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 local Stateless Session Bean (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 LocalSlsbInvokerInterceptor 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 * @author Rod Johnson
046 * @author Colin Sampaleanu
047 * @since 09.05.2003
048 * @see AbstractSlsbInvokerInterceptor#setLookupHomeOnStartup
049 * @see AbstractSlsbInvokerInterceptor#setCacheHome
050 */
051public class LocalStatelessSessionProxyFactoryBean extends LocalSlsbInvokerInterceptor
052                implements FactoryBean<Object>, BeanClassLoaderAware {
053
054        /** The business interface of the EJB we're proxying */
055        private Class<?> businessInterface;
056
057        private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();
058
059        /** EJBLocalObject */
060        private Object proxy;
061
062
063        /**
064         * Set the business interface of the EJB we're proxying.
065         * This will normally be a super-interface of the EJB local component interface.
066         * Using a business methods interface is a best practice when implementing EJBs.
067         * @param businessInterface set the business interface of the EJB
068         */
069        public void setBusinessInterface(Class<?> businessInterface) {
070                this.businessInterface = businessInterface;
071        }
072
073        /**
074         * Return the business interface of the EJB we're proxying.
075         */
076        public Class<?> getBusinessInterface() {
077                return this.businessInterface;
078        }
079
080        @Override
081        public void setBeanClassLoader(ClassLoader classLoader) {
082                this.beanClassLoader = classLoader;
083        }
084
085        @Override
086        public void afterPropertiesSet() throws NamingException {
087                super.afterPropertiesSet();
088                if (this.businessInterface == null) {
089                        throw new IllegalArgumentException("businessInterface is required");
090                }
091                this.proxy = new ProxyFactory(this.businessInterface, this).getProxy(this.beanClassLoader);
092        }
093
094
095        @Override
096        public Object getObject() {
097                return this.proxy;
098        }
099
100        @Override
101        public Class<?> getObjectType() {
102                return this.businessInterface;
103        }
104
105        @Override
106        public boolean isSingleton() {
107                return true;
108        }
109
110}