| /* |
| * 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.qi4j.runtime.service; |
| |
| import java.lang.reflect.Method; |
| import org.qi4j.api.activation.Activation; |
| import org.qi4j.api.activation.ActivationEventListener; |
| import org.qi4j.api.activation.ActivationException; |
| import org.qi4j.api.activation.PassivationException; |
| import org.qi4j.api.composite.CompositeDescriptor; |
| import org.qi4j.api.composite.CompositeInstance; |
| import org.qi4j.api.property.StateHolder; |
| import org.qi4j.api.service.ServiceDescriptor; |
| import org.qi4j.api.service.ServiceImporterException; |
| import org.qi4j.api.service.ServiceReference; |
| import org.qi4j.api.service.ServiceUnavailableException; |
| import org.qi4j.api.structure.Module; |
| import org.qi4j.runtime.activation.ActivationDelegate; |
| import org.qi4j.runtime.structure.ModuleInstance; |
| |
| /** |
| * Implementation of ServiceReference. |
| * <p> |
| * This manages the actual instance of the service and implements the service Activation. |
| * </p> |
| * <p> |
| * Whenever the service is requested a proxy is returned which points to this class. This means |
| * that the instance can be passivated even though a client is holding on to a service proxy. |
| * </p> |
| * @param <T> Service Type |
| */ |
| public final class ServiceReferenceInstance<T> |
| implements ServiceReference<T>, Activation |
| { |
| private volatile ServiceInstance instance; |
| private final T serviceProxy; |
| private final ModuleInstance module; |
| private final ServiceModel serviceModel; |
| private final ActivationDelegate activation = new ActivationDelegate( this ); |
| private boolean active = false; |
| |
| public ServiceReferenceInstance( ServiceModel serviceModel, ModuleInstance module ) |
| { |
| this.module = module; |
| this.serviceModel = serviceModel; |
| |
| serviceProxy = newProxy(); |
| } |
| |
| @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 serviceProxy; |
| } |
| |
| @Override |
| public boolean isActive() |
| { |
| return active; |
| } |
| |
| @Override |
| public boolean isAvailable() |
| { |
| return getInstance().isAvailable(); |
| } |
| |
| public Module module() |
| { |
| return module; |
| } |
| |
| @Override |
| public void activate() |
| throws ActivationException |
| { |
| if( serviceModel.isInstantiateOnStartup() ) |
| { |
| getInstance(); |
| } |
| } |
| |
| @Override |
| public void passivate() |
| throws PassivationException |
| { |
| if( instance != null ) |
| { |
| try { |
| activation.passivate( new Runnable() |
| { |
| @Override |
| public void run() |
| { |
| active = false; |
| } |
| } ); |
| } finally { |
| instance = null; |
| active = false; |
| } |
| } |
| } |
| |
| private ServiceInstance getInstance() |
| throws ServiceImporterException |
| { |
| // DCL that works with Java 1.5 volatile semantics |
| if( instance == null ) |
| { |
| synchronized( this ) |
| { |
| if( instance == null ) |
| { |
| instance = serviceModel.newInstance( module ); |
| |
| try |
| { |
| activation.activate( serviceModel.newActivatorsInstance( module ), instance, new Runnable() |
| { |
| @Override |
| public void run() |
| { |
| active = true; |
| } |
| } ); |
| } |
| catch( Exception e ) |
| { |
| instance = null; |
| throw new ServiceUnavailableException( "Could not activate service " + serviceModel.identity(), e ); |
| } |
| } |
| } |
| } |
| |
| return instance; |
| } |
| |
| @Override |
| public String toString() |
| { |
| return serviceModel.identity() + "(active=" + isActive() + ",module='" + module.name() + "')"; |
| } |
| |
| @SuppressWarnings( "unchecked" ) |
| public T newProxy() |
| { |
| return (T) serviceModel.newProxy( new ServiceReferenceInstance.ServiceInvocationHandler() ); |
| } |
| |
| public ServiceDescriptor serviceDescriptor() |
| { |
| return serviceModel; |
| } |
| |
| public final class ServiceInvocationHandler |
| implements CompositeInstance |
| { |
| @Override |
| @SuppressWarnings( "unchecked" ) |
| public <T> T proxy() |
| { |
| return (T) ServiceReferenceInstance.this.get(); |
| } |
| |
| @Override |
| public <T> T newProxy( Class<T> mixinType ) |
| throws IllegalArgumentException |
| { |
| return getInstance().newProxy( mixinType ); |
| } |
| |
| @Override |
| public <T> T metaInfo( Class<T> infoType ) |
| { |
| return ServiceReferenceInstance.this.metaInfo( infoType ); |
| } |
| |
| @Override |
| public Iterable<Class<?>> types() |
| { |
| return ServiceReferenceInstance.this.types(); |
| } |
| |
| @Override |
| public CompositeDescriptor descriptor() |
| { |
| return ServiceReferenceInstance.this.serviceDescriptor(); |
| } |
| |
| @Override |
| public Object invokeComposite( Method method, Object[] args ) |
| throws Throwable |
| { |
| return getInstance().invokeComposite( method, args ); |
| } |
| |
| @Override |
| public StateHolder state() |
| { |
| return getInstance().state(); |
| } |
| |
| @Override |
| public Object invoke( Object object, Method method, Object[] objects ) |
| throws Throwable |
| { |
| if( method.getDeclaringClass().equals( Object.class ) ) |
| { |
| switch( method.getName() ) |
| { |
| case "toString": |
| return serviceModel.toString(); |
| case "equals": |
| return objects[0] == object; |
| case "hashCode": |
| return serviceModel.toString().hashCode(); |
| } |
| } |
| |
| ServiceInstance instance = getInstance(); |
| |
| /* |
| if (!instance.isAvailable()) |
| { |
| throw new ServiceUnavailableException("Service is currently not available"); |
| } |
| |
| */ |
| return instance.invoke( object, method, objects ); |
| } |
| |
| @Override |
| public String toString() |
| { |
| return serviceModel.toString(); |
| } |
| |
| @Override |
| public Module module() |
| { |
| return module; |
| } |
| } |
| |
| @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 |
| @SuppressWarnings( "raw" ) |
| 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() ); |
| } |
| |
| } |