| /* |
| * 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.qi4j.library.osgi; |
| |
| import java.lang.reflect.InvocationHandler; |
| import java.lang.reflect.Method; |
| import java.lang.reflect.Proxy; |
| import org.osgi.framework.BundleContext; |
| import org.osgi.framework.ServiceReference; |
| import org.osgi.util.tracker.ServiceTracker; |
| import org.qi4j.api.service.ImportedServiceDescriptor; |
| import org.qi4j.api.service.ServiceImporter; |
| import org.qi4j.api.service.ServiceImporterException; |
| import org.qi4j.api.service.ServiceUnavailableException; |
| |
| /** |
| * Import OSGi services in a Zest Module. |
| */ |
| public class OSGiServiceImporter |
| implements ServiceImporter |
| { |
| |
| @Override |
| public Object importService( ImportedServiceDescriptor serviceDescriptor ) |
| throws ServiceImporterException |
| { |
| OSGiImportInfo info = serviceDescriptor.metaInfo( OSGiImportInfo.class ); |
| BundleContext context = info.bundleContext(); |
| ServiceTrackerHandler handler = new ServiceTrackerHandler( context, serviceDescriptor.type() ); |
| handler.open(); |
| return Proxy.newProxyInstance( serviceDescriptor.type().getClassLoader(), info.interfaces(), handler ); |
| } |
| |
| @Override |
| public boolean isAvailable( Object instance ) |
| { |
| ServiceTrackerHandler handler = (ServiceTrackerHandler) Proxy.getInvocationHandler( instance ); |
| return handler.isAvailable(); |
| } |
| |
| public static class ServiceTrackerHandler |
| extends ServiceTracker |
| implements InvocationHandler |
| { |
| |
| private volatile Object service; |
| private Class typeToImport; |
| |
| public ServiceTrackerHandler( BundleContext context, Class typeToImport ) |
| { |
| super( context, typeToImport.getName(), null ); |
| this.typeToImport = typeToImport; |
| } |
| |
| @Override |
| public Object invoke( Object proxy, Method method, Object[] args ) |
| throws Throwable |
| { |
| Object temporary; |
| synchronized( this ) |
| { |
| if( service == null ) |
| { |
| wait( 5000 ); // Max wait 5 seconds. |
| if( service == null ) |
| { |
| throw new ServiceUnavailableException( |
| "The OSGi service is currently not available: " + typeToImport.getName() ); |
| } |
| } |
| temporary = service; |
| } |
| return method.invoke( temporary, args ); |
| } |
| |
| @Override |
| public Object addingService( ServiceReference reference ) |
| { |
| synchronized( this ) |
| { |
| service = super.addingService( reference ); |
| notifyAll(); |
| return service; |
| } |
| } |
| |
| @Override |
| public void removedService( ServiceReference reference, Object service ) |
| { |
| synchronized( this ) |
| { |
| super.removedService( reference, service ); |
| notifyAll(); |
| this.service = null; |
| } |
| } |
| |
| public boolean isAvailable() |
| { |
| return service != null; |
| } |
| |
| } |
| |
| } |