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.ejb.access;
018
019import javax.naming.NamingException;
020
021import org.springframework.aop.framework.ProxyFactory;
022import org.springframework.beans.factory.BeanClassLoaderAware;
023import org.springframework.beans.factory.FactoryBean;
024import org.springframework.util.ClassUtils;
025
026/**
027 * Convenient {@link FactoryBean} for remote SLSB proxies.
028 * Designed for EJB 2.x, but works for EJB 3 Session Beans as well.
029 *
030 * <p>See {@link org.springframework.jndi.JndiObjectLocator} for info on
031 * how to specify the JNDI location of the target EJB.
032 *
033 * <p>If you want control over interceptor chaining, use an AOP ProxyFactoryBean
034 * with SimpleRemoteSlsbInvokerInterceptor rather than rely on this class.
035 *
036 * <p>In a bean container, this class is normally best used as a singleton. However,
037 * if that bean container pre-instantiates singletons (as do the XML ApplicationContext
038 * variants) you may have a problem if the bean container is loaded before the EJB
039 * container loads the target EJB. That is because by default the JNDI lookup will be
040 * performed in the init method of this class and cached, but the EJB will not have been
041 * bound at the target location yet. The best solution is to set the lookupHomeOnStartup
042 * property to false, in which case the home will be fetched on first access to the EJB.
043 * (This flag is only true by default for backwards compatibility reasons).
044 *
045 * <p>This proxy factory is typically used with an RMI business interface, which serves
046 * as super-interface of the EJB component interface. Alternatively, this factory
047 * can also proxy a remote SLSB with a matching non-RMI business interface, i.e. an
048 * interface that mirrors the EJB business methods but does not declare RemoteExceptions.
049 * In the latter case, RemoteExceptions thrown by the EJB stub will automatically get
050 * converted to Spring's unchecked RemoteAccessException.
051 *
052 * @author Rod Johnson
053 * @author Colin Sampaleanu
054 * @author Juergen Hoeller
055 * @since 09.05.2003
056 * @see org.springframework.remoting.RemoteAccessException
057 * @see AbstractSlsbInvokerInterceptor#setLookupHomeOnStartup
058 * @see AbstractSlsbInvokerInterceptor#setCacheHome
059 * @see AbstractRemoteSlsbInvokerInterceptor#setRefreshHomeOnConnectFailure
060 */
061public class SimpleRemoteStatelessSessionProxyFactoryBean extends SimpleRemoteSlsbInvokerInterceptor
062        implements FactoryBean<Object>, BeanClassLoaderAware {
063
064        /** The business interface of the EJB we're proxying */
065        private Class<?> businessInterface;
066
067        private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
068
069        /** EJBObject */
070        private Object proxy;
071
072
073        /**
074         * Set the business interface of the EJB we're proxying.
075         * This will normally be a super-interface of the EJB remote component interface.
076         * Using a business methods interface is a best practice when implementing EJBs.
077         * <p>You can also specify a matching non-RMI business interface, i.e. an interface
078         * that mirrors the EJB business methods but does not declare RemoteExceptions.
079         * In this case, RemoteExceptions thrown by the EJB stub will automatically get
080         * converted to Spring's generic RemoteAccessException.
081         * @param businessInterface the business interface of the EJB
082         */
083        public void setBusinessInterface(Class<?> businessInterface) {
084                this.businessInterface = businessInterface;
085        }
086
087        /**
088         * Return the business interface of the EJB we're proxying.
089         */
090        public Class<?> getBusinessInterface() {
091                return this.businessInterface;
092        }
093
094        @Override
095        public void setBeanClassLoader(ClassLoader classLoader) {
096                this.beanClassLoader = classLoader;
097        }
098
099        @Override
100        public void afterPropertiesSet() throws NamingException {
101                super.afterPropertiesSet();
102                if (this.businessInterface == null) {
103                        throw new IllegalArgumentException("businessInterface is required");
104                }
105                this.proxy = new ProxyFactory(this.businessInterface, this).getProxy(this.beanClassLoader);
106        }
107
108
109        @Override
110        public Object getObject() {
111                return this.proxy;
112        }
113
114        @Override
115        public Class<?> getObjectType() {
116                return this.businessInterface;
117        }
118
119        @Override
120        public boolean isSingleton() {
121                return true;
122        }
123
124}