/*
 * Copyright 2014 The Skfiy Open Association.
 *
 * 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.
 */
package org.skfiy.typhon.net;

import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import java.util.concurrent.atomic.AtomicInteger;
import org.skfiy.typhon.Typhons;

/**
 *
 * @author Kevin Zou <kevinz@skfiy.org>
 */
@Sharable
public class Netty4ConnectionLimitHandler extends ChannelInboundHandlerAdapter {

    private final AtomicInteger connections = new AtomicInteger(0);

    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        int maxConnections = Typhons.getInteger("typhon.netty4.maxConnections", 500);

        int conns = connections.getAndIncrement();
        if (conns + 1 > maxConnections) {
            ctx.channel().close();
            connections.decrementAndGet();
            return;
        }

        super.channelActive(ctx);
    }

    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        connections.decrementAndGet();

        super.channelInactive(ctx);
    }

}