/*
 * Copyright 2016-2018 shardingsphere.io.
 * <p>
 * Licensed 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.
 * </p>
 */

package io.shardingsphere.proxy.frontend.common;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.shardingsphere.proxy.frontend.common.executor.ChannelThreadExecutorGroup;

/**
 * Frontend handler.
 * 
 * @author zhangliang 
 */
public abstract class FrontendHandler extends ChannelInboundHandlerAdapter {
    
    private boolean authorized;
    
    @Override
    public void channelActive(final ChannelHandlerContext context) {
        ChannelThreadExecutorGroup.getInstance().register(context.channel().id());
        handshake(context);
    }
    
    protected abstract void handshake(ChannelHandlerContext context);
    
    @Override
    public void channelRead(final ChannelHandlerContext context, final Object message) {
        if (!authorized) {
            auth(context, (ByteBuf) message);
            authorized = true;
        } else {
            executeCommand(context, (ByteBuf) message);
        }
    }
    
    protected abstract void auth(ChannelHandlerContext context, ByteBuf message);
    
    protected abstract void executeCommand(ChannelHandlerContext context, ByteBuf message);
    
    @Override
    public void channelInactive(final ChannelHandlerContext context) {
        context.fireChannelInactive();
        ChannelThreadExecutorGroup.getInstance().unregister(context.channel().id());
    }
}

@@ -2036,10 +2036,285 @@
 ;%0A    %7D%0A
+    %0A    @Override%0A    public void channelWritabilityChanged(final ChannelHandlerContext context) %7B%0A        context.fireChannelWritabilityChanged();%0A        if (context.channel().isWritable()) %7B%0A            // TODO MySQLFrontendHandler line 124, trigger here%0A        %7D%0A    %7D%0A
 %7D%0A

add channelWritabilityChanged hook, but not implement yet