/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.wicket.resource;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import org.apache.wicket.Application;
import org.apache.wicket.settings.IResourceSettings;
import org.apache.wicket.util.listener.IChangeListener;
import org.apache.wicket.util.resource.IResourceStream;
import org.apache.wicket.util.resource.ResourceStreamNotFoundException;
import org.apache.wicket.util.resource.locator.IResourceStreamLocator;
import org.apache.wicket.util.value.ValueMap;
import org.apache.wicket.util.watch.IModificationWatcher;
import org.apache.wicket.util.watch.ModificationWatcher;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Default implementation of {@link IPropertiesFactory} which uses the
* {@link IResourceStreamLocator} as defined by {@link IResourceSettings#getResourceStreamLocator()}
* to load the {@link Properties} objects. Depending on the settings, it will assign
* {@link ModificationWatcher}s to the loaded resources to support reloading.
*
* @see org.apache.wicket.settings.IResourceSettings#getPropertiesFactory()
*
* @author Juergen Donnerstag
*/
public class PropertiesFactory implements IPropertiesFactory
{
/** Log. */
private static final Logger log = LoggerFactory.getLogger(PropertiesFactory.class);
/** Listeners will be invoked after changes to property file have been detected */
private final List<IPropertiesChangeListener> afterReloadListeners = new ArrayList<IPropertiesChangeListener>();
/** Cache for all property files loaded */
private final Map<String, Properties> propertiesCache = new ConcurrentHashMap<String, Properties>();
/** This is necessary since the ModificationWatcher runs in a separate thread */
private final Application application;
/** List of Properties Loader */
private final List<IPropertiesLoader> propertiesLoader;
/**
* Construct.
*
* @param application
* Application for this properties factory.
*/
public PropertiesFactory(final Application application)
{
this.application = application;
propertiesLoader = new ArrayList<IPropertiesLoader>();
propertiesLoader.add(new IsoPropertiesFilePropertiesLoader("properties"));
propertiesLoader.add(new UtfPropertiesFilePropertiesLoader("utf8.properties", "utf-8"));
propertiesLoader.add(new XmlFilePropertiesLoader("properties.xml"));
}
/**
* Gets the {@link List} of properties loader. You may add or remove properties loaders at your
* will.
*
* @return the {@link List} of properties loader
*/
public List<IPropertiesLoader> getPropertiesLoaders()
{
return propertiesLoader;
}
/**
* @see org.apache.wicket.resource.IPropertiesFactory#addListener(org.apache.wicket.resource.IPropertiesChangeListener)
*/
public void addListener(final IPropertiesChangeListener listener)
{
// Make sure listeners are added only once
if (afterReloadListeners.contains(listener) == false)
{
afterReloadListeners.add(listener);
}
}
/**
* @see org.apache.wicket.resource.IPropertiesFactory#clearCache()
*/
public final void clearCache()
{
propertiesCache.clear();
// clear the localizer cache as well
application.getResourceSettings().getLocalizer().clearCache();
}
/**
*
* @see org.apache.wicket.resource.IPropertiesFactory#load(java.lang.Class, java.lang.String)
*/
public Properties load(final Class<?> clazz, final String path)
{
// Check the cache
Properties properties = propertiesCache.get(path);
if (properties == null)
{
IResourceSettings resourceSettings = Application.get().getResourceSettings();
Iterator<IPropertiesLoader> iter = propertiesLoader.iterator();
while ((properties == null) && iter.hasNext())
{
IPropertiesLoader loader = iter.next();
String fullPath = path + loader.getFileExtension();
// If not in the cache than try to load properties
final IResourceStream resourceStream = resourceSettings.getResourceStreamLocator()
.locate(clazz, fullPath);
if (resourceStream == null)
{
continue;
}
// Watch file modifications
final IModificationWatcher watcher = resourceSettings.getResourceWatcher(true);
if (watcher != null)
{
addToWatcher(path, resourceStream, watcher);
}
ValueMap props = loadFromLoader(loader, resourceStream);
if (props != null)
{
properties = new Properties(path, props);
}
}
// Cache the lookup
if (properties == null)
{
// Could not locate properties, store a placeholder
propertiesCache.put(path, Properties.EMPTY_PROPERTIES);
}
else
{
propertiesCache.put(path, properties);
}
}
if (properties == Properties.EMPTY_PROPERTIES)
{
// Translate empty properties placeholder to null prior to returning
properties = null;
}
return properties;
}
/**
*
* @param loader
* @param resourceStream
* @return properties
*/
private ValueMap loadFromLoader(final IPropertiesLoader loader,
final IResourceStream resourceStream)
{
if (log.isInfoEnabled())
{
log.info("Loading properties files from " + resourceStream + " with loader " + loader);
}
BufferedInputStream in = null;
try
{
// Get the InputStream
in = new BufferedInputStream(resourceStream.getInputStream());
ValueMap data = loader.loadWicketProperties(in);
if (data == null)
{
java.util.Properties props = loader.loadJavaProperties(in);
if (props != null)
{
// Copy the properties into the ValueMap
data = new ValueMap();
Enumeration<?> enumeration = props.propertyNames();
while (enumeration.hasMoreElements())
{
String property = (String)enumeration.nextElement();
data.put(property, props.getProperty(property));
}
}
}
return data;
}
catch (ResourceStreamNotFoundException e)
{
log.warn("Unable to find resource " + resourceStream, e);
}
catch (IOException e)
{
log.warn("Unable to find resource " + resourceStream, e);
}
finally
{
if (in != null)
{
try
{
in.close();
}
catch (IOException ex)
{
// ignore
}
}
try
{
resourceStream.close();
}
catch (IOException ex)
{
// ignore
}
}
return null;
}
/**
* Add the resource stream to the file being watched
*
* @param path
* @param resourceStream
* @param watcher
*/
private void addToWatcher(final String path, final IResourceStream resourceStream,
final IModificationWatcher watcher)
{
watcher.add(resourceStream, new IChangeListener()
{
public void onChange()
{
log.info("A properties files has changed. Removing all entries " +
"from the cache. Resource: " + resourceStream);
// Clear the whole cache as associated localized files may
// be affected and may need reloading as well.
clearCache();
// Inform all listeners
Iterator<IPropertiesChangeListener> iter = afterReloadListeners.iterator();
while (iter.hasNext())
{
IPropertiesChangeListener listener = iter.next();
try
{
listener.propertiesChanged(path);
}
catch (Throwable ex)
{
PropertiesFactory.log.error("PropertiesReloadListener has thrown an exception: " +
ex.getMessage());
}
}
}
});
}
/**
* For subclasses to get access to the cache
*
* @return Map
*/
protected final Map<String, Properties> getCache()
{
return propertiesCache;
}
}