01: /*
02: * Copyright 2002-2007 the original author or authors.
03: *
04: * Licensed under the Apache License, Version 2.0 (the "License");
05: * you may not use this file except in compliance with the License.
06: * You may obtain a copy of the License at
07: *
08: * http://www.apache.org/licenses/LICENSE-2.0
09: *
10: * Unless required by applicable law or agreed to in writing, software
11: * distributed under the License is distributed on an "AS IS" BASIS,
12: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13: * See the License for the specific language governing permissions and
14: * limitations under the License.
15: */
16:
17: package org.springframework.ejb.support;
18:
19: import javax.ejb.MessageDrivenBean;
20: import javax.ejb.MessageDrivenContext;
21:
22: import org.apache.commons.logging.Log;
23: import org.apache.commons.logging.LogFactory;
24:
25: /**
26: * Convenient superclass for MDBs.
27: * Doesn't require JMS, as EJB 2.1 MDBs are no longer JMS-specific;
28: * see the {@link AbstractJmsMessageDrivenBean} subclass.
29: *
30: * <p>This class ensures that subclasses have access to the
31: * MessageDrivenContext provided by the EJB container, and implement
32: * a no-arg <code>ejbCreate()</code> method as required by the EJB
33: * specification. This <code>ejbCreate()</code> method loads a BeanFactory,
34: * before invoking the <code>onEjbCreate()</code> method, which is
35: * supposed to contain subclass-specific initialization.
36: *
37: * <p>NB: We cannot use final methods to implement EJB API methods,
38: * as this violates the EJB specification. However, there should be
39: * no need to override the <code>setMessageDrivenContext</code> or
40: * <code>ejbCreate()</code> methods.
41: *
42: * @author Rod Johnson
43: */
44: public abstract class AbstractMessageDrivenBean extends
45: AbstractEnterpriseBean implements MessageDrivenBean {
46:
47: /** Logger available to subclasses */
48: protected final Log logger = LogFactory.getLog(getClass());
49:
50: private MessageDrivenContext messageDrivenContext;
51:
52: /**
53: * Required lifecycle method. Sets the MessageDriven context.
54: * @param messageDrivenContext MessageDrivenContext
55: */
56: public void setMessageDrivenContext(
57: MessageDrivenContext messageDrivenContext) {
58: this .messageDrivenContext = messageDrivenContext;
59: }
60:
61: /**
62: * Convenience method for subclasses to use.
63: * @return the MessageDrivenContext passed to this EJB by the EJB container
64: */
65: protected final MessageDrivenContext getMessageDrivenContext() {
66: return this .messageDrivenContext;
67: }
68:
69: /**
70: * Lifecycle method required by the EJB specification but not the
71: * MessageDrivenBean interface. This implementation loads the BeanFactory.
72: * <p>Don't override it (although it can't be made final): code initialization
73: * in onEjbCreate(), which is called when the BeanFactory is available.
74: * <p>Unfortunately we can't load the BeanFactory in setSessionContext(),
75: * as resource manager access isn't permitted and the BeanFactory may require it.
76: */
77: public void ejbCreate() {
78: loadBeanFactory();
79: onEjbCreate();
80: }
81:
82: /**
83: * Subclasses must implement this method to do any initialization they would
84: * otherwise have done in an <code>ejbCreate()</code> method. In contrast
85: * to <code>ejbCreate()</code>, the BeanFactory will have been loaded here.
86: * <p>The same restrictions apply to the work of this method as
87: * to an <code>ejbCreate()</code> method.
88: */
89: protected abstract void onEjbCreate();
90:
91: }
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