Package examples.ntp
Class SimpleNTPServer
java.lang.Object
examples.ntp.SimpleNTPServer
- All Implemented Interfaces:
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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Field Summary
FieldsModifier and TypeFieldDescriptionprivate int
private boolean
private DatagramSocket
private boolean
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Constructor Summary
ConstructorsConstructorDescriptionCreate SimpleNTPServer listening on default NTP port.SimpleNTPServer
(int port) Create SimpleNTPServer. -
Method Summary
Modifier and TypeMethodDescriptionvoid
connect()
Connect to server socket and listen for client connections.int
getPort()
protected void
handlePacket
(DatagramPacket request, long rcvTime) Handle incoming packet.boolean
Return state of whether time service is running.boolean
Return state of whether time service is running.static void
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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Field Details
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port
private int port -
running
private volatile boolean running -
started
private boolean started -
socket
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Constructor Details
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SimpleNTPServer
public SimpleNTPServer()Create SimpleNTPServer listening on default NTP port. -
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:
IllegalArgumentException
- if port number less than 0
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Method Details
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getPort
public int getPort() -
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
Connect to server socket and listen for client connections.- Throws:
IOException
- if an I/O error occurs when creating the socket.
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start
Start time service and provide time to client connections.- Throws:
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. -
handlePacket
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:
IOException
- if an I/O error occurs.
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stop
public void stop()Close server socket and stop listening. -
main
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