CharGenUDPClient (Apache Commons Net 3.5 API)

java.lang.Object
- org.apache.commons.net.DatagramSocketClient
- - org.apache.commons.net.chargen.CharGenUDPClient

```
public final class CharGenUDPClient
extends DatagramSocketClient
```
The CharGenUDPClient class is a UDP implementation of a client for the character generator protocol described in RFC 864. It can also be used for Systat (RFC 866), Quote of the Day (RFC 865), and netstat (port 15). All of these protocols involve sending a datagram to the appropriate port, and reading data contained in one or more reply datagrams. The chargen and quote of the day protocols only send one reply datagram containing 512 bytes or less of data. The other protocols may reply with more than one datagram, in which case you must wait for a timeout to determine that all reply datagrams have been sent.
To use the CharGenUDPClient class, just open a local UDP port with open and call send to send the datagram that will initiate the data reply. For chargen or quote of the day, just call receive , and you're done. For netstat and systat, call receive in a while loop, and catch a SocketException and InterruptedIOException to detect a timeout (don't forget to set the timeout duration beforehand). Don't forget to call close() to clean up properly.

See Also:
CharGenTCPClient

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`CHARGEN_PORT` The character generator port value of 19 according to RFC 864.
`static int`	`DEFAULT_PORT` The default chargen port.
`static int`	`NETSTAT_PORT` The netstat port value of 19.
`static int`	`QUOTE_OF_DAY_PORT` The quote of the day port value of 17 according to RFC 865.
`static int`	`SYSTAT_PORT` The systat port value of 11 according to RFC 866.

Fields inherited from class org.apache.commons.net.DatagramSocketClient
_isOpen_, _socket_, _socketFactory_, _timeout_

Constructor Summary

Constructors
Constructor and Description

CharGenUDPClient()
The default CharGenUDPClient constructor.

Constructors
Constructor and Description
`CharGenUDPClient()` The default CharGenUDPClient constructor.

Method Summary

Methods
Modifier and Type	Method and Description
`byte[]`	`receive()` Receive the reply data from the server.
`void`	`send(InetAddress host)` Same as `send(host, CharGenUDPClient.DEFAULT_PORT);`
`void`	`send(InetAddress host, int port)` Sends the data initiation datagram.

Methods inherited from class org.apache.commons.net.DatagramSocketClient
close, getCharset, getCharsetName, getDefaultTimeout, getLocalAddress, getLocalPort, getSoTimeout, isOpen, open, open, open, setCharset, setDatagramSocketFactory, setDefaultTimeout, setSoTimeout

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - SYSTAT_PORT
```
public static final int SYSTAT_PORT
```
    The systat port value of 11 according to RFC 866.
    
    See Also:
    Constant Field Values
  - NETSTAT_PORT
```
public static final int NETSTAT_PORT
```
    The netstat port value of 19.
    
    See Also:
    Constant Field Values
  - QUOTE_OF_DAY_PORT
```
public static final int QUOTE_OF_DAY_PORT
```
    The quote of the day port value of 17 according to RFC 865.
    
    See Also:
    Constant Field Values
  - CHARGEN_PORT
```
public static final int CHARGEN_PORT
```
    The character generator port value of 19 according to RFC 864.
    
    See Also:
    Constant Field Values
  - DEFAULT_PORT
```
public static final int DEFAULT_PORT
```
    The default chargen port. It is set to 19 according to RFC 864.
    
    See Also:
    Constant Field Values
- Constructor Detail
  - CharGenUDPClient
```
public CharGenUDPClient()
```
    The default CharGenUDPClient constructor. It initializes some internal data structures for sending and receiving the necessary datagrams for the chargen and related protocols.
- Method Detail
  - send
```
public void send(InetAddress host,
        int port)
          throws IOException
```
    Sends the data initiation datagram. This data in the packet is ignored by the server, and merely serves to signal that the server should send its reply.
    
    Parameters:
    host - The address of the server.
    port - The port of the service.
    
    Throws:
    
    IOException - If an error occurs while sending the datagram.
  - send
```
public void send(InetAddress host)
          throws IOException
```
    Same as send(host, CharGenUDPClient.DEFAULT_PORT);
    
    Parameters:
    host - the destination host
    
    Throws:
    
    IOException - on error
  - receive
```
public byte[] receive()
               throws IOException
```
    Receive the reply data from the server. This will always be 512 bytes or less. Chargen and quote of the day only return one packet. Netstat and systat require multiple calls to receive() with timeout detection.
    
    Returns:
    The reply data from the server.
    
    Throws:
    
    IOException - If an error occurs while receiving the datagram.

Class CharGenUDPClient

Field Summary

Fields inherited from class org.apache.commons.net.DatagramSocketClient

Constructor Summary

Method Summary

Methods inherited from class org.apache.commons.net.DatagramSocketClient

Methods inherited from class java.lang.Object

Field Detail

SYSTAT_PORT

NETSTAT_PORT

QUOTE_OF_DAY_PORT

CHARGEN_PORT

DEFAULT_PORT

Constructor Detail

CharGenUDPClient

Method Detail

send

send

receive