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Central module for Tapestry, containing interfaces to the Java
Servlet API and all core services and components.
// Copyright 2006, 2007, 2008, 2010 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.apache.tapestry5.internal.services;
import java.util.Collections;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import org.apache.tapestry5.internal.event.InvalidationEventHubImpl;
import org.apache.tapestry5.internal.util.MultiKey;
import org.apache.tapestry5.ioc.Messages;
import org.apache.tapestry5.ioc.Resource;
import org.apache.tapestry5.ioc.internal.util.CollectionFactory;
import org.apache.tapestry5.ioc.internal.util.LocalizedNameGenerator;
import org.apache.tapestry5.ioc.internal.util.URLChangeTracker;
import org.apache.tapestry5.services.messages.PropertiesFileParser;
/**
* A utility class that encapsulates all the logic for reading properties files and assembling {@link Messages} from
* them, in accordance with extension rules and locale. This represents code that was refactored out of
* {@link ComponentMessagesSourceImpl}. This class can be used as a base class, though the existing code base uses it as
* a
* utility. Composition trumps inheritance!
*
* The message catalog for a component is the combination of all appropriate properties files for the component, plus
* any keys inherited form base components and, ultimately, the application global message catalog. At some point we
* should add support for per-library message catalogs.
*
* Message catalogs are read using the UTF-8 character set. This is tricky in JDK 1.5; we read the file into memory then
* feed that bytestream to Properties.load().
*/
public class MessagesSourceImpl extends InvalidationEventHubImpl implements MessagesSource
{
private final URLChangeTracker tracker;
private final PropertiesFileParser propertiesFileParser;
/**
* Keyed on bundle id and locale.
*/
private final Map messagesByBundleIdAndLocale = CollectionFactory.newConcurrentMap();
/**
* Keyed on bundle id and locale, the cooked properties include properties inherited from less locale-specific
* properties files, or inherited from parent bundles.
*/
private final Map> cookedProperties = CollectionFactory.newConcurrentMap();
/**
* Raw properties represent just the properties read from a specific properties file, in isolation.
*/
private final Map> rawProperties = CollectionFactory.newConcurrentMap();
private final Map emptyMap = Collections.emptyMap();
public MessagesSourceImpl(URLChangeTracker tracker, PropertiesFileParser propertiesFileParser)
{
this.tracker = tracker;
this.propertiesFileParser = propertiesFileParser;
}
public void checkForUpdates()
{
if (tracker.containsChanges())
{
messagesByBundleIdAndLocale.clear();
cookedProperties.clear();
rawProperties.clear();
tracker.clear();
fireInvalidationEvent();
}
}
public Messages getMessages(MessagesBundle bundle, Locale locale)
{
MultiKey key = new MultiKey(bundle.getId(), locale);
Messages result = messagesByBundleIdAndLocale.get(key);
if (result == null)
{
result = buildMessages(bundle, locale);
messagesByBundleIdAndLocale.put(key, result);
}
return result;
}
private Messages buildMessages(MessagesBundle bundle, Locale locale)
{
Map properties = findBundleProperties(bundle, locale);
return new MapMessages(locale, properties);
}
/**
* Assembles a set of properties appropriate for the bundle in question, and the desired locale. The properties
* reflect the properties of the bundles' parent (if any) for the locale, overalyed with any properties defined for
* this bundle and its locale.
*/
private Map findBundleProperties(MessagesBundle bundle, Locale locale)
{
if (bundle == null)
return emptyMap;
MultiKey key = new MultiKey(bundle.getId(), locale);
Map existing = cookedProperties.get(key);
if (existing != null)
return existing;
// What would be cool is if we could maintain a cache of bundle id + locale -->
// Resource. That would optimize quite a bit of this; may need to use an alternative to
// LocalizedNameGenerator.
Resource propertiesResource = bundle.getBaseResource().withExtension("properties");
List localizations = CollectionFactory.newList();
for (String localizedFile : new LocalizedNameGenerator(propertiesResource.getFile(), locale))
{
Resource localized = propertiesResource.forFile(localizedFile);
localizations.add(localized);
}
// We need them in least-specific to most-specific order, the opposite
// of how the LocalizedNameGenerator provides them.
Collections.reverse(localizations);
// Localizations are now in least-specific to most-specific order.
Map previous = findBundleProperties(bundle.getParent(), locale);
for (Resource localization : localizations)
{
Map rawProperties = getRawProperties(localization);
// Woould be nice to write into the cookedProperties cache here,
// but we can't because we don't know the locale part of the MultiKey.
previous = extend(previous, rawProperties);
}
cookedProperties.put(key, previous);
return previous;
}
/**
* Returns a new map consisting of all the properties in previous overlayed with all the properties in
* rawProperties. If rawProperties is empty, returns just the base map.
*/
private Map extend(Map base, Map rawProperties)
{
if (rawProperties.isEmpty())
return base;
// Make a copy of the base Map
Map result = CollectionFactory.newCaseInsensitiveMap(base);
// Add or overwrite properties to the copy
result.putAll(rawProperties);
return result;
}
private Map getRawProperties(Resource localization)
{
Map result = rawProperties.get(localization);
if (result == null)
{
result = readProperties(localization);
rawProperties.put(localization, result);
}
return result;
}
/**
* Creates and returns a new map that contains properties read from the properties file.
*/
private Map readProperties(Resource resource)
{
if (!resource.exists())
return emptyMap;
tracker.add(resource.toURL());
try
{
return propertiesFileParser.parsePropertiesFile(resource);
}
catch (Exception ex)
{
throw new RuntimeException(ServicesMessages.failureReadingMessages(resource, ex), ex);
}
}
}