1 /***
2 *
3 * Copyright 2004 Protique Ltd
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 **/
18
19 package org.codehaus.activemq.util;
20
21 import EDU.oswego.cs.dl.util.concurrent.Executor;
22 import org.apache.commons.logging.Log;
23 import org.apache.commons.logging.LogFactory;
24
25 import java.lang.reflect.InvocationHandler;
26 import java.lang.reflect.Method;
27 import java.lang.reflect.Proxy;
28
29 /***
30 * A proxy to some service which offers an asynchronous way to invoke methods which
31 * are void and don't throw exceptions. Calling the method results in a command object
32 * being added to a queue for later execution.
33 *
34 * @version $Revision: 1.1 $
35 */
36 public class AsyncProxy implements InvocationHandler {
37
38 private Object realObject;
39 private Executor executor;
40 private Log log;
41
42 public static Object createProxy(Class interfaceType, Object realObject, Executor executor) {
43 return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
44 new Class[]{interfaceType},
45 new AsyncProxy(realObject, executor));
46 }
47
48 public AsyncProxy(Object realObject, Executor executor) {
49 this(realObject, executor, LogFactory.getLog(AsyncProxy.class));
50 }
51
52 public AsyncProxy(Object realObject, Executor executor, Log log) {
53 this.realObject = realObject;
54 this.executor = executor;
55 this.log = log;
56 }
57
58 public AsyncProxy(Executor executor, Log log) {
59 this.executor = executor;
60 this.log = log;
61 }
62
63 public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
64 if (method.getReturnType() == void.class) {
65 executor.execute(new Runnable() {
66 public void run() {
67 doAsyncMethodInvoke(method, args);
68 }
69 });
70 return null;
71 }
72 else {
73 return method.invoke(realObject, args);
74 }
75 }
76
77 protected void doAsyncMethodInvoke(Method method, Object[] args) {
78 try {
79 method.invoke(realObject, args);
80 }
81 catch (Throwable e) {
82 log.warn("Caught exception: " + e, e);
83 }
84 }
85 }