https://github.com/spring-projects/spring-framework: Spring Context (Spring IO)
  • Juergen Hoeller 
/*
 * Copyright 2002-2017 the original author or authors.
 *
 * 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.springframework.remoting.rmi;

import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.util.Assert;


FactoryBean for RMI proxies, supporting both conventional RMI services and RMI invokers. Exposes the proxied service for use as a bean reference, using the specified service interface. Proxies will throw Spring's unchecked RemoteAccessException on remote invocation failure instead of RMI's RemoteException. 
The service URL must be a valid RMI URL like "rmi://localhost:1099/myservice". RMI invokers work at the RmiInvocationHandler level, using the same invoker stub for any service. Service interfaces do not have to extend java.rmi.Remote or throw java.rmi.RemoteException. Of course, in and out parameters have to be serializable. 
With conventional RMI services, this proxy factory is typically used with the
RMI service interface. Alternatively, this factory can also proxy a remote RMI
service with a matching non-RMI business interface, i.e. an interface that mirrors
the RMI service methods but does not declare RemoteExceptions. In the latter case,
RemoteExceptions thrown by the RMI stub will automatically get converted to
Spring's unchecked RemoteAccessException.

The major advantage of RMI, compared to Hessian, is serialization.
Effectively, any serializable Java object can be transported without hassle.
Hessian has its own (de-)serialization mechanisms, but is HTTP-based and thus
much easier to setup than RMI. Alternatively, consider Spring's HTTP invoker
to combine Java serialization with HTTP-based transport.

Author:Juergen Hoeller
See Also:
Since:13.05.2003
/**
 * {@link FactoryBean} for RMI proxies, supporting both conventional RMI services
 * and RMI invokers. Exposes the proxied service for use as a bean reference,
 * using the specified service interface. Proxies will throw Spring's unchecked
 * RemoteAccessException on remote invocation failure instead of RMI's RemoteException.
 *
 * <p>The service URL must be a valid RMI URL like "rmi://localhost:1099/myservice".
 * RMI invokers work at the RmiInvocationHandler level, using the same invoker stub
 * for any service. Service interfaces do not have to extend {@code java.rmi.Remote}
 * or throw {@code java.rmi.RemoteException}. Of course, in and out parameters
 * have to be serializable.
 *
 * <p>With conventional RMI services, this proxy factory is typically used with the
 * RMI service interface. Alternatively, this factory can also proxy a remote RMI
 * service with a matching non-RMI business interface, i.e. an interface that mirrors
 * the RMI service methods but does not declare RemoteExceptions. In the latter case,
 * RemoteExceptions thrown by the RMI stub will automatically get converted to
 * Spring's unchecked RemoteAccessException.
 *
 * <p>The major advantage of RMI, compared to Hessian, is serialization.
 * Effectively, any serializable Java object can be transported without hassle.
 * Hessian has its own (de-)serialization mechanisms, but is HTTP-based and thus
 * much easier to setup than RMI. Alternatively, consider Spring's HTTP invoker
 * to combine Java serialization with HTTP-based transport.
 *
 * @author Juergen Hoeller
 * @since 13.05.2003
 * @see #setServiceInterface
 * @see #setServiceUrl
 * @see RmiClientInterceptor
 * @see RmiServiceExporter
 * @see java.rmi.Remote
 * @see java.rmi.RemoteException
 * @see org.springframework.remoting.RemoteAccessException
 * @see org.springframework.remoting.caucho.HessianProxyFactoryBean
 * @see org.springframework.remoting.httpinvoker.HttpInvokerProxyFactoryBean
 */
public class RmiProxyFactoryBean extends RmiClientInterceptor implements FactoryBean<Object>, BeanClassLoaderAware {

	private Object serviceProxy;


	@Override
	public void afterPropertiesSet() {
		super.afterPropertiesSet();
		Class<?> ifc = getServiceInterface();
		Assert.notNull(ifc, "Property 'serviceInterface' is required");
		this.serviceProxy = new ProxyFactory(ifc, this).getProxy(getBeanClassLoader());
	}


	@Override
	public Object getObject() {
		return this.serviceProxy;
	}

	@Override
	public Class<?> getObjectType() {
		return getServiceInterface();
	}

	@Override
	public boolean isSingleton() {
		return true;
	}

}