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Java > Open Source Codes > org > springframework > web > context > support > PerformanceMonitorListener


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.web.context.support;
18
19 import org.apache.commons.logging.Log;
20 import org.apache.commons.logging.LogFactory;
21
22 import org.springframework.context.ApplicationEvent;
23 import org.springframework.context.ApplicationListener;
24 import org.springframework.util.ResponseTimeMonitorImpl;
25
26 /**
27  * Listener that logs the response times of web requests.
28  * To be registered as bean in a WebApplicationContext.
29  *
30  * <p>Logs performance statistics using Commons Logging at "trace" level.
31  *
32  * @author Rod Johnson
33  * @author Juergen Hoeller
34  * @since January 21, 2001
35  * @see RequestHandledEvent
36  */
37 public class PerformanceMonitorListener implements ApplicationListener {
38
39     protected final Log logger = LogFactory.getLog(getClass());
40
41     protected final ResponseTimeMonitorImpl responseTimeMonitor = new ResponseTimeMonitorImpl();
42
43
44     public void onApplicationEvent(ApplicationEvent event) {
45         if (event instanceof RequestHandledEvent) {
46             RequestHandledEvent rhe = (RequestHandledEvent) event;
47             this.responseTimeMonitor.recordResponseTime(rhe.getProcessingTimeMillis());
48             if (logger.isTraceEnabled()) {
49                 // Stringifying objects is expensive. Don't do it unless it will show.
50 logger.trace("PerformanceMonitorListener: last=[" + rhe.getProcessingTimeMillis() + "ms]; " +
51                         this.responseTimeMonitor + "; " + rhe.getShortDescription());
52             }
53         }
54     }
55
56 }
57
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