001/*
002 * (C) Copyright 2010 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 * Contributors:
017 *     Nuxeo - initial API and implementation
018 */
019
020package org.nuxeo.runtime.management.metrics;
021
022import java.lang.reflect.InvocationHandler;
023import java.lang.reflect.InvocationTargetException;
024import java.lang.reflect.Method;
025import java.lang.reflect.Proxy;
026
027import org.javasimon.SimonManager;
028import org.javasimon.Split;
029import org.javasimon.Stopwatch;
030
031public class MetricInvocationHandler<T> implements InvocationHandler {
032
033    protected final T proxied;
034
035    protected MetricInvocationHandler(T proxied) {
036        this.proxied = proxied;
037    }
038
039    @SuppressWarnings("unchecked")
040    public static <T> T newProxy(T proxied, Class<?>... classes) {
041        MetricInvocationHandler<T> handler = new MetricInvocationHandler<T>(proxied);
042        return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(), classes, handler);
043    }
044
045    protected String formatParms(Object... parms) {
046        if (parms == null) {
047            return "";
048        }
049        StringBuffer buffer = new StringBuffer();
050        for (Object parm : parms) {
051            buffer.append(".").append(parm);
052        }
053        return buffer.toString();
054    }
055
056    protected String formatName(Method m, Object[] parms) {
057        Class<?> declaringClass = m.getDeclaringClass();
058        return String.format("%s.%s", declaringClass.getSimpleName(), m.getName());
059    }
060
061    protected String formatNote(Method m, Object[] parms) {
062        return String.format("%s#%s(%s)", m.getDeclaringClass().getSimpleName(), m.getName(), formatParms(parms));
063    }
064
065    protected Stopwatch getStopwatch(Method m, Object[] parms) {
066        String name = formatName(m, parms);
067        Stopwatch stopwatch = SimonManager.getStopwatch(name);
068        stopwatch.setNote(formatNote(m, parms));
069        return stopwatch;
070    }
071
072    @Override
073    public Object invoke(Object proxy, Method m, Object[] parms) throws Throwable {
074        Split split = getStopwatch(m, parms).start();
075        try {
076            return m.invoke(proxied, parms);
077        } catch (InvocationTargetException e) {
078            throw e.getTargetException();
079        } finally {
080            split.stop();
081        }
082    }
083
084}