org.apache.commons.net.ntp

## Class TimeStamp

- java.lang.Object
- - org.apache.commons.net.ntp.TimeStamp

- All Implemented Interfaces:
    Serializable, Comparable<TimeStamp>

      public class TimeStamp
      extends Object
      implements Serializable, 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 and 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 String` | `NTP_DATE_FORMAT` Default NTP date string format.

  - ### Constructor Summary

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

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `int` | `compareTo(TimeStamp anotherTimeStamp)` Compares two Timestamps numerically.
    `protected static long` | `decodeNtpHexString(String hexString)` Convert NTP timestamp hexstring (e.g.
    `boolean` | `equals(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.
    `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(String s)` Parses the string argument as a NTP hexidecimal timestamp representation string (e.g.
    `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.
    `String` | `toString()` Converts this `TimeStamp` object to a `String`.
    `static String` | `toString(long ntpTime)` Converts 64-bit NTP timestamp value to a `String`.
    `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 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(String hexStamp)
                    throws 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:
        `NumberFormatException` - - if the string does not contain a parsable timestamp.

    - #### TimeStamp

          public TimeStamp(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 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(String hexString)
                                            throws 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:
        `NumberFormatException` - - if the string does not contain a parsable timestamp.

    - #### parseNtpString

          public static TimeStamp parseNtpString(String s)
                                          throws 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:
        `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 `Object`
      Returns:
        a hash code value for this object.

    - #### equals

          public boolean equals(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 `Object`
      Parameters:
        `obj` - the object to compare with.
      Returns:
        `true` if the objects are the same; `false` otherwise.

    - #### toString

          public 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 `Object`
      Returns:
        NTP timestamp 64-bit long value as hex string with seconds separated by fractional seconds.

    - #### toString

          public static 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 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 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 `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).

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