/**
* 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.camel.script.osgi;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.lang.reflect.Method;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import org.apache.camel.impl.osgi.tracker.BundleTracker;
import org.apache.camel.impl.osgi.tracker.BundleTrackerCustomizer;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleEvent;
import org.osgi.framework.InvalidSyntaxException;
import org.osgi.framework.ServiceReference;
import org.osgi.framework.ServiceRegistration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
public class Activator implements BundleActivator, BundleTrackerCustomizer {
public static final String META_INF_SERVICES_DIR = "META-INF/services";
public static final String SCRIPT_ENGINE_SERVICE_FILE = "javax.script.ScriptEngineFactory";
private static final transient Logger LOG = LoggerFactory.getLogger(Activator.class);
private static BundleContext context;
private BundleTracker tracker;
private Map<Long, List<BundleScriptEngineResolver>> resolvers
= new ConcurrentHashMap<Long, List<BundleScriptEngineResolver>>();
public static BundleContext getBundleContext() {
return context;
}
public void start(BundleContext context) throws Exception {
Activator.context = context;
LOG.info("Camel-Script activator starting");
tracker = new BundleTracker(context, Bundle.ACTIVE, this);
tracker.open();
LOG.info("Camel-Script activator started");
}
public void stop(BundleContext context) throws Exception {
LOG.info("Camel-Script activator stopping");
tracker.close();
LOG.info("Camel-Script activator stopped");
Activator.context = null;
}
public Object addingBundle(Bundle bundle, BundleEvent event) {
List<BundleScriptEngineResolver> r = new ArrayList<BundleScriptEngineResolver>();
registerScriptEngines(bundle, r);
for (BundleScriptEngineResolver service : r) {
service.register();
}
resolvers.put(bundle.getBundleId(), r);
return bundle;
}
public void modifiedBundle(Bundle bundle, BundleEvent event, Object object) {
}
public void removedBundle(Bundle bundle, BundleEvent event, Object object) {
LOG.debug("Bundle stopped: {}", bundle.getSymbolicName());
List<BundleScriptEngineResolver> r = resolvers.remove(bundle.getBundleId());
if (r != null) {
for (BundleScriptEngineResolver service : r) {
service.unregister();
}
}
}
public static ScriptEngine resolveScriptEngine(String scriptEngineName) throws InvalidSyntaxException {
ServiceReference[] refs = context.getServiceReferences(ScriptEngineResolver.class.getName(), null);
if (refs == null) {
LOG.info("No OSGi script engine resolvers available!");
return null;
}
LOG.debug("Found " + refs.length + " OSGi ScriptEngineResolver services");
for (ServiceReference ref : refs) {
ScriptEngineResolver resolver = (ScriptEngineResolver) context.getService(ref);
ScriptEngine engine = resolver.resolveScriptEngine(scriptEngineName);
context.ungetService(ref);
LOG.debug("OSGi resolver " + resolver + " produced " + scriptEngineName + " engine " + engine);
if (engine != null) {
return engine;
}
}
return null;
}
protected void registerScriptEngines(Bundle bundle, List<BundleScriptEngineResolver> resolvers) {
URL configURL = null;
for (Enumeration e = bundle.findEntries(META_INF_SERVICES_DIR, SCRIPT_ENGINE_SERVICE_FILE, false); e != null && e.hasMoreElements();) {
configURL = (URL) e.nextElement();
}
if (configURL != null) {
LOG.info("Found ScriptEngineFactory in " + bundle.getSymbolicName());
resolvers.add(new BundleScriptEngineResolver(bundle, configURL));
}
}
public static interface ScriptEngineResolver {
ScriptEngine resolveScriptEngine(String name);
}
protected static class BundleScriptEngineResolver implements ScriptEngineResolver {
protected final Bundle bundle;
private ServiceRegistration reg;
private final URL configFile;
public BundleScriptEngineResolver(Bundle bundle, URL configFile) {
this.bundle = bundle;
this.configFile = configFile;
}
public void register() {
reg = bundle.getBundleContext().registerService(ScriptEngineResolver.class.getName(),
this, null);
}
public void unregister() {
reg.unregister();
}
public ScriptEngine resolveScriptEngine(String name) {
try {
BufferedReader in = new BufferedReader(new InputStreamReader(configFile.openStream()));
String className = in.readLine();
in.close();
Class cls = bundle.loadClass(className);
if (!ScriptEngineFactory.class.isAssignableFrom(cls)) {
throw new IllegalStateException("Invalid ScriptEngineFactory: " + cls.getName());
}
ScriptEngineFactory factory = (ScriptEngineFactory) cls.newInstance();
List<String> names = factory.getNames();
for (String test : names) {
if (test.equals(name)) {
ClassLoader old = Thread.currentThread().getContextClassLoader();
ScriptEngine engine;
try {
// JRuby seems to require the correct TCCL to call getScriptEngine
Thread.currentThread().setContextClassLoader(factory.getClass().getClassLoader());
engine = factory.getScriptEngine();
} finally {
Thread.currentThread().setContextClassLoader(old);
}
LOG.trace("Resolved ScriptEngineFactory: {} for expected name: {}", engine, name);
return engine;
}
}
LOG.debug("ScriptEngineFactory: {} does not match expected name: {}", factory.getEngineName(), name);
return null;
} catch (Exception e) {
LOG.warn("Cannot create ScriptEngineFactory: " + e.getClass().getName(), e);
return null;
}
}
@Override
public String toString() {
return "OSGi script engine resolver for " + bundle.getSymbolicName();
}
}
}