Package examples.ntp
Class SimpleNTPServer
- java.lang.Object
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- examples.ntp.SimpleNTPServer
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- All Implemented Interfaces:
java.lang.Runnable
public class SimpleNTPServer extends java.lang.Object implements java.lang.Runnable
The SimpleNTPServer class is a UDP implementation of a server for the Network Time Protocol (NTP) version 3 as described in RFC 1305. It is a minimal NTP server that doesn't actually adjust the time but only responds to NTP datagram requests with response sent back to originating host with info filled out using the current clock time. To be used for debugging or testing. To prevent this from interfering with the actual NTP service it can be run from any local port.
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Constructor Summary
Constructors Constructor Description SimpleNTPServer()
Create SimpleNTPServer listening on default NTP port.SimpleNTPServer(int port)
Create SimpleNTPServer.
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Method Summary
All Methods Static Methods Instance Methods Concrete Methods Modifier and Type Method Description void
connect()
Connect to server socket and listen for client connections.int
getPort()
protected void
handlePacket(java.net.DatagramPacket request, long rcvTime)
Handle incoming packet.boolean
isRunning()
Return state of whether time service is running.boolean
isStarted()
Return state of whether time service is running.static void
main(java.lang.String[] args)
void
run()
main thread to service client connections.void
start()
Start time service and provide time to client connections.void
stop()
Close server socket and stop listening.
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Constructor Detail
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SimpleNTPServer
public SimpleNTPServer()
Create SimpleNTPServer listening on default NTP port.
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SimpleNTPServer
public SimpleNTPServer(int port)
Create SimpleNTPServer.- Parameters:
port
- the local port the server socket is bound to, orzero
for a system selected free port.- Throws:
java.lang.IllegalArgumentException
- if port number less than 0
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Method Detail
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getPort
public int getPort()
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isRunning
public boolean isRunning()
Return state of whether time service is running.- Returns:
- true if time service is running
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isStarted
public boolean isStarted()
Return state of whether time service is running.- Returns:
- true if time service is running
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connect
public void connect() throws java.io.IOException
Connect to server socket and listen for client connections.- Throws:
java.io.IOException
- if an I/O error occurs when creating the socket.
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start
public void start() throws java.io.IOException
Start time service and provide time to client connections.- Throws:
java.io.IOException
- if an I/O error occurs when creating the socket.
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run
public void run()
main thread to service client connections.- Specified by:
run
in interfacejava.lang.Runnable
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handlePacket
protected void handlePacket(java.net.DatagramPacket request, long rcvTime) throws java.io.IOException
Handle incoming packet. If NTP packet is client-mode then respond to that host with a NTP response packet otherwise ignore.- Parameters:
request
- incoming DatagramPacketrcvTime
- time packet received- Throws:
java.io.IOException
- if an I/O error occurs.
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stop
public void stop()
Close server socket and stop listening.
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main
public static void main(java.lang.String[] args)
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