org.springframework.ejb.support.AbstractStatelessSessionBean Maven / Gradle / Ivy
/*
* Copyright 2002-2007 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.ejb.support;
import javax.ejb.CreateException;
import javax.ejb.EJBException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* Convenient superclass for stateless session beans (SLSBs), minimizing
* the work involved in implementing an SLSB and preventing common errors.
* Note that SLSBs are the most useful kind of EJB.
*
* As the ejbActivate() and ejbPassivate() methods cannot be invoked
* on SLSBs, these methods are implemented to throw an exception and should
* not be overriden by subclasses. (Unfortunately the EJB specification
* forbids enforcing this by making EJB lifecycle methods final.)
*
*
There should be no need to override the setSessionContext()
* or ejbCreate() lifecycle methods.
*
*
Subclasses are left to implement the onEjbCreate() method
* to do whatever initialization they wish to do after their BeanFactory has
* already been loaded, and is available from the getBeanFactory()
* method.
*
*
This class provides the no-arg ejbCreate() method required
* by the EJB specification, but not the SessionBean interface, eliminating
* a common cause of EJB deployment failure.
*
* @author Rod Johnson
*/
public abstract class AbstractStatelessSessionBean extends AbstractSessionBean {
/** Logger available to subclasses */
protected final Log logger = LogFactory.getLog(getClass());
/**
* This implementation loads the BeanFactory. A BeansException thrown by
* loadBeanFactory will simply get propagated, as it is a runtime exception.
*
Don't override it (although it can't be made final): code your own
* initialization in onEjbCreate(), which is called when the BeanFactory
* is available.
*
Unfortunately we can't load the BeanFactory in setSessionContext(),
* as resource manager access isn't permitted there - but the BeanFactory
* may require it.
*/
public void ejbCreate() throws CreateException {
loadBeanFactory();
onEjbCreate();
}
/**
* Subclasses must implement this method to do any initialization
* they would otherwise have done in an ejbCreate() method.
* In contrast to ejbCreate, the BeanFactory will have been loaded here.
*
The same restrictions apply to the work of this method as
* to an ejbCreate() method.
* @throws CreateException
*/
protected abstract void onEjbCreate() throws CreateException;
/**
* @see javax.ejb.SessionBean#ejbActivate(). This method always throws an exception, as
* it should not be invoked by the EJB container.
*/
public void ejbActivate() throws EJBException {
throw new IllegalStateException("ejbActivate must not be invoked on a stateless session bean");
}
/**
* @see javax.ejb.SessionBean#ejbPassivate(). This method always throws an exception, as
* it should not be invoked by the EJB container.
*/
public void ejbPassivate() throws EJBException {
throw new IllegalStateException("ejbPassivate must not be invoked on a stateless session bean");
}
}