001/*
002 * (C) Copyright 2010 Nuxeo SAS (http://nuxeo.com/) and contributors.
003 *
004 * All rights reserved. This program and the accompanying materials
005 * are made available under the terms of the GNU Lesser General Public License
006 * (LGPL) version 2.1 which accompanies this distribution, and is available at
007 * http://www.gnu.org/licenses/lgpl.html
008 *
009 * This library is distributed in the hope that it will be useful,
010 * but WITHOUT ANY WARRANTY; without even the implied warranty of
011 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012 * Lesser General Public License for more details.
013 *
014 * Contributors:
015 *     Nuxeo - initial API and implementation
016 */
017
018package org.nuxeo.runtime.management.metrics;
019
020import java.lang.reflect.InvocationHandler;
021import java.lang.reflect.InvocationTargetException;
022import java.lang.reflect.Method;
023import java.lang.reflect.Proxy;
024
025import org.javasimon.SimonManager;
026import org.javasimon.Split;
027import org.javasimon.Stopwatch;
028
029public class MetricInvocationHandler<T> implements InvocationHandler {
030
031    protected final T proxied;
032
033    protected MetricInvocationHandler(T proxied) {
034        this.proxied = proxied;
035    }
036
037    @SuppressWarnings("unchecked")
038    public static <T> T newProxy(T proxied, Class<?>... classes) {
039        MetricInvocationHandler<T> handler = new MetricInvocationHandler<T>(proxied);
040        return (T) Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(), classes, handler);
041    }
042
043    protected String formatParms(Object... parms) {
044        if (parms == null) {
045            return "";
046        }
047        StringBuffer buffer = new StringBuffer();
048        for (Object parm : parms) {
049            buffer.append(".").append(parm);
050        }
051        return buffer.toString();
052    }
053
054    protected String formatName(Method m, Object[] parms) {
055        Class<?> declaringClass = m.getDeclaringClass();
056        return String.format("%s.%s", declaringClass.getSimpleName(), m.getName());
057    }
058
059    protected String formatNote(Method m, Object[] parms) {
060        return String.format("%s#%s(%s)", m.getDeclaringClass().getSimpleName(), m.getName(), formatParms(parms));
061    }
062
063    protected Stopwatch getStopwatch(Method m, Object[] parms) {
064        String name = formatName(m, parms);
065        Stopwatch stopwatch = SimonManager.getStopwatch(name);
066        stopwatch.setNote(formatNote(m, parms));
067        return stopwatch;
068    }
069
070    @Override
071    public Object invoke(Object proxy, Method m, Object[] parms) throws Throwable {
072        Split split = getStopwatch(m, parms).start();
073        try {
074            return m.invoke(proxied, parms);
075        } catch (InvocationTargetException e) {
076            throw e.getTargetException();
077        } finally {
078            split.stop();
079        }
080    }
081
082}