GuiEventBus.java

package cn.liutils.cgui.gui.event;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.stream.Collectors;

import cn.liutils.cgui.gui.Widget;

public final class GuiEventBus {
    
    public GuiEventBus() {}
    
    Map< Class<? extends GuiEvent>, LinkedList<GuiHandlerNode> > eventHandlers = new HashMap();
    
    public final void postEvent(Widget widget, GuiEvent event) {
        List<GuiHandlerNode> list = eventHandlers.get(event.getClass());
        if(list != null) {
            for(GuiHandlerNode n : list) {
                n.handler.handleEvent(widget, event);
            }
        }
    }
    
    public void regEventHandler(GuiEventHandler handler) {
        reg(handler.getEventClass(), handler);
    }
    
    public void regAtBeginning(GuiEventHandler handler) {
        regAtBeginning(handler.getEventClass(), handler);
    }
    
    public void reg(Class<? extends GuiEvent> clazz, IGuiEventHandler handler) {
        getRawList(clazz).add(new GuiHandlerNode(handler));
    }
    
    public void regAtBeginning(Class<? extends GuiEvent> clazz, IGuiEventHandler handler) {
        getRawList(clazz).addFirst(new GuiHandlerNode(handler));
    }
    
    public void remove(GuiEventHandler handler) {
        getRawList(handler.getEventClass()).remove(new GuiHandlerNode(handler));
    }
    
    public void remove(Class<? extends GuiEvent> clazz, IGuiEventHandler handler) {
        getRawList(clazz).remove(new GuiHandlerNode(handler));
    }
    
    private LinkedList<GuiHandlerNode> getRawList(Class<? extends GuiEvent> clazz) {
        LinkedList<GuiHandlerNode> ret = eventHandlers.get(clazz);
        if(ret == null) {
            eventHandlers.put(clazz, ret = new LinkedList());
        }
        
        return ret;
    }
    
    public GuiEventBus copy() {
        GuiEventBus ret = new GuiEventBus();
        
        for(Entry< Class<? extends GuiEvent>, LinkedList<GuiHandlerNode>> ent : eventHandlers.entrySet()) {
            ret.getRawList(ent.getKey()).addAll(ent.getValue());
        }
        return ret;
    }
    
    private class GuiHandlerNode {
        IGuiEventHandler handler;
        
        public GuiHandlerNode(IGuiEventHandler handler) {
            this.handler = handler;
        }
        
        @Override
        public boolean equals(Object another) {
            return another instanceof GuiHandlerNode && ((GuiHandlerNode) another).handler == handler;
        }
        
        @Override
        public int hashCode() {
            return handler.hashCode();
        }
    }
    
}