Package com.oroinc.net
Class CharGenUDPClient
java.lang.Object
com.oroinc.net.DatagramSocketClient
com.oroinc.net.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.
- Author:
- Daniel F. Savarese
- See Also:
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Field Summary
FieldsModifier and TypeFieldDescriptionstatic final int
The character generator port value of 19 according to RFC 864.static final int
The default chargen port.static final int
The netstat port value of 19.static final int
The quote of the day port value of 17 according to RFC 865.static final int
The systat port value of 11 according to RFC 866.Fields inherited from class com.oroinc.net.DatagramSocketClient
_isOpen_, _socket_, _socketFactory_, _timeout_
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionbyte[]
receive()
Receive the reply data from the server.void
send
(InetAddress host) Same assend(host, CharGenUDPClient.DEFAULT_PORT);
void
send
(InetAddress host, int port) Sends the data initiation datagram.Methods inherited from class com.oroinc.net.DatagramSocketClient
close, getDefaultTimeout, getLocalAddress, getLocalPort, getSoTimeout, isOpen, open, open, open, setDatagramSocketFactory, setDefaultTimeout, setSoTimeout
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Field Details
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SYSTAT_PORT
public static final int SYSTAT_PORTThe systat port value of 11 according to RFC 866.- See Also:
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NETSTAT_PORT
public static final int NETSTAT_PORTThe netstat port value of 19.- See Also:
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QUOTE_OF_DAY_PORT
public static final int QUOTE_OF_DAY_PORTThe quote of the day port value of 17 according to RFC 865.- See Also:
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CHARGEN_PORT
public static final int CHARGEN_PORTThe character generator port value of 19 according to RFC 864.- See Also:
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DEFAULT_PORT
public static final int DEFAULT_PORTThe default chargen port. It is set to 19 according to RFC 864.- See Also:
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Constructor Details
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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.
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Method Details
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send
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.
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send
Same assend(host, CharGenUDPClient.DEFAULT_PORT);
- Throws:
IOException
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receive
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.
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