(testName);
133    
134                log.debug("Looking for " + templatePath);
135    
136                if (tes.templateExists(templatePath.toString()))
137                {
138                    log.debug("Found it, returning " + testName);
139                    return testName.toString();
140                }
141    
142                if (firstRun)
143                {
144                    firstRun = false;
145                }
146                else
147                {
148                    // We're no longer on the first Run (so we
149                    // already tested the "Default" template)
150                    // and the package is empty (we've hit the
151                    // root. So we now break the endless loop.
152                    if (components.isEmpty())
153                    {
154                        break; // for(;;)
155                    }
156                    // We still have components. Remove the
157                    // last one and go through the loop again.
158                    components.remove(componentSize--);
159                }
160            }
161    
162            log.debug("Returning default");
163            return getDefaultName(template);
164        }
165    }