/*
* 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.wookie.feature;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.apache.log4j.Logger;
import org.apache.wookie.beans.IServerFeature;
import org.apache.wookie.beans.util.IPersistenceManager;
import org.apache.wookie.beans.util.PersistenceCommitException;
import org.apache.wookie.beans.util.PersistenceManagerFactory;
import org.apache.wookie.w3c.util.IRIValidator;
import java.util.Iterator;
/**
* Loads installed features when server is initialized
*
*/
public class FeatureLoader {
static Logger _logger = Logger.getLogger(FeatureLoader.class.getName());
/**
* Loads features based on the properties configuration supplied
* @param config
*/
@SuppressWarnings("unchecked")
public static void loadFeatures(PropertiesConfiguration config){
IPersistenceManager persistenceManager = PersistenceManagerFactory.getPersistenceManager();
persistenceManager.begin();
// Remove existing features
for (IServerFeature sf: persistenceManager.findAll(IServerFeature.class)){
persistenceManager.delete(sf);
}
// Add features in properties configuration
Iterator i = config.getKeys();
while (i.hasNext()){
String klass = (String) i.next();
String name = config.getString(klass);
try {
IServerFeature sf = createFeature(name, klass);
// Only install it if there isn't an existing
// feature with the same name
if (persistenceManager.findServerFeatureByName(name) == null){
persistenceManager.save(sf);
_logger.info("Installed feature:"+name);
} else {
_logger.error("Error installing feature: "+name+" was already installed");
}
} catch (Exception e) {
_logger.error("Error installing feature:"+e.getMessage());
}
}
try
{
persistenceManager.commit();
}
catch (PersistenceCommitException pce)
{
throw new RuntimeException("Feature loading exception: "+pce, pce);
}
PersistenceManagerFactory.closePersistenceManager();
}
/**
* Validates a feature for the supplied parameters, or throws
* an exception if the feature specified is not a valid.
* @param name the name of the feature, which must be a valid IRI
* @param klass the Class name of the feature, which must implement the IFeature interface
*/
@SuppressWarnings("unchecked")
public static void validateFeature(String name, String klass) throws Exception{
// Are required parameters missing?
if (name == null || klass == null){
throw new Exception("Invalid feature");
}
// Does the class exist?
Class theClass;
try {
theClass = Class.forName(klass);
} catch (Exception e) {
throw new Exception("Invalid feature: class not found");
}
// Does the class implement IFeature?
boolean implementsFeature = false;
Class[] interfaces = theClass.getInterfaces();
if (interfaces != null) {
if (interfaces.length > 0){
if (interfaces[0].getName().equals("org.apache.wookie.feature.IFeature")) implementsFeature = true;
}
}
if (!implementsFeature) throw new Exception("Invalid feature: class is not a Feature class");
// Does the feature name match that in the class?
if (!((IFeature) theClass.newInstance()).getName().equals(name)) throw new Exception("Invalid feature: feature name supplied and name in the class do not match");;
// Is the feature name a valid IRI?
if (!IRIValidator.isValidIRI(name)){
throw new Exception("Invalid feature: name is not a valid IRI");
}
}
/**
* Returns a valid ServerFeature for the supplied parameters, or throws
* an exception if the feature specified is not a valid ServerFeature.
* @param name the name of the feature, which must be a valid IRI
* @param klass the Class name of the feature, which must implement the IFeature interface
*/
public static IServerFeature createFeature(String name, String klass) throws Exception{
// validate feature
validateFeature(name, klass);
// All is well, create the SF and return it
IPersistenceManager persistenceManager = PersistenceManagerFactory.getPersistenceManager();
IServerFeature sf = persistenceManager.newInstance(IServerFeature.class);
sf.setClassName(klass);
sf.setFeatureName(name);
return sf;
}
}