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Commons Net example source code file (chargen.java)

This example Commons Net source code file (chargen.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Net tags/keywords

bufferedreader, bufferedreader, chargentcpclient, chargentcpclient, chargenudpclient, chargenudpclient, inetaddress, interruptedioexception, io, ioexception, ioexception, net, network, socketexception, string, timed

The Commons Net chargen.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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 examples.unix;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.InterruptedIOException;
import java.net.InetAddress;
import java.net.SocketException;

import org.apache.commons.net.chargen.CharGenTCPClient;
import org.apache.commons.net.chargen.CharGenUDPClient;

/***
 * This is an example program demonstrating how to use the CharGenTCPClient
 * and CharGenUDPClient classes.  This program connects to the default
 * chargen service port of a specified server, then reads 100 lines from
 * of generated output, writing each line to standard output, and then
 * closes the connection.  The UDP invocation of the program sends 50
 * datagrams, printing the reply to each.
 * The default is to use the TCP port.  Use the -udp flag to use the UDP
 * port.
 * <p>
 * Usage: chargen [-udp] <hostname>
 * <p>
 ***/
public final class chargen
{

    public static final void chargenTCP(String host) throws IOException
    {
        int lines = 100;
        String line;
        CharGenTCPClient client = new CharGenTCPClient();
        BufferedReader chargenInput;

        // We want to timeout if a response takes longer than 60 seconds
        client.setDefaultTimeout(60000);
        client.connect(host);
        chargenInput =
            new BufferedReader(new InputStreamReader(client.getInputStream()));

        // We assume the chargen service outputs lines, but it really doesn't
        // have to, so this code might actually not work if no newlines are
        // present.
        while (lines-- > 0)
        {
            if ((line = chargenInput.readLine()) == null)
                break;
            System.out.println(line);
        }

        client.disconnect();
    }

    public static final void chargenUDP(String host) throws IOException
    {
        int packets = 50;
        byte[] data;
        InetAddress address;
        CharGenUDPClient client;

        address = InetAddress.getByName(host);
        client = new CharGenUDPClient();

        client.open();
        // If we don't receive a return packet within 5 seconds, assume
        // the packet is lost.
        client.setSoTimeout(5000);

        while (packets-- > 0)
        {
            client.send(address);

            try
            {
                data = client.receive();
            }
            // Here we catch both SocketException and InterruptedIOException,
            // because even though the JDK 1.1 docs claim that
            // InterruptedIOException is thrown on a timeout, it seems
            // SocketException is also thrown.
            catch (SocketException e)
            {
                // We timed out and assume the packet is lost.
                System.err.println("SocketException: Timed out and dropped packet");
                continue;
            }
            catch (InterruptedIOException e)
            {
                // We timed out and assume the packet is lost.
                System.err.println(
                    "InterruptedIOException: Timed out and dropped packet");
                continue;
            }
            System.out.write(data);
            System.out.flush();
        }

        client.close();
    }


    public static final void main(String[] args)
    {

        if (args.length == 1)
        {
            try
            {
                chargenTCP(args[0]);
            }
            catch (IOException e)
            {
                e.printStackTrace();
                System.exit(1);
            }
        }
        else if (args.length == 2 && args[0].equals("-udp"))
        {
            try
            {
                chargenUDP(args[1]);
            }
            catch (IOException e)
            {
                e.printStackTrace();
                System.exit(1);
            }
        }
        else
        {
            System.err.println("Usage: chargen [-udp] <hostname>");
            System.exit(1);
        }

    }

}

Other Commons Net examples (source code examples)

Here is a short list of links related to this Commons Net chargen.java source code file:

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