| package org.apache.commons.net.ntp; |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| |
| |
| import java.text.DateFormat; |
| import java.text.SimpleDateFormat; |
| import java.util.Date; |
| import java.util.Locale; |
| import java.util.TimeZone; |
| |
| /*** |
| * 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. |
| * <p> |
| * 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. |
| * </p> |
| * |
| * @version $Revision$ |
| * @see java.util.Date |
| */ |
| public class TimeStamp implements java.io.Serializable, Comparable<TimeStamp> |
| { |
| private static final long serialVersionUID = 8139806907588338737L; |
| |
| /** |
| * baseline NTP time if bit-0=0 is 7-Feb-2036 @ 06:28:16 UTC |
| */ |
| protected static final long msb0baseTime = 2085978496000L; |
| |
| /** |
| * baseline NTP time if bit-0=1 is 1-Jan-1900 @ 01:00:00 UTC |
| */ |
| protected static final long msb1baseTime = -2208988800000L; |
| |
| /** |
| * Default NTP date string format. E.g. Fri, Sep 12 2003 21:06:23.860. |
| * See <code>java.text.SimpleDateFormat</code> for code descriptions. |
| */ |
| public static final String NTP_DATE_FORMAT = "EEE, MMM dd yyyy HH:mm:ss.SSS"; |
| |
| /** |
| * NTP timestamp value: 64-bit unsigned fixed-point number as defined in RFC-1305 |
| * with high-order 32 bits the seconds field and the low-order 32-bits the |
| * fractional field. |
| */ |
| private final long ntpTime; |
| |
| private DateFormat simpleFormatter; |
| private DateFormat utcFormatter; |
| |
| // initialization of static time bases |
| /* |
| static { |
| TimeZone utcZone = TimeZone.getTimeZone("UTC"); |
| Calendar calendar = Calendar.getInstance(utcZone); |
| calendar.set(1900, Calendar.JANUARY, 1, 0, 0, 0); |
| calendar.set(Calendar.MILLISECOND, 0); |
| msb1baseTime = calendar.getTime().getTime(); |
| calendar.set(2036, Calendar.FEBRUARY, 7, 6, 28, 16); |
| calendar.set(Calendar.MILLISECOND, 0); |
| msb0baseTime = calendar.getTime().getTime(); |
| } |
| */ |
| |
| /*** |
| * Constructs a newly allocated NTP timestamp object |
| * that represents the native 64-bit long argument. |
| * @param ntpTime the timestamp |
| */ |
| public TimeStamp(long ntpTime) |
| { |
| this.ntpTime = ntpTime; |
| } |
| |
| /*** |
| * Constructs a newly allocated NTP timestamp object |
| * that represents the value represented by the string |
| * in hexdecimal form (e.g. "c1a089bd.fc904f6d"). |
| * @param hexStamp the hex timestamp |
| * |
| * @throws NumberFormatException - if the string does not contain a parsable timestamp. |
| */ |
| public TimeStamp(String hexStamp) throws NumberFormatException |
| { |
| ntpTime = decodeNtpHexString(hexStamp); |
| } |
| |
| /*** |
| * Constructs a newly allocated NTP timestamp object |
| * that represents the Java Date argument. |
| * |
| * @param d - the Date to be represented by the Timestamp object. |
| */ |
| public TimeStamp(Date d) |
| { |
| ntpTime = (d == null) ? 0 : toNtpTime(d.getTime()); |
| } |
| |
| /*** |
| * Returns the value of this Timestamp as a long value. |
| * |
| * @return the 64-bit long value represented by this object. |
| */ |
| public long ntpValue() |
| { |
| return ntpTime; |
| } |
| |
| /*** |
| * Returns high-order 32-bits representing the seconds of this NTP timestamp. |
| * |
| * @return seconds represented by this NTP timestamp. |
| */ |
| public long getSeconds() |
| { |
| return (ntpTime >>> 32) & 0xffffffffL; |
| } |
| |
| /*** |
| * Returns low-order 32-bits representing the fractional seconds. |
| * |
| * @return fractional seconds represented by this NTP timestamp. |
| */ |
| public long getFraction() |
| { |
| return ntpTime & 0xffffffffL; |
| } |
| |
| /*** |
| * Convert NTP timestamp to Java standard time. |
| * |
| * @return NTP Timestamp in Java time |
| */ |
| public long getTime() |
| { |
| return getTime(ntpTime); |
| } |
| |
| /*** |
| * Convert NTP timestamp to Java Date object. |
| * |
| * @return NTP Timestamp in Java Date |
| */ |
| public Date getDate() |
| { |
| long time = getTime(ntpTime); |
| return new Date(time); |
| } |
| |
| /*** |
| * 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. |
| * |
| * @param ntpTimeValue the input time |
| * @return the number of milliseconds since January 1, 1970, 00:00:00 GMT |
| * represented by this NTP timestamp value. |
| */ |
| public static long getTime(long ntpTimeValue) |
| { |
| long seconds = (ntpTimeValue >>> 32) & 0xffffffffL; // high-order 32-bits |
| long fraction = ntpTimeValue & 0xffffffffL; // low-order 32-bits |
| |
| // Use round-off on fractional part to preserve going to lower precision |
| fraction = Math.round(1000D * fraction / 0x100000000L); |
| |
| /* |
| * If the most significant bit (MSB) on the seconds field is set we use |
| * a different time base. The following text is a quote from RFC-2030 (SNTP v4): |
| * |
| * If bit 0 is set, the UTC time is in the range 1968-2036 and UTC time |
| * is reckoned from 0h 0m 0s UTC on 1 January 1900. If bit 0 is not set, |
| * the time is in the range 2036-2104 and UTC time is reckoned from |
| * 6h 28m 16s UTC on 7 February 2036. |
| */ |
| long msb = seconds & 0x80000000L; |
| if (msb == 0) { |
| // use base: 7-Feb-2036 @ 06:28:16 UTC |
| return msb0baseTime + (seconds * 1000) + fraction; |
| } else { |
| // use base: 1-Jan-1900 @ 01:00:00 UTC |
| return msb1baseTime + (seconds * 1000) + fraction; |
| } |
| } |
| |
| /*** |
| * 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. |
| * @param date the milliseconds since January 1, 1970, 00:00:00 GMT. |
| * @return NTP timestamp object at the specified date. |
| */ |
| public static TimeStamp getNtpTime(long date) |
| { |
| return new TimeStamp(toNtpTime(date)); |
| } |
| |
| /*** |
| * Constructs a NTP timestamp object and initializes it so that |
| * it represents the time at which it was allocated, measured to the |
| * nearest millisecond. |
| * @return NTP timestamp object set to the current time. |
| * @see java.lang.System#currentTimeMillis() |
| */ |
| public static TimeStamp getCurrentTime() |
| { |
| return getNtpTime(System.currentTimeMillis()); |
| } |
| |
| /*** |
| * Convert NTP timestamp hexstring (e.g. "c1a089bd.fc904f6d") to the NTP |
| * 64-bit unsigned fixed-point number. |
| * @param hexString the string to convert |
| * |
| * @return NTP 64-bit timestamp value. |
| * @throws NumberFormatException - if the string does not contain a parsable timestamp. |
| */ |
| protected static long decodeNtpHexString(String hexString) |
| throws NumberFormatException |
| { |
| if (hexString == null) { |
| throw new NumberFormatException("null"); |
| } |
| int ind = hexString.indexOf('.'); |
| if (ind == -1) { |
| if (hexString.length() == 0) { |
| return 0; |
| } |
| return Long.parseLong(hexString, 16) << 32; // no decimal |
| } |
| |
| return Long.parseLong(hexString.substring(0, ind), 16) << 32 | |
| Long.parseLong(hexString.substring(ind + 1), 16); |
| } |
| |
| /*** |
| * Parses the string argument as a NTP hexidecimal timestamp representation string |
| * (e.g. "c1a089bd.fc904f6d"). |
| * |
| * @param s - hexstring. |
| * @return the Timestamp represented by the argument in hexidecimal. |
| * @throws NumberFormatException - if the string does not contain a parsable timestamp. |
| */ |
| public static TimeStamp parseNtpString(String s) |
| throws NumberFormatException |
| { |
| return new TimeStamp(decodeNtpHexString(s)); |
| } |
| |
| /*** |
| * Converts Java time to 64-bit NTP time representation. |
| * |
| * @param t Java time |
| * @return NTP timestamp representation of Java time value. |
| */ |
| protected static long toNtpTime(long t) |
| { |
| boolean useBase1 = t < msb0baseTime; // time < Feb-2036 |
| long baseTime; |
| if (useBase1) { |
| baseTime = t - msb1baseTime; // dates <= Feb-2036 |
| } else { |
| // if base0 needed for dates >= Feb-2036 |
| baseTime = t - msb0baseTime; |
| } |
| |
| long seconds = baseTime / 1000; |
| long fraction = ((baseTime % 1000) * 0x100000000L) / 1000; |
| |
| if (useBase1) { |
| seconds |= 0x80000000L; // set high-order bit if msb1baseTime 1900 used |
| } |
| |
| long time = seconds << 32 | fraction; |
| return time; |
| } |
| |
| /*** |
| * Computes a hashcode for this Timestamp. The result is the exclusive |
| * OR of the two halves of the primitive <code>long</code> value |
| * represented by this <code>TimeStamp</code> object. That is, the hashcode |
| * is the value of the expression: |
| * <blockquote><pre> |
| * {@code (int)(this.ntpValue()^(this.ntpValue() >>> 32))} |
| * </pre></blockquote> |
| * |
| * @return a hash code value for this object. |
| */ |
| @Override |
| public int hashCode() |
| { |
| return (int) (ntpTime ^ (ntpTime >>> 32)); |
| } |
| |
| /*** |
| * Compares this object against the specified object. |
| * The result is <code>true</code> if and only if the argument is |
| * not <code>null</code> and is a <code>Long</code> object that |
| * contains the same <code>long</code> value as this object. |
| * |
| * @param obj the object to compare with. |
| * @return <code>true</code> if the objects are the same; |
| * <code>false</code> otherwise. |
| */ |
| @Override |
| public boolean equals(Object obj) |
| { |
| if (obj instanceof TimeStamp) { |
| return ntpTime == ((TimeStamp) obj).ntpValue(); |
| } |
| return false; |
| } |
| |
| /*** |
| * Converts this <code>TimeStamp</code> object to a <code>String</code>. |
| * 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 |
| * |
| * @return NTP timestamp 64-bit long value as hex string with seconds |
| * separated by fractional seconds. |
| */ |
| @Override |
| public String toString() |
| { |
| return toString(ntpTime); |
| } |
| |
| /*** |
| * Left-pad 8-character hex string with 0's |
| * |
| * @param buf - StringBuilder which is appended with leading 0's. |
| * @param l - a long. |
| */ |
| private static void appendHexString(StringBuilder buf, long l) |
| { |
| String s = Long.toHexString(l); |
| for (int i = s.length(); i < 8; i++) { |
| buf.append('0'); |
| } |
| buf.append(s); |
| } |
| |
| /*** |
| * Converts 64-bit NTP timestamp value to a <code>String</code>. |
| * 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 |
| * @param ntpTime the 64 bit timestamp |
| * |
| * @return NTP timestamp 64-bit long value as hex string with seconds |
| * separated by fractional seconds. |
| */ |
| public static String toString(long ntpTime) |
| { |
| StringBuilder buf = new StringBuilder(); |
| // high-order second bits (32..63) as hexstring |
| appendHexString(buf, (ntpTime >>> 32) & 0xffffffffL); |
| |
| // low-order fractional seconds bits (0..31) as hexstring |
| buf.append('.'); |
| appendHexString(buf, ntpTime & 0xffffffffL); |
| |
| return buf.toString(); |
| } |
| |
| /*** |
| * Converts this <code>TimeStamp</code> object to a <code>String</code> |
| * of the form: |
| * <blockquote><pre> |
| * EEE, MMM dd yyyy HH:mm:ss.SSS</pre></blockquote> |
| * See java.text.SimpleDataFormat for code descriptions. |
| * |
| * @return a string representation of this date. |
| */ |
| public String toDateString() |
| { |
| if (simpleFormatter == null) { |
| simpleFormatter = new SimpleDateFormat(NTP_DATE_FORMAT, Locale.US); |
| simpleFormatter.setTimeZone(TimeZone.getDefault()); |
| } |
| Date ntpDate = getDate(); |
| return simpleFormatter.format(ntpDate); |
| } |
| |
| /*** |
| * Converts this <code>TimeStamp</code> object to a <code>String</code> |
| * of the form: |
| * <blockquote><pre> |
| * EEE, MMM dd yyyy HH:mm:ss.SSS UTC</pre></blockquote> |
| * See java.text.SimpleDataFormat for code descriptions. |
| * |
| * @return a string representation of this date in UTC. |
| */ |
| public String toUTCString() |
| { |
| if (utcFormatter == null) { |
| utcFormatter = new SimpleDateFormat(NTP_DATE_FORMAT + " 'UTC'", |
| Locale.US); |
| utcFormatter.setTimeZone(TimeZone.getTimeZone("UTC")); |
| } |
| Date ntpDate = getDate(); |
| return utcFormatter.format(ntpDate); |
| } |
| |
| /*** |
| * Compares two Timestamps numerically. |
| * |
| * @param anotherTimeStamp - the <code>TimeStamp</code> to be compared. |
| * @return the value <code>0</code> if the argument TimeStamp is equal to |
| * this TimeStamp; a value less than <code>0</code> if this TimeStamp |
| * is numerically less than the TimeStamp argument; and a |
| * value greater than <code>0</code> if this TimeStamp is |
| * numerically greater than the TimeStamp argument |
| * (signed comparison). |
| */ |
| // @Override |
| @Override |
| public int compareTo(TimeStamp anotherTimeStamp) |
| { |
| long thisVal = this.ntpTime; |
| long anotherVal = anotherTimeStamp.ntpTime; |
| return (thisVal < anotherVal ? -1 : (thisVal == anotherVal ? 0 : 1)); |
| } |
| |
| } |
