/*
* 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.wicket.util.instrument;
import java.lang.instrument.Instrumentation;
import org.apache.wicket.core.util.lang.WicketObjects;
import org.apache.wicket.core.util.lang.WicketObjects.IObjectSizeOfStrategy;
/**
* Instrumentation agent for calculating object sizes using Java's instrumentation API. To use it,
* have the jar somewhere we you can access it (just having this class on the classpath is not
* enough) and startup your application with a -javaagent argument like e.g:
* '-javaagent:/mydir/wicket-objectsizeof-agent-1.3-SNAPSHOT.jar'. When the application starts up,
* this agent will register an {@link IObjectSizeOfStrategy} at
* {@link WicketObjects#setObjectSizeOfStrategy(IObjectSizeOfStrategy)}. Note that this is a static
* registration.
*
* @author eelcohillenius
*/
public class ObjectSizeOfAgent
{
/**
* Initializes agent when it is attached to an already running JVM.
*
* @param agentArgs
* Arguments passed in to the agent
* @param instrumentation
* The instrumentation class
*/
public static void agentmain(String agentArgs, Instrumentation instrumentation)
{
InstrumentationObjectSizeOfStrategy strategy = new InstrumentationObjectSizeOfStrategy(
instrumentation);
WicketObjects.setObjectSizeOfStrategy(strategy);
}
/**
* Initializes agent before the main function of the application is executed.
*
* @param agentArgs
* Arguments passed in to the agent
* @param instrumentation
* The instrumentation class
*/
public static void premain(String agentArgs, Instrumentation instrumentation)
{
InstrumentationObjectSizeOfStrategy strategy = new InstrumentationObjectSizeOfStrategy(
instrumentation);
WicketObjects.setObjectSizeOfStrategy(strategy);
}
}