| /* |
| * Copyright (c) 2008-2011, Rickard Öberg. All Rights Reserved. |
| * Copyright (c) 2008-2013, Niclas Hedhman. All Rights Reserved. |
| * Copyright (c) 2012-2014, Paul Merlin. All Rights Reserved. |
| * |
| * 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.zest.runtime.service; |
| |
| import org.apache.zest.api.activation.Activation; |
| import org.apache.zest.api.activation.ActivationEventListener; |
| import org.apache.zest.api.activation.ActivationException; |
| import org.apache.zest.api.activation.PassivationException; |
| import org.apache.zest.api.service.ServiceImporterException; |
| import org.apache.zest.api.service.ServiceReference; |
| import org.apache.zest.api.service.ServiceUnavailableException; |
| import org.apache.zest.api.structure.Module; |
| import org.apache.zest.runtime.activation.ActivationDelegate; |
| |
| /** |
| * Implementation of ServiceReference. This manages the reference to the imported service. |
| * <p> |
| * Whenever the service is requested it is returned directly to the client. That means that |
| * to handle service passivation and unavailability correctly, any proxying must be done in the |
| * service importer. |
| * </p> |
| * @param <T> Service Type |
| */ |
| public final class ImportedServiceReferenceInstance<T> |
| implements ServiceReference<T>, Activation |
| { |
| private volatile ImportedServiceInstance<T> serviceInstance; |
| private T instance; |
| private final Module module; |
| private final ImportedServiceModel serviceModel; |
| private final ActivationDelegate activation = new ActivationDelegate( this ); |
| private boolean active = false; |
| |
| public ImportedServiceReferenceInstance( ImportedServiceModel serviceModel, Module module ) |
| { |
| this.module = module; |
| this.serviceModel = serviceModel; |
| } |
| |
| @Override |
| public String identity() |
| { |
| return serviceModel.identity(); |
| } |
| |
| @Override |
| public Iterable<Class<?>> types() |
| { |
| return serviceModel.types(); |
| } |
| |
| @Override |
| public <T> T metaInfo( Class<T> infoType ) |
| { |
| return serviceModel.metaInfo( infoType ); |
| } |
| |
| @Override |
| public synchronized T get() |
| { |
| return getInstance(); |
| } |
| |
| public ImportedServiceModel serviceDescriptor() |
| { |
| return serviceModel; |
| } |
| |
| @Override |
| public void activate() |
| throws ActivationException |
| { |
| if( serviceModel.isImportOnStartup() ) |
| { |
| getInstance(); |
| } |
| } |
| |
| @Override |
| public void passivate() |
| throws PassivationException |
| { |
| if( serviceInstance != null ) |
| { |
| try |
| { |
| activation.passivate( new Runnable() |
| { |
| @Override |
| public void run() |
| { |
| active = false; |
| } |
| } ); |
| } |
| finally |
| { |
| serviceInstance = null; |
| active = false; |
| } |
| } |
| } |
| |
| @Override |
| public boolean isActive() |
| { |
| return active; |
| } |
| |
| @Override |
| public boolean isAvailable() |
| { |
| try |
| { |
| getInstance(); |
| return serviceInstance.isAvailable(); |
| } |
| catch( ServiceImporterException ex ) |
| { |
| return false; |
| } |
| } |
| |
| public Module module() |
| { |
| return module; |
| } |
| |
| private T getInstance() |
| throws ServiceImporterException |
| { |
| // DCL that works with Java 1.5 volatile semantics |
| if( serviceInstance == null ) |
| { |
| synchronized( this ) |
| { |
| if( serviceInstance == null ) |
| { |
| serviceInstance = serviceModel.<T>importInstance( module ); |
| instance = serviceInstance.instance(); |
| |
| try |
| { |
| activation.activate( serviceModel.newActivatorsInstance( module ), serviceInstance, new Runnable() |
| { |
| @Override |
| public void run() |
| { |
| active = true; |
| } |
| } ); |
| } |
| catch( Exception e ) |
| { |
| serviceInstance = null; |
| throw new ServiceUnavailableException( "Could not activate service " + serviceModel.identity(), e ); |
| } |
| } |
| } |
| } |
| |
| return instance; |
| } |
| |
| @Override |
| public String toString() |
| { |
| return serviceModel.identity() + ", active=" + isActive() + ", module='" + serviceModel.moduleName() + "'"; |
| } |
| |
| @Override |
| public void registerActivationEventListener( ActivationEventListener listener ) |
| { |
| activation.registerActivationEventListener( listener ); |
| } |
| |
| @Override |
| public void deregisterActivationEventListener( ActivationEventListener listener ) |
| { |
| activation.deregisterActivationEventListener( listener ); |
| } |
| |
| @Override |
| public int hashCode() |
| { |
| return identity().hashCode(); |
| } |
| |
| @Override |
| public boolean equals( Object obj ) |
| { |
| if( obj == null ) |
| { |
| return false; |
| } |
| if( getClass() != obj.getClass() ) |
| { |
| return false; |
| } |
| final ServiceReference other = (ServiceReference) obj; |
| return identity().equals( other.identity() ); |
| } |
| } |