Class NTPUDPClient

java.lang.Object
org.apache.commons.net.DatagramSocketClient
org.apache.commons.net.ntp.NTPUDPClient
All Implemented Interfaces:
AutoCloseable

public final class NTPUDPClient extends DatagramSocketClient
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.
  • Field Details

  • Constructor Details

  • Method Details

    • getTime

      public TimeInfo getTime(InetAddress host) throws IOException
      Retrieves 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.
    • getTime

      public TimeInfo getTime(InetAddress host, int port) throws IOException
      Retrieves 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.
    • getVersion

      public int getVersion()
      Returns 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:
    • setVersion

      public void setVersion(int version)
      Sets the NTP protocol version number that client sets on request packet communicate with remote host.
      Parameters:
      version - the NTP protocol version number