UptimeClientHandler.java — netty Source File

Source Code

/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you 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:
 *
 *   https://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 io.netty.example.uptime;

import io.netty.channel.ChannelHandler.Sharable;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;

import java.util.concurrent.TimeUnit;

/**
 * Keep reconnecting to the server while printing out the current uptime and
 * connection attempt getStatus.
 */
@Sharable
public class UptimeClientHandler extends SimpleChannelInboundHandler<Object> {

    long startTime = -1;

    @Override
    public void channelActive(ChannelHandlerContext ctx) {
        if (startTime < 0) {
            startTime = System.currentTimeMillis();
        }
        println("Connected to: " + ctx.channel().remoteAddress());
    }

    @Override
    public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception {
        // Discard received data
    }

    @Override
    public void userEventTriggered(ChannelHandlerContext ctx, Object evt) {
        if (!(evt instanceof IdleStateEvent)) {
            return;
        }

        IdleStateEvent e = (IdleStateEvent) evt;
        if (e.state() == IdleState.READER_IDLE) {
            // The connection was OK but there was no traffic for last period.
            println("Disconnecting due to no inbound traffic");
            ctx.close();
        }
    }

    @Override
    public void channelInactive(final ChannelHandlerContext ctx) {
        println("Disconnected from: " + ctx.channel().remoteAddress());
    }

    @Override
    public void channelUnregistered(final ChannelHandlerContext ctx) throws Exception {
        println("Sleeping for: " + UptimeClient.RECONNECT_DELAY + 's');

        ctx.channel().eventLoop().schedule(new Runnable() {
            @Override
            public void run() {
                println("Reconnecting to: " + UptimeClient.HOST + ':' + UptimeClient.PORT);
                UptimeClient.connect();
            }
        }, UptimeClient.RECONNECT_DELAY, TimeUnit.SECONDS);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
        cause.printStackTrace();
        ctx.close();
    }

    void println(String msg) {
        if (startTime < 0) {
            System.err.format("[SERVER IS DOWN] %s%n", msg);
        } else {
            System.err.format("[UPTIME: %5ds] %s%n", (System.currentTimeMillis() - startTime) / 1000, msg);
        }
    }
}