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/*
* 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.tuscany.sca.core;
import static org.apache.tuscany.sca.extensibility.ServiceHelper.newInstance;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.tuscany.sca.extensibility.ServiceDeclaration;
/**
* Default implementation of an extension point to hold Tuscany module activators.
*
* @version $Rev$ $Date$
*/
public class DefaultModuleActivatorExtensionPoint implements ModuleActivatorExtensionPoint {
private final static Logger logger = Logger.getLogger(DefaultModuleActivatorExtensionPoint.class.getName());
private List<ModuleActivator> activators = new ArrayList<ModuleActivator>();
private boolean loadedActivators;
private boolean started;
private ExtensionPointRegistry registry;
/**
* Constructs a new extension point.
*/
public DefaultModuleActivatorExtensionPoint(ExtensionPointRegistry registry) {
this.registry = registry;
}
public void addModuleActivator(ModuleActivator activator) {
activators.add(activator);
}
public List<ModuleActivator> getModuleActivators() {
loadModuleActivators();
return activators;
}
public void removeModuleActivator(ModuleActivator activator) {
if (activators.remove(activator)) {
activator.stop();
}
}
/**
* Dynamically load module activators declared under META-INF/services
*/
private synchronized void loadModuleActivators() {
if (loadedActivators)
return;
// Get the activator service declarations
Collection<ServiceDeclaration> activatorDeclarations;
try {
// Load the module activators by ranking
activatorDeclarations = registry.getServiceDiscovery().getServiceDeclarations(ModuleActivator.class.getName(), true);
} catch (IOException e) {
throw new IllegalStateException(e);
}
// Load and instantiate module activators
for (ServiceDeclaration activatorDeclaration : activatorDeclarations) {
if (logger.isLoggable(Level.FINE)) {
logger.fine("Loading " + activatorDeclaration.getClassName());
}
ModuleActivator activator = null;
try {
Class<ModuleActivator> activatorClass = (Class<ModuleActivator>)activatorDeclaration.loadClass();
try {
activator = newInstance(activatorClass, ExtensionPointRegistry.class, registry);
} catch (NoSuchMethodException e) {
try {
activator =
newInstance(activatorClass,
new Class<?>[] {ExtensionPointRegistry.class, Map.class},
registry,
activatorDeclaration.getAttributes());
} catch (NoSuchMethodException e1) {
activator = newInstance(activatorClass);
}
}
} catch (Throwable e) {
String optional = activatorDeclaration.getAttributes().get("optional");
if ("true".equalsIgnoreCase(optional)) {
// If the optional flag is true, just log the error
logger.log(Level.SEVERE, e.getMessage(), e);
continue;
} else {
throw new IllegalArgumentException(e);
}
}
addModuleActivator(activator);
}
loadedActivators = true;
}
public void start() {
if (started) {
return;
}
getModuleActivators();
for (ModuleActivator activator : activators) {
try {
activator.start();
} catch (Throwable e) {
// Ignore the failing module for now
logger.log(Level.SEVERE, e.getMessage(), e);
}
}
started = true;
}
public void stop() {
if (!started) {
return;
}
for (int i = activators.size() - 1; i >= 0; i--) {
try {
activators.get(i).stop();
} catch (Throwable e) {
// Ignore the failing module for now
logger.log(Level.SEVERE, e.getMessage(), e);
}
}
started = false;
}
}
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