EventLoader.java

/**
 * Copyright (c) Lambda Innovation, 2013-2015
 * 本作品版权由Lambda Innovation所有。
 * http://www.li-dev.cn/
 *
 * This project is open-source, and it is distributed under  
 * the terms of GNU General Public License. You can modify
 * and distribute freely as long as you follow the license.
 * 本项目是一个开源项目，且遵循GNU通用公共授权协议。
 * 在遵照该协议的情况下，您可以自由传播和修改。
 * http://www.gnu.org/licenses/gpl.html
 */
package cn.liutils.cgui.loader;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import cn.liutils.cgui.gui.Widget;
import cn.liutils.cgui.gui.WidgetContainer;
import cn.liutils.cgui.gui.annotations.GuiCallback;
import cn.liutils.cgui.gui.event.GuiEvent;
import cn.liutils.cgui.gui.event.GuiEventHandler;
import cn.liutils.core.LIUtils;

/**
 * @author WeAthFolD
 */
public class EventLoader {

    public static void load(WidgetContainer widget, Object callbackProvider) {
        for(Method m : callbackProvider.getClass().getMethods()) {
            if(m.isAnnotationPresent(GuiCallback.class)) {
                //Check signature
                Class<?>[] pars = m.getParameterTypes();
                if(pars.length != 2) {
                    throw new IllegalArgumentException("Invalid par size for callback method " + m.getName());
                }
                if(pars[0] != Widget.class) {
                    throw new IllegalArgumentException("par1 not a widget for " + m.getName());
                }
                if(!GuiEvent.class.isAssignableFrom(pars[1])) {
                    throw new IllegalArgumentException("par2 not a GuiEvent for " + m.getName());
                }
                
                String path = m.getAnnotation(GuiCallback.class).value();
                Widget target = (Widget) (path.equals("") ? (widget instanceof Widget ? widget : null) : widget.getWidget(path));
                if(target == null) {
                    LIUtils.log.error("Didn't find widget named " + path + ".");
                } else {
                    target.regEventHandler(new MethodWrapper(m, callbackProvider, pars[1]));
                }
            }
        }
    }
    
    private static class MethodWrapper extends GuiEventHandler {
        
        final Method method;
        final Object instance;

        public MethodWrapper(Method m, Object i, Class ec) {
            super(ec);
            method = m;
            instance = i;
        }

        @Override
        public void handleEvent(Widget w, GuiEvent event) {
            try {
                method.invoke(instance, w, event);
            } catch (Exception e) {
                LIUtils.log.error("Exception occured trying to do event callback");
                e.printStackTrace();
                
                if(e instanceof InvocationTargetException) {
                    LIUtils.log.error("Target stack trace:");
                    ((InvocationTargetException)e).getTargetException().printStackTrace();
                }
            }
        }
        
    }
    
}