001/*
002 * Copyright 2002-2012 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.remoting.rmi;
018
019import org.springframework.aop.framework.ProxyFactory;
020import org.springframework.beans.factory.BeanClassLoaderAware;
021import org.springframework.beans.factory.FactoryBean;
022
023/**
024 * {@link FactoryBean} for RMI proxies, supporting both conventional RMI services
025 * and RMI invokers. Exposes the proxied service for use as a bean reference,
026 * using the specified service interface. Proxies will throw Spring's unchecked
027 * RemoteAccessException on remote invocation failure instead of RMI's RemoteException.
028 *
029 * <p>The service URL must be a valid RMI URL like "rmi://localhost:1099/myservice".
030 * RMI invokers work at the RmiInvocationHandler level, using the same invoker stub
031 * for any service. Service interfaces do not have to extend {@code java.rmi.Remote}
032 * or throw {@code java.rmi.RemoteException}. Of course, in and out parameters
033 * have to be serializable.
034 *
035 * <p>With conventional RMI services, this proxy factory is typically used with the
036 * RMI service interface. Alternatively, this factory can also proxy a remote RMI
037 * service with a matching non-RMI business interface, i.e. an interface that mirrors
038 * the RMI service methods but does not declare RemoteExceptions. In the latter case,
039 * RemoteExceptions thrown by the RMI stub will automatically get converted to
040 * Spring's unchecked RemoteAccessException.
041 *
042 * <p>The major advantage of RMI, compared to Hessian and Burlap, is serialization.
043 * Effectively, any serializable Java object can be transported without hassle.
044 * Hessian and Burlap have their own (de-)serialization mechanisms, but are
045 * HTTP-based and thus much easier to setup than RMI. Alternatively, consider
046 * Spring's HTTP invoker to combine Java serialization with HTTP-based transport.
047 *
048 * @author Juergen Hoeller
049 * @since 13.05.2003
050 * @see #setServiceInterface
051 * @see #setServiceUrl
052 * @see RmiClientInterceptor
053 * @see RmiServiceExporter
054 * @see java.rmi.Remote
055 * @see java.rmi.RemoteException
056 * @see org.springframework.remoting.RemoteAccessException
057 * @see org.springframework.remoting.caucho.HessianProxyFactoryBean
058 * @see org.springframework.remoting.caucho.BurlapProxyFactoryBean
059 * @see org.springframework.remoting.httpinvoker.HttpInvokerProxyFactoryBean
060 */
061public class RmiProxyFactoryBean extends RmiClientInterceptor implements FactoryBean<Object>, BeanClassLoaderAware {
062
063        private Object serviceProxy;
064
065
066        @Override
067        public void afterPropertiesSet() {
068                super.afterPropertiesSet();
069                if (getServiceInterface() == null) {
070                        throw new IllegalArgumentException("Property 'serviceInterface' is required");
071                }
072                this.serviceProxy = new ProxyFactory(getServiceInterface(), this).getProxy(getBeanClassLoader());
073        }
074
075
076        @Override
077        public Object getObject() {
078                return this.serviceProxy;
079        }
080
081        @Override
082        public Class<?> getObjectType() {
083                return getServiceInterface();
084        }
085
086        @Override
087        public boolean isSingleton() {
088                return true;
089        }
090
091}