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Java > Open Source Codes > org > springframework > context > event > EventPublicationInterceptor


1 /*
2  * Copyright 2002-2006 the original author or authors.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  * http://www.apache.org/licenses/LICENSE-2.0
9  *
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.context.event;
18
19 import java.lang.reflect.Constructor JavaDoc;
20
21 import org.aopalliance.intercept.MethodInterceptor;
22 import org.aopalliance.intercept.MethodInvocation;
23
24 import org.springframework.beans.factory.InitializingBean;
25 import org.springframework.context.ApplicationEvent;
26 import org.springframework.context.ApplicationEventPublisher;
27 import org.springframework.context.ApplicationEventPublisherAware;
28
29 /**
30  * {@link MethodInterceptor Interceptor} that publishes an
31  * <code>ApplicationEvent</code> to all <code>ApplicationListeners</code>
32  * registered with an <code>ApplicationEventPublisher</code> after each
33  * <i>successful</i> method invocation.
34  *
35  * <p>Note that this interceptor is only capable of publishing <i>stateless</i>
36  * events configured via the
37  * {@link #setApplicationEventClass "applicationEventClass"} property.
38  *
39  * @author Dmitriy Kopylenko
40  * @author Juergen Hoeller
41  * @author Rick Evans
42  * @see #setApplicationEventClass
43  * @see org.springframework.context.ApplicationEvent
44  * @see org.springframework.context.ApplicationListener
45  * @see org.springframework.context.ApplicationEventPublisher
46  * @see org.springframework.context.ApplicationContext
47  */
48 public class EventPublicationInterceptor
49         implements MethodInterceptor, ApplicationEventPublisherAware, InitializingBean {
50
51     private Constructor JavaDoc applicationEventClassConstructor;
52
53     private ApplicationEventPublisher applicationEventPublisher;
54
55
56     /**
57      * Set the application event class to publish.
58      * <p>The event class <b>must</b> have a constructor with a single
59      * <code>Object</code> argument for the event source. The interceptor
60      * will pass in the invoked object.
61      * @throws IllegalArgumentException if the supplied <code>Class</code> is
62      * <code>null</code> or if it is not an <code>ApplicationEvent</code> subclass or
63      * if it does not expose a constructor that takes a single <code>Object</code> argument
64      */
65     public void setApplicationEventClass(Class JavaDoc applicationEventClass) {
66         if (ApplicationEvent.class.equals(applicationEventClass) ||
67             !ApplicationEvent.class.isAssignableFrom(applicationEventClass)) {
68             throw new IllegalArgumentException JavaDoc("applicationEventClass needs to extend ApplicationEvent");
69         }
70         try {
71             this.applicationEventClassConstructor =
72                     applicationEventClass.getConstructor(new Class JavaDoc[] {Object JavaDoc.class});
73         }
74         catch (NoSuchMethodException JavaDoc ex) {
75             throw new IllegalArgumentException JavaDoc("applicationEventClass [" +
76                     applicationEventClass.getName() + "] does not have the required Object constructor: " + ex);
77         }
78     }
79
80     public void setApplicationEventPublisher(ApplicationEventPublisher applicationEventPublisher) {
81         this.applicationEventPublisher = applicationEventPublisher;
82     }
83
84     public void afterPropertiesSet() throws Exception JavaDoc {
85         if (this.applicationEventClassConstructor == null) {
86             throw new IllegalArgumentException JavaDoc("applicationEventClass is required");
87         }
88     }
89
90
91     public Object JavaDoc invoke(MethodInvocation invocation) throws Throwable JavaDoc {
92         Object JavaDoc retVal = invocation.proceed();
93
94         ApplicationEvent event = (ApplicationEvent)
95                 this.applicationEventClassConstructor.newInstance(new Object JavaDoc[] {invocation.getThis()});
96         this.applicationEventPublisher.publishEvent(event);
97
98         return retVal;
99     }
100
101 }
102
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