Package org.apache.commons.net.ntp
Class NTPUDPClient
java.lang.Object
org.apache.commons.net.DatagramSocketClient
org.apache.commons.net.ntp.NTPUDPClient
- All Implemented Interfaces:
- AutoCloseable
The NTPUDPClient class is a UDP implementation of a client for the Network Time Protocol (NTP) described in RFC 1305 as well as the Simple Network Time
 Protocol (SNTP) in RFC-2030. To use the class, merely open a local datagram socket with  open  and call  getTime 
 to retrieve the time. Then call  close  to close the connection properly. Successive
 calls to  getTime  are permitted without re-establishing a connection. That is because UDP is a connectionless protocol and the
 Network Time Protocol is stateless.
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Field SummaryFieldsFields inherited from class org.apache.commons.net.DatagramSocketClient_isOpen_, _socket_, _socketFactory_, _timeout_
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Constructor SummaryConstructors
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Method SummaryModifier and TypeMethodDescriptiongetTime(InetAddress host) Retrieves the time information from the specified server on the default NTP port and returns it.getTime(InetAddress host, int port) Retrieves the time information from the specified server and port and returns it.intReturns the NTP protocol version number that client sets on request packet that is sent to remote host (e.g.voidsetVersion(int version) Sets the NTP protocol version number that client sets on request packet communicate with remote host.Methods inherited from class org.apache.commons.net.DatagramSocketClientcheckOpen, close, getCharset, getCharsetName, getDefaultTimeout, getLocalAddress, getLocalPort, getSoTimeout, getSoTimeoutDuration, isOpen, open, open, open, setCharset, setDatagramSocketFactory, setDefaultTimeout, setDefaultTimeout, setSoTimeout, setSoTimeout
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Field Details- 
DEFAULT_PORTThe default NTP port. It is set to 123 according to RFC 1305.- See Also:
 
 
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Constructor Details- 
NTPUDPClientpublic NTPUDPClient()
 
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Method Details- 
getTimeRetrieves the time information from the specified server on the default NTP port and returns it. The time is the number of milliseconds since 00:00 (midnight) 1 January 1900 UTC, as specified by RFC 1305. This method reads the raw NTP packet and constructs a TimeInfo object that allows access to all the fields of the NTP message header.- Parameters:
- host- The address of the server.
- Returns:
- The time value retrieved from the server.
- Throws:
- IOException- If an error occurs while retrieving the time.
 
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getTimeRetrieves the time information from the specified server and port and returns it. The time is the number of milliseconds since 00:00 (midnight) 1 January 1900 UTC, as specified by RFC 1305. This method reads the raw NTP packet and constructs a TimeInfo object that allows access to all the fields of the NTP message header.- Parameters:
- host- The address of the server.
- port- The port of the service.
- Returns:
- The time value retrieved from the server.
- Throws:
- IOException- If an error occurs while retrieving the time or if received packet does not match the request.
 
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getVersionReturns the NTP protocol version number that client sets on request packet that is sent to remote host (e.g. 3=NTP v3, 4=NTP v4, etc.)- Returns:
- the NTP protocol version number that client sets on request packet.
- See Also:
 
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setVersionSets the NTP protocol version number that client sets on request packet communicate with remote host.- Parameters:
- version- the NTP protocol version number
 
 
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