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/*
*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*
*/
package org.apache.qpid.server.util;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.Arrays;
/**
* Dynamic proxy that records invocations in a fixed size circular buffer,
* dumping details on hitting an exception.
* <p>
* Useful in debugging.
* <p>
*/
public class LoggingProxy implements InvocationHandler
{
private final Object _target;
private final CircularBuffer _log;
public LoggingProxy(Object target, int size)
{
_target = target;
_log = new CircularBuffer(size);
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
{
try
{
entered(method, args);
Object result = method.invoke(_target, args);
returned(method, result);
return result;
}
catch(InvocationTargetException e)
{
dump();
throw e.getTargetException();
}
}
void dump()
{
_log.dump();
}
CircularBuffer getBuffer()
{
return _log;
}
private synchronized void entered(Method method, Object[] args)
{
if (args == null)
{
_log.add(Thread.currentThread() + ": " + method.getName() + "() entered");
}
else
{
_log.add(Thread.currentThread() + ": " + method.getName() + "(" + Arrays.toString(args) + ") entered");
}
}
private synchronized void returned(Method method, Object result)
{
if (method.getReturnType() == Void.TYPE)
{
_log.add(Thread.currentThread() + ": " + method.getName() + "() returned");
}
else
{
_log.add(Thread.currentThread() + ": " + method.getName() + "() returned " + result);
}
}
public Object getProxy(Class... c)
{
return Proxy.newProxyInstance(_target.getClass().getClassLoader(), c, this);
}
public int getBufferSize() {
return _log.size();
}
}
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