/*
 * Copyright 2002-2018 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
 *
 *      https://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.ejb.access;

import javax.naming.NamingException;

import org.springframework.aop.framework.ProxyFactory;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.lang.Nullable;
import org.springframework.util.ClassUtils;

Convenient FactoryBean for local Stateless Session Bean (SLSB) proxies. Designed for EJB 2.x, but works for EJB 3 Session Beans as well. 
See JndiObjectLocator for info on how to specify the JNDI location of the target EJB. 
If you want control over interceptor chaining, use an AOP ProxyFactoryBean
with LocalSlsbInvokerInterceptor rather than rely on this class.
In a bean container, this class is normally best used as a singleton. However,
if that bean container pre-instantiates singletons (as do the XML ApplicationContext
variants) you may have a problem if the bean container is loaded before the EJB
container loads the target EJB. That is because by default the JNDI lookup will be
performed in the init method of this class and cached, but the EJB will not have been
bound at the target location yet. The best solution is to set the "lookupHomeOnStartup"
property to "false", in which case the home will be fetched on first access to the EJB.
(This flag is only true by default for backwards compatibility reasons).
Author:
Rod Johnson, Colin Sampaleanu
See Also:
AbstractSlsbInvokerInterceptor.setLookupHomeOnStartup
AbstractSlsbInvokerInterceptor.setCacheHome
Since:
09.05.2003/**
 * Convenient {@link FactoryBean} for local Stateless Session Bean (SLSB) proxies.
 * Designed for EJB 2.x, but works for EJB 3 Session Beans as well.
 *
 * <p>See {@link org.springframework.jndi.JndiObjectLocator} for info on
 * how to specify the JNDI location of the target EJB.
 *
 * <p>If you want control over interceptor chaining, use an AOP ProxyFactoryBean
 * with LocalSlsbInvokerInterceptor rather than rely on this class.
 *
 * <p>In a bean container, this class is normally best used as a singleton. However,
 * if that bean container pre-instantiates singletons (as do the XML ApplicationContext
 * variants) you may have a problem if the bean container is loaded before the EJB
 * container loads the target EJB. That is because by default the JNDI lookup will be
 * performed in the init method of this class and cached, but the EJB will not have been
 * bound at the target location yet. The best solution is to set the "lookupHomeOnStartup"
 * property to "false", in which case the home will be fetched on first access to the EJB.
 * (This flag is only true by default for backwards compatibility reasons).
 *
 * @author Rod Johnson
 * @author Colin Sampaleanu
 * @since 09.05.2003
 * @see AbstractSlsbInvokerInterceptor#setLookupHomeOnStartup
 * @see AbstractSlsbInvokerInterceptor#setCacheHome
 */
public class LocalStatelessSessionProxyFactoryBean extends LocalSlsbInvokerInterceptor
		implements FactoryBean<Object>, BeanClassLoaderAware {

	
The business interface of the EJB we're proxying. /** The business interface of the EJB we're proxying. */
	@Nullable
	private Class<?> businessInterface;

	@Nullable
	private ClassLoader beanClassLoader = ClassUtils.getDefaultClassLoader();

	
EJBLocalObject. /** EJBLocalObject. */
	@Nullable
	private Object proxy;


	
Set the business interface of the EJB we're proxying.
This will normally be a super-interface of the EJB local component interface.
Using a business methods interface is a best practice when implementing EJBs.
Params:
businessInterface – set the business interface of the EJB/**
	 * Set the business interface of the EJB we're proxying.
	 * This will normally be a super-interface of the EJB local component interface.
	 * Using a business methods interface is a best practice when implementing EJBs.
	 * @param businessInterface set the business interface of the EJB
	 */
	public void setBusinessInterface(@Nullable Class<?> businessInterface) {
		this.businessInterface = businessInterface;
	}

	
Return the business interface of the EJB we're proxying.
/**
	 * Return the business interface of the EJB we're proxying.
	 */
	@Nullable
	public Class<?> getBusinessInterface() {
		return this.businessInterface;
	}

	@Override
	public void setBeanClassLoader(ClassLoader classLoader) {
		this.beanClassLoader = classLoader;
	}

	@Override
	public void afterPropertiesSet() throws NamingException {
		super.afterPropertiesSet();
		if (this.businessInterface == null) {
			throw new IllegalArgumentException("businessInterface is required");
		}
		this.proxy = new ProxyFactory(this.businessInterface, this).getProxy(this.beanClassLoader);
	}


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

	@Override
	public Class<?> getObjectType() {
		return this.businessInterface;
	}

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

}