001 // Copyright 2007, 2008, 2010 The Apache Software Foundation
002 //
003 // Licensed under the Apache License, Version 2.0 (the "License");
004 // you may not use this file except in compliance with the License.
005 // You may obtain a copy of the License at
006 //
007 // http://www.apache.org/licenses/LICENSE-2.0
008 //
009 // Unless required by applicable law or agreed to in writing, software
010 // distributed under the License is distributed on an "AS IS" BASIS,
011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012 // See the License for the specific language governing permissions and
013 // limitations under the License.
014
015 package org.apache.tapestry5.internal.services;
016
017 import org.apache.tapestry5.ComponentResources;
018 import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
019 import org.apache.tapestry5.ioc.services.SymbolSource;
020 import org.apache.tapestry5.ioc.services.TypeCoercer;
021 import org.apache.tapestry5.services.InvalidationListener;
022 import org.apache.tapestry5.services.MetaDataLocator;
023
024 import java.util.Map;
025
026 public class MetaDataLocatorImpl implements MetaDataLocator, InvalidationListener
027 {
028 private final SymbolSource symbolSource;
029
030 private final TypeCoercer typeCoercer;
031
032 private final ComponentModelSource modelSource;
033
034 private final Map<String, Map<String, String>> defaultsByFolder = CollectionFactory
035 .newCaseInsensitiveMap();
036
037 private final Map<String, String> cache = CollectionFactory.newConcurrentMap();
038
039 private interface ValueLocator
040 {
041 String valueForKey(String key);
042 }
043
044 public MetaDataLocatorImpl(SymbolSource symbolSource, TypeCoercer typeCoercer,
045 ComponentModelSource modelSource, Map<String, String> configuration)
046 {
047 this.symbolSource = symbolSource;
048 this.typeCoercer = typeCoercer;
049 this.modelSource = modelSource;
050
051 loadDefaults(configuration);
052 }
053
054 public void objectWasInvalidated()
055 {
056 cache.clear();
057 }
058
059 private void loadDefaults(Map<String, String> configuration)
060 {
061 for (Map.Entry<String, String> e : configuration.entrySet())
062 {
063 String key = e.getKey();
064
065 int colonx = key.indexOf(':');
066
067 String folderKey = colonx < 0 ? "" : key.substring(0, colonx);
068
069 Map<String, String> forFolder = defaultsByFolder.get(folderKey);
070
071 if (forFolder == null)
072 {
073 forFolder = CollectionFactory.newCaseInsensitiveMap();
074 defaultsByFolder.put(folderKey, forFolder);
075 }
076
077 String defaultKey = colonx < 0 ? key : key.substring(colonx + 1);
078
079 forFolder.put(defaultKey, e.getValue());
080 }
081 }
082
083 public <T> T findMeta(String key, final ComponentResources resources, Class<T> expectedType)
084 {
085 String value = getSymbolExpandedValueFromCache(key, resources.getCompleteId() + "/" + key,
086 new ValueLocator()
087 {
088 public String valueForKey(String key)
089 {
090 return locate(key, resources);
091 }
092 });
093
094 return typeCoercer.coerce(value, expectedType);
095 }
096
097 public <T> T findMeta(String key, final String pageName, Class<T> expectedType)
098 {
099 String value = getSymbolExpandedValueFromCache(key, pageName + "/" + key,
100 new ValueLocator()
101 {
102 public String valueForKey(String key)
103 {
104 String result = modelSource.getPageModel(pageName).getMeta(key);
105
106 return result != null ? result : locateInDefaults(key, pageName);
107 }
108 });
109
110 return typeCoercer.coerce(value, expectedType);
111 }
112
113 private String getSymbolExpandedValueFromCache(String key, String cacheKey,
114 ValueLocator valueLocator)
115 {
116 if (cache.containsKey(cacheKey))
117 return cache.get(cacheKey);
118
119 String value = valueLocator.valueForKey(key);
120
121 if (value == null)
122 {
123 value = symbolSource.valueForSymbol(key);
124 }
125 else
126 {
127 value = symbolSource.expandSymbols(value);
128 }
129
130 cache.put(cacheKey, value);
131
132 return value;
133 }
134
135 private String locate(String key, ComponentResources resources)
136 {
137 ComponentResources cursor = resources;
138
139 while (true)
140 {
141 String value = cursor.getComponentModel().getMeta(key);
142
143 if (value != null)
144 return value;
145
146 ComponentResources next = cursor.getContainerResources();
147
148 if (next == null)
149 return locateInDefaults(key, cursor.getPageName());
150
151 cursor = next;
152 }
153 }
154
155 private String locateInDefaults(String key, String pageName)
156 {
157
158 // We're going to peel this apart, slash by slash. Thus for
159 // "mylib/myfolder/mysubfolder/MyPage" we'll be checking: "mylib/myfolder/mysubfolder",
160 // then "mylib/myfolder", then "mylib", then "".
161
162 String path = pageName;
163
164 while (true)
165 {
166 int lastSlashx = path.lastIndexOf('/');
167
168 String folderKey = lastSlashx < 0 ? "" : path.substring(0, lastSlashx);
169
170 Map<String, String> forFolder = defaultsByFolder.get(folderKey);
171
172 if (forFolder != null && forFolder.containsKey(key))
173 return forFolder.get(key);
174
175 if (lastSlashx < 0)
176 break;
177
178 path = path.substring(0, lastSlashx);
179 }
180
181 // Perhaps from here into the symbol sources? That may come later.
182
183 return null;
184 }
185 }