Hotswap: tentative Wicket plugin

WicketPlugin.java

import java.lang.reflect.Method;
import org.hotswap.agent.annotation.Init;
import org.hotswap.agent.annotation.OnClassLoadEvent;
import org.hotswap.agent.annotation.OnResourceFileEvent;
import org.hotswap.agent.annotation.Plugin;
import org.hotswap.agent.command.Scheduler;
import org.hotswap.agent.javassist.CannotCompileException;
import org.hotswap.agent.javassist.CtClass;
import org.hotswap.agent.javassist.NotFoundException;
import org.hotswap.agent.logging.AgentLogger;
import org.hotswap.agent.util.PluginManagerInvoker;
import org.hotswap.agent.command.Command;

@Plugin(name = "Wicket",
        description = "Apache Wicket. Clear resource bundle cache when *.properties files are changed.",
        testedVersions = { "7.10.0", "8.0.0" }
)
public class WicketPlugin {

    private static final AgentLogger LOG = AgentLogger.getLogger(WicketPlugin.class);

    @Init
    private Scheduler scheduler;

    @Init
    private ClassLoader appClassLoader;

    private final Command clearCache = new Command() {

        @Override
        public void executeCommand() {
            LOG.debug("Refreshing Wicket resource bundles.");
            try {
                Class<?> clazz = Class.forName("java.util.ResourceBundle", true, appClassLoader);
                Method clearCacheMethod = clazz.getDeclaredMethod("clearCache", ClassLoader.class);
                clearCacheMethod.invoke(null, appClassLoader);

                clearCacheMethod = Class.forName("org.apache.wicket.Localizer", true, appClassLoader).
                        getDeclaredMethod("clearCache");
                clearCacheMethod.invoke(getLocalizer());
            } catch (Exception e) {
                LOG.error("Error clear Wicket resource bundles cache", e);
            }
        }
    };

    private Object wicketApplication;

    @OnClassLoadEvent(classNameRegexp = "org.apache.wicket.protocol.http.WebApplication")
    public static void init(final CtClass ctClass) throws NotFoundException, CannotCompileException {
        String src = PluginManagerInvoker.buildInitializePlugin(WicketPlugin.class);
        src += PluginManagerInvoker.buildCallPluginMethod(WicketPlugin.class,
                "registerApplication", "this", "java.lang.Object");
        ctClass.getDeclaredConstructor(new CtClass[0]).insertAfter(src);

        LOG.info("Initialized Wicket plugin");
    }

    public void registerApplication(final Object wicketApplication) {
        this.wicketApplication = wicketApplication;

        LOG.info("Plugin {} initialized for application {}", getClass(), wicketApplication);
    }

    @OnResourceFileEvent(path = "/", filter = ".*.properties")
    public void clearLocalizerCaches() {
        scheduler.scheduleCommand(clearCache);
    }

    private Object getLocalizer() {
        try {
            Method getResourceSettingsMethod =
                    Class.forName("org.apache.wicket.Application", true, appClassLoader).
                            getDeclaredMethod("getResourceSettings");
            Method getLocalizerMethod =
                    Class.forName("org.apache.wicket.settings.ResourceSettings", true, appClassLoader).
                            getDeclaredMethod("getLocalizer");
            return getLocalizerMethod.invoke(getResourceSettingsMethod.invoke(wicketApplication));
        } catch (Exception e) {
            LOG.error("Error getting Wicket localizer", e);
            return null;
        }
    }
}