Package org.apache.commons.net.ntp

Class TimeStamp

  • All Implemented Interfaces:
    java.io.Serializable, java.lang.Comparable<TimeStamp>
    public class TimeStamp
extends java.lang.Object
implements java.io.Serializable, java.lang.Comparable<TimeStamp>
    TimeStamp class represents the Network Time Protocol (NTP) timestamp as defined in RFC-1305 and SNTP (RFC-2030). It is represented as a 64-bit unsigned fixed-point number in seconds relative to 0-hour on 1-January-1900. The 32-bit low-order bits are the fractional seconds whose precision is about 200 picoseconds. Assumes overflow date when date passes MAX_LONG and reverts back to 0 is 2036 and not 1900. Test for most significant bit: if MSB=0 then 2036 basis is used otherwise 1900 if MSB=1.

    Methods exist to convert NTP timestamps to and from the equivalent Java date representation, which is the number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.

    Version:
    $Revision: 1741829 $
    See Also:
    Date, Serialized Form

    • Field Summary

      Fields 
      Modifier and Type Field Description
      protected static long msb0baseTime
      baseline NTP time if bit-0=0 is 7-Feb-2036 @ 06:28:16 UTC
      protected static long msb1baseTime
      baseline NTP time if bit-0=1 is 1-Jan-1900 @ 01:00:00 UTC
      static java.lang.String NTP_DATE_FORMAT
      Default NTP date string format.

    • Constructor Summary

      Constructors 
      Constructor Description
      TimeStamp​(long ntpTime)
      Constructs a newly allocated NTP timestamp object that represents the native 64-bit long argument.
      TimeStamp​(java.lang.String hexStamp)
      Constructs a newly allocated NTP timestamp object that represents the value represented by the string in hexdecimal form (e.g.
      TimeStamp​(java.util.Date d)
      Constructs a newly allocated NTP timestamp object that represents the Java Date argument.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      int compareTo​(TimeStamp anotherTimeStamp)
      Compares two Timestamps numerically.
      protected static long decodeNtpHexString​(java.lang.String hexString)
      Convert NTP timestamp hexstring (e.g.
      boolean equals​(java.lang.Object obj)
      Compares this object against the specified object.
      static TimeStamp getCurrentTime()
      Constructs a NTP timestamp object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.
      java.util.Date getDate()
      Convert NTP timestamp to Java Date object.
      long getFraction()
      Returns low-order 32-bits representing the fractional seconds.
      static TimeStamp getNtpTime​(long date)
      Helper method to convert Java time to NTP timestamp object.
      long getSeconds()
      Returns high-order 32-bits representing the seconds of this NTP timestamp.
      long getTime()
      Convert NTP timestamp to Java standard time.
      static long getTime​(long ntpTimeValue)
      Convert 64-bit NTP timestamp to Java standard time.
      int hashCode()
      Computes a hashcode for this Timestamp.
      long ntpValue()
      Returns the value of this Timestamp as a long value.
      static TimeStamp parseNtpString​(java.lang.String s)
      Parses the string argument as a NTP hexidecimal timestamp representation string (e.g.
      java.lang.String toDateString()
      Converts this TimeStamp object to a String of the form:
      protected static long toNtpTime​(long t)
      Converts Java time to 64-bit NTP time representation.
      java.lang.String toString()
      Converts this TimeStamp object to a String.
      static java.lang.String toString​(long ntpTime)
      Converts 64-bit NTP timestamp value to a String.
      java.lang.String toUTCString()
      Converts this TimeStamp object to a String of the form:

      • Methods inherited from class java.lang.Object

        clone, finalize, getClass, notify, notifyAll, wait, wait, wait

    • Field Detail

      • msb0baseTime

        protected static final long msb0baseTime
        baseline NTP time if bit-0=0 is 7-Feb-2036 @ 06:28:16 UTC
        See Also:
        Constant Field Values

      • msb1baseTime

        protected static final long msb1baseTime
        baseline NTP time if bit-0=1 is 1-Jan-1900 @ 01:00:00 UTC
        See Also:
        Constant Field Values

      • NTP_DATE_FORMAT

        public static final java.lang.String NTP_DATE_FORMAT
        Default NTP date string format. E.g. Fri, Sep 12 2003 21:06:23.860. See java.text.SimpleDateFormat for code descriptions.
        See Also:
        Constant Field Values

    • Constructor Detail

      • TimeStamp

        public TimeStamp​(long ntpTime)
        Constructs a newly allocated NTP timestamp object that represents the native 64-bit long argument.
        Parameters:
        ntpTime - the timestamp

      • TimeStamp

        public TimeStamp​(java.lang.String hexStamp)
          throws java.lang.NumberFormatException
        Constructs a newly allocated NTP timestamp object that represents the value represented by the string in hexdecimal form (e.g. "c1a089bd.fc904f6d").
        Parameters:
        hexStamp - the hex timestamp
        Throws:
        java.lang.NumberFormatException - - if the string does not contain a parsable timestamp.

      • TimeStamp

        public TimeStamp​(java.util.Date d)
        Constructs a newly allocated NTP timestamp object that represents the Java Date argument.
        Parameters:
        d - - the Date to be represented by the Timestamp object.

    • Method Detail

      • ntpValue

        public long ntpValue()
        Returns the value of this Timestamp as a long value.
        Returns:
        the 64-bit long value represented by this object.

      • getSeconds

        public long getSeconds()
        Returns high-order 32-bits representing the seconds of this NTP timestamp.
        Returns:
        seconds represented by this NTP timestamp.

      • getFraction

        public long getFraction()
        Returns low-order 32-bits representing the fractional seconds.
        Returns:
        fractional seconds represented by this NTP timestamp.

      • getTime

        public long getTime()
        Convert NTP timestamp to Java standard time.
        Returns:
        NTP Timestamp in Java time

      • getDate

        public java.util.Date getDate()
        Convert NTP timestamp to Java Date object.
        Returns:
        NTP Timestamp in Java Date

      • getTime

        public static long getTime​(long ntpTimeValue)
        Convert 64-bit NTP timestamp to Java standard time. Note that java time (milliseconds) by definition has less precision then NTP time (picoseconds) so converting NTP timestamp to java time and back to NTP timestamp loses precision. For example, Tue, Dec 17 2002 09:07:24.810 EST is represented by a single Java-based time value of f22cd1fc8a, but its NTP equivalent are all values ranging from c1a9ae1c.cf5c28f5 to c1a9ae1c.cf9db22c.
        Parameters:
        ntpTimeValue - the input time
        Returns:
        the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this NTP timestamp value.

      • getNtpTime

        public static TimeStamp getNtpTime​(long date)
        Helper method to convert Java time to NTP timestamp object. Note that Java time (milliseconds) by definition has less precision then NTP time (picoseconds) so converting Ntptime to Javatime and back to Ntptime loses precision. For example, Tue, Dec 17 2002 09:07:24.810 is represented by a single Java-based time value of f22cd1fc8a, but its NTP equivalent are all values from c1a9ae1c.cf5c28f5 to c1a9ae1c.cf9db22c.
        Parameters:
        date - the milliseconds since January 1, 1970, 00:00:00 GMT.
        Returns:
        NTP timestamp object at the specified date.

      • getCurrentTime

        public static TimeStamp getCurrentTime()
        Constructs a NTP timestamp object and initializes it so that it represents the time at which it was allocated, measured to the nearest millisecond.
        Returns:
        NTP timestamp object set to the current time.
        See Also:
        System.currentTimeMillis()

      • decodeNtpHexString

        protected static long decodeNtpHexString​(java.lang.String hexString)
                                  throws java.lang.NumberFormatException
        Convert NTP timestamp hexstring (e.g. "c1a089bd.fc904f6d") to the NTP 64-bit unsigned fixed-point number.
        Parameters:
        hexString - the string to convert
        Returns:
        NTP 64-bit timestamp value.
        Throws:
        java.lang.NumberFormatException - - if the string does not contain a parsable timestamp.

      • parseNtpString

        public static TimeStamp parseNtpString​(java.lang.String s)
                                throws java.lang.NumberFormatException
        Parses the string argument as a NTP hexidecimal timestamp representation string (e.g. "c1a089bd.fc904f6d").
        Parameters:
        s - - hexstring.
        Returns:
        the Timestamp represented by the argument in hexidecimal.
        Throws:
        java.lang.NumberFormatException - - if the string does not contain a parsable timestamp.

      • toNtpTime

        protected static long toNtpTime​(long t)
        Converts Java time to 64-bit NTP time representation.
        Parameters:
        t - Java time
        Returns:
        NTP timestamp representation of Java time value.

      • hashCode

        public int hashCode()
        Computes a hashcode for this Timestamp. The result is the exclusive OR of the two halves of the primitive long value represented by this TimeStamp object. That is, the hashcode is the value of the expression: 
         (int)(this.ntpValue()^(this.ntpValue() >>> 32))
        Overrides:
        hashCode in class java.lang.Object
        Returns:
        a hash code value for this object.

      • equals

        public boolean equals​(java.lang.Object obj)
        Compares this object against the specified object. The result is true if and only if the argument is not null and is a Long object that contains the same long value as this object.
        Overrides:
        equals in class java.lang.Object
        Parameters:
        obj - the object to compare with.
        Returns:
        true if the objects are the same; false otherwise.

      • toString

        public java.lang.String toString()
        Converts this TimeStamp object to a String. The NTP timestamp 64-bit long value is represented as hex string with seconds separated by fractional seconds by a decimal point; e.g. c1a089bd.fc904f6d == Tue, Dec 10 2002 10:41:49.986
        Overrides:
        toString in class java.lang.Object
        Returns:
        NTP timestamp 64-bit long value as hex string with seconds separated by fractional seconds.

      • toString

        public static java.lang.String toString​(long ntpTime)
        Converts 64-bit NTP timestamp value to a String. The NTP timestamp value is represented as hex string with seconds separated by fractional seconds by a decimal point; e.g. c1a089bd.fc904f6d == Tue, Dec 10 2002 10:41:49.986
        Parameters:
        ntpTime - the 64 bit timestamp
        Returns:
        NTP timestamp 64-bit long value as hex string with seconds separated by fractional seconds.

      • toDateString

        public java.lang.String toDateString()
        Converts this TimeStamp object to a String of the form: 
         EEE, MMM dd yyyy HH:mm:ss.SSS
        See java.text.SimpleDataFormat for code descriptions.
        Returns:
        a string representation of this date.

      • toUTCString

        public java.lang.String toUTCString()
        Converts this TimeStamp object to a String of the form: 
         EEE, MMM dd yyyy HH:mm:ss.SSS UTC
        See java.text.SimpleDataFormat for code descriptions.
        Returns:
        a string representation of this date in UTC.

      • compareTo

        public int compareTo​(TimeStamp anotherTimeStamp)
        Compares two Timestamps numerically.
        Specified by:
        compareTo in interface java.lang.Comparable<TimeStamp>
        Parameters:
        anotherTimeStamp - - the TimeStamp to be compared.
        Returns:
        the value 0 if the argument TimeStamp is equal to this TimeStamp; a value less than 0 if this TimeStamp is numerically less than the TimeStamp argument; and a value greater than 0 if this TimeStamp is numerically greater than the TimeStamp argument (signed comparison).