org.apache.commons.net
Class CharGenUDPClient
public final class CharGenUDPClient
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.
CharGenTCPClient
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.
|
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.
|
close , getDefaultTimeout , getLocalAddress , getLocalPort , getSoTimeout , isOpen , open , open , open , setDatagramSocketFactory , setDefaultTimeout , setSoTimeout |
CHARGEN_PORT
public static final int CHARGEN_PORT
The character generator port value of 19 according to RFC 864. **
- 19
DEFAULT_PORT
public static final int DEFAULT_PORT
The default chargen port. It is set to 19 according to RFC 864. **
- 19
NETSTAT_PORT
public static final int NETSTAT_PORT
The netstat port value of 19. **
- 15
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. **
- 17
SYSTAT_PORT
public static final int SYSTAT_PORT
The systat port value of 11 according to RFC 866. **
- 11
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.
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.
- The reply data from the server.
send
public void send(InetAddress host)
throws IOException
Same as send(host, CharGenUDPClient.DEFAULT_PORT);
**
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.
host
- The address of the server.port
- The port of the service.