FactorialClient.java

/*
 * 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:
 *
 *   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 evanq.game.net.netty;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;

/**
 * Sends a sequence of integers to a {@link FactorialServer} to calculate
 * the factorial of the specified integer.
 */
public class FactorialClient {

    private final String host;
    private final int port;
    private final int count;

    public FactorialClient(String host, int port, int count) {
        this.host = host;
        this.port = port;
        this.count = count;
    }

    public void run() throws Exception {
        EventLoopGroup group = new NioEventLoopGroup();
        try {
            Bootstrap b = new Bootstrap();
            b.group(group)
             .channel(NioSocketChannel.class)
             .handler(new FactorialClientInitializer(count));

            // Make a new connection.
            ChannelFuture f = b.connect(host, port).sync();

            // Get the handler instance to retrieve the answer.
            FactorialClientHandler handler =
                (FactorialClientHandler) f.channel().pipeline().last();

            // Print out the answer.
            System.err.format(
                    "Factorial of %,d is: %,d", count, handler.getFactorial());
        } finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        // Print usage if no argument is specified.
        if (args.length != 3) {
            System.err.println(
                    "Usage: " + FactorialClient.class.getSimpleName() +
                    " <host> <port> <count>");
            return;
        }

        // Parse options.
        String host = args[0];
        int port = Integer.parseInt(args[1]);
        int count = Integer.parseInt(args[2]);
        if (count <= 0) {
            throw new IllegalArgumentException("count must be a positive integer.");
        }

        new FactorialClient(host, port, count).run();
    }
}