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1
4 package com.tc.common.proxy;
5
6 import java.lang.reflect.InvocationHandler  ;
7 import java.lang.reflect.InvocationTargetException ;
8 import java.lang.reflect.Method ;
9 import java.lang.reflect.Proxy ;
10
11
14 public class MethodMonitorProxy {
15 public static Object createProxy(final Object objectToMonitor, MethodInvocationEventListener listener) {
16 return createProxy(objectToMonitor, new MethodInvocationEventListener[] { listener });
17 }
18
19 public static Object createProxy(final Object objectToMonitor, MethodInvocationEventListener listeners[]) {
20 if (null == objectToMonitor) { throw new NullPointerException ("Cannot proxy a null instance"); }
21 if (null == listeners) { throw new NullPointerException ("Listener list cannot be null"); }
22
23 for (int i = 0; i < listeners.length; i++) {
24 if (null == listeners[i]) { throw new NullPointerException ("Null listener in list at position " + i); }
25 }
26
27 final Class clazz = objectToMonitor.getClass();
28 final Class [] interfaces = clazz.getInterfaces();
29
30 if (0 == interfaces.length) { throw new IllegalArgumentException ("Class (" + clazz.getName()
31 + ") does not implement any interfaces"); }
32
33 return Proxy.newProxyInstance(clazz.getClassLoader(), interfaces, new MonitorHandler(objectToMonitor, listeners));
34 }
35
36 private static class MonitorHandler implements InvocationHandler {
37 private final MethodInvocationEventListener[] listeners;
38 private final Object delegate;
39
40 MonitorHandler(Object delegate, MethodInvocationEventListener[] listeners) {
41 this.listeners = (MethodInvocationEventListener[]) listeners.clone();
42 this.delegate = delegate;
43 }
44
45 public Object invoke(Object proxy, Method method, Object [] args) throws Throwable {
46 Throwable exception = null;
47
48 Object returnValue = null;
49
50 final long end;
51 final long start = System.currentTimeMillis();
52 try {
53 returnValue = method.invoke(delegate, args);
54 } catch (InvocationTargetException ite) {
55 exception = ite.getCause();
56 } finally {
57 end = System.currentTimeMillis();
58 }
59
60 final MethodInvocationEvent event = new MethodInvocationEventImpl(start, end, delegate, method, args, exception,
61 returnValue);
62 for (int i = 0; i < listeners.length; i++) {
63 listeners[i].methodInvoked(event);
64 }
65
66 if (null != exception) {
67 throw exception;
68 } else {
69 return returnValue;
70 }
71 }
72 }
73 } |
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