CallProxy.java

/**
 * Copyright (c) 2002-2011 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.neo4j.jdbc;

import javax.swing.*;
import java.io.PrintWriter;
import java.io.StringWriter;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.logging.Logger;

/**
 * This implements driver debugging functionality. Method calls and results are logged to JUL.
 */
public class CallProxy
    implements InvocationHandler
{
    public static <T> T proxy(Class<T> clazz, T next)
    {
        return clazz.cast(Proxy.newProxyInstance(clazz.getClassLoader(), new Class[]{clazz}, new CallProxy(next)));
    }

    private static void log(final String str)
    {
        Logger.getLogger(Driver.class.getName()).info(str);
    }

    private Object next;

    public CallProxy(Object next)
    {
        this.next = next;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable
    {
        if (!method.getDeclaringClass().equals(Object.class))
        {
            String call = method.getDeclaringClass().getSimpleName()+"."+method.getName()+"(";
            if (args != null)
            {
                String comma = "";
                for (Object arg : args)
                {
                    call+= comma + (arg == null ? "null": arg.toString());
                    comma = ", ";
                }
            }
            call+=")";

            log(call);
            try
            {
                final Object result = method.invoke(next, args);
                if (!method.getReturnType().equals(Void.TYPE))
                    log("->"+result+"\n");
                return result;
            } catch (InvocationTargetException e)
            {
                StringWriter str = new StringWriter();
                PrintWriter print = new PrintWriter(str, true);
                e.printStackTrace(print);
                throw e.getTargetException();
            }
        } else
            return method.invoke(next, args);
    }
}