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Timestamp.javaAPI DocJava SE 6 API17088Tue Jun 10 00:25:50 BST 2008java.sql

Timestamp

public class Timestamp extends Date

A thin wrapper around java.util.Date that allows the JDBC API to identify this as an SQL TIMESTAMP value. It adds the ability to hold the SQL TIMESTAMP fractional seconds value, by allowing the specification of fractional seconds to a precision of nanoseconds. A Timestamp also provides formatting and parsing operations to support the JDBC escape syntax for timestamp values.

The precision of a Timestamp object is calculated to be either:

  • 19 , which is the number of characters in yyyy-mm-dd hh:mm:ss
  • 20 + s , which is the number of characters in the yyyy-mm-dd hh:mm:ss.[fff...] and s represents the scale of the given Timestamp, its fractional seconds precision.

Note: This type is a composite of a java.util.Date and a separate nanoseconds value. Only integral seconds are stored in the java.util.Date component. The fractional seconds - the nanos - are separate. The Timestamp.equals(Object) method never returns true when passed an object that isn't an instance of java.sql.Timestamp, because the nanos component of a date is unknown. As a result, the Timestamp.equals(Object) method is not symmetric with respect to the java.util.Date.equals(Object) method. Also, the hashcode method uses the underlying java.util.Date implementation and therefore does not include nanos in its computation.

Due to the differences between the Timestamp class and the java.util.Date class mentioned above, it is recommended that code not view Timestamp values generically as an instance of java.util.Date. The inheritance relationship between Timestamp and java.util.Date really denotes implementation inheritance, and not type inheritance.

Fields Summary
private int
nanos
static final long
serialVersionUID
Constructors Summary
public Timestamp(int year, int month, int date, int hour, int minute, int second, int nano)
Constructs a Timestamp object initialized with the given values.

param
year the year minus 1900
param
month 0 to 11
param
date 1 to 31
param
hour 0 to 23
param
minute 0 to 59
param
second 0 to 59
param
nano 0 to 999,999,999
deprecated
instead use the constructor Timestamp(long millis)
exception
IllegalArgumentException if the nano argument is out of bounds

	super(year, month, date, hour, minute, second);
	if (nano > 999999999 || nano < 0) {
	    throw new IllegalArgumentException("nanos > 999999999 or < 0");
	}
	nanos = nano;
    
public Timestamp(long time)
Constructs a Timestamp object using a milliseconds time value. The integral seconds are stored in the underlying date value; the fractional seconds are stored in the nanos field of the Timestamp object.

param
time milliseconds since January 1, 1970, 00:00:00 GMT. A negative number is the number of milliseconds before January 1, 1970, 00:00:00 GMT.
see
java.util.Calendar

	super((time/1000)*1000);
	nanos = (int)((time%1000) * 1000000);
	if (nanos < 0) {
	    nanos = 1000000000 + nanos;	    
	    super.setTime(((time/1000)-1)*1000);
	}
    
Methods Summary
public booleanafter(java.sql.Timestamp ts)
Indicates whether this Timestamp object is later than the given Timestamp object.

param
ts the Timestamp value to compare with
return
true if this Timestamp object is later; false otherwise

	return compareTo(ts) > 0;
    
public booleanbefore(java.sql.Timestamp ts)
Indicates whether this Timestamp object is earlier than the given Timestamp object.

param
ts the Timestamp value to compare with
return
true if this Timestamp object is earlier; false otherwise

	return compareTo(ts) < 0;
    
public intcompareTo(java.sql.Timestamp ts)
Compares this Timestamp object to the given Timestamp object.

param
ts the Timestamp object to be compared to this Timestamp object
return
the value 0 if the two Timestamp objects are equal; a value less than 0 if this Timestamp object is before the given argument; and a value greater than 0 if this Timestamp object is after the given argument.
since
1.4

        int i = super.compareTo(ts);
        if (i == 0) {
            if (nanos > ts.nanos) {
		    return 1;
            } else if (nanos < ts.nanos) {
                return -1;
            }
        }
        return i;

    
public intcompareTo(java.util.Date o)
Compares this Timestamp object to the given Date, which must be a Timestamp object. If the argument is not a Timestamp object, this method throws a ClassCastException object. (Timestamp objects are comparable only to other Timestamp objects.)

param
o the Date to be compared, which must be a Timestamp object
return
the value 0 if this Timestamp object and the given object are equal; a value less than 0 if this Timestamp object is before the given argument; and a value greater than 0 if this Timestamp object is after the given argument.
since
1.5

       if(o instanceof Timestamp) {
            // When Timestamp instance compare it with a Timestamp
            // Hence it is basically calling this.compareTo((Timestamp))o);
            // Note typecasting is safe because o is instance of Timestamp
           return compareTo((Timestamp)o);
      } else {
            // When Date doing a o.compareTo(this)
            // will give wrong results.
          Timestamp ts = new Timestamp(o.getTime());
          return this.compareTo(ts);
      }
    
public booleanequals(java.lang.Object ts)
Tests to see if this Timestamp object is equal to the given object. This version of the method equals has been added to fix the incorrect signature of Timestamp.equals(Timestamp) and to preserve backward compatibility with existing class files. Note: This method is not symmetric with respect to the equals(Object) method in the base class.

param
ts the Object value to compare with
return
true if the given Object is an instance of a Timestamp that is equal to this Timestamp object; false otherwise

      if (ts instanceof Timestamp) {
	return this.equals((Timestamp)ts);
      } else {
	return false;
      }
    
public booleanequals(java.sql.Timestamp ts)
Tests to see if this Timestamp object is equal to the given Timestamp object.

param
ts the Timestamp value to compare with
return
true if the given Timestamp object is equal to this Timestamp object; false otherwise

	if (super.equals(ts)) {
	    if  (nanos == ts.nanos) {
		return true;
	    } else {
		return false;
	    }
	} else {
	    return false;
	}
    
public intgetNanos()
Gets this Timestamp object's nanos value.

return
this Timestamp object's fractional seconds component
see
#setNanos

	return nanos;
    
public longgetTime()
Returns the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this Timestamp object.

return
the number of milliseconds since January 1, 1970, 00:00:00 GMT represented by this date.
see
#setTime

        long time = super.getTime();
        return (time + (nanos / 1000000));
    
public voidsetNanos(int n)
Sets this Timestamp object's nanos field to the given value.

param
n the new fractional seconds component
exception
java.lang.IllegalArgumentException if the given argument is greater than 999999999 or less than 0
see
#getNanos

	if (n > 999999999 || n < 0) {
	    throw new IllegalArgumentException("nanos > 999999999 or < 0");
	}
	nanos = n;
    
public voidsetTime(long time)
Sets this Timestamp object to represent a point in time that is time milliseconds after January 1, 1970 00:00:00 GMT.

param
time the number of milliseconds.
see
#getTime
see
#Timestamp(long time)
see
java.util.Calendar

	super.setTime((time/1000)*1000);
	nanos = (int)((time%1000) * 1000000);
	if (nanos < 0) {
	    nanos = 1000000000 + nanos;	    
	    super.setTime(((time/1000)-1)*1000);
	}
    
public java.lang.StringtoString()
Formats a timestamp in JDBC timestamp escape format. yyyy-mm-dd hh:mm:ss.fffffffff, where ffffffffff indicates nanoseconds.

return
a String object in yyyy-mm-dd hh:mm:ss.fffffffff format


	int year = super.getYear() + 1900;
	int month = super.getMonth() + 1;
	int day = super.getDate();
	int hour = super.getHours();
	int minute = super.getMinutes();
	int second = super.getSeconds();
	String yearString;
	String monthString;
	String dayString;
	String hourString;
	String minuteString;
	String secondString;
	String nanosString;
	String zeros = "000000000";
	String yearZeros = "0000";
	StringBuffer timestampBuf;

	if (year < 1000) {
	    // Add leading zeros 
	    yearString = "" + year;
	    yearString = yearZeros.substring(0, (4-yearString.length())) + 
	   	yearString;
	} else {
	    yearString = "" + year;
	}
	if (month < 10) {
	    monthString = "0" + month;
	} else {
	    monthString = Integer.toString(month);
	} 
	if (day < 10) {
	    dayString = "0" + day;
	} else {
	    dayString = Integer.toString(day);
	}
	if (hour < 10) {
	    hourString = "0" + hour;
	} else {
	    hourString = Integer.toString(hour);
	}
	if (minute < 10) {
	    minuteString = "0" + minute;
	} else {
	    minuteString = Integer.toString(minute);
	}
	if (second < 10) {
	    secondString = "0" + second;
	} else {
	    secondString = Integer.toString(second);
	}
	if (nanos == 0) {
	    nanosString = "0";
	} else {
	    nanosString = Integer.toString(nanos);

	    // Add leading zeros
	    nanosString = zeros.substring(0, (9-nanosString.length())) +
		nanosString; 

	    // Truncate trailing zeros
	    char[] nanosChar = new char[nanosString.length()];
	    nanosString.getChars(0, nanosString.length(), nanosChar, 0);
	    int truncIndex = 8;
	    while (nanosChar[truncIndex] == '0") {
		truncIndex--;
	    }
	
	    nanosString = new String(nanosChar, 0, truncIndex + 1);
	}

	// do a string buffer here instead.
	timestampBuf = new StringBuffer(20+nanosString.length());
	timestampBuf.append(yearString);
	timestampBuf.append("-");
	timestampBuf.append(monthString);
	timestampBuf.append("-");
	timestampBuf.append(dayString);
	timestampBuf.append(" ");
	timestampBuf.append(hourString);
	timestampBuf.append(":");
	timestampBuf.append(minuteString);
	timestampBuf.append(":");
	timestampBuf.append(secondString);
	timestampBuf.append(".");
	timestampBuf.append(nanosString);
	
	return (timestampBuf.toString());
    
public static java.sql.TimestampvalueOf(java.lang.String s)
Converts a String object in JDBC timestamp escape format to a Timestamp value.

param
s timestamp in format yyyy-mm-dd hh:mm:ss[.f...]. The fractional seconds may be omitted.
return
corresponding Timestamp value
exception
java.lang.IllegalArgumentException if the given argument does not have the format yyyy-mm-dd hh:mm:ss[.f...]

	String date_s;
	String time_s;
	String nanos_s;
	int year;
	int month;
	int day;
	int hour;
	int minute;
	int second;
	int a_nanos = 0;
	int firstDash;
	int secondDash;
	int dividingSpace;
	int firstColon = 0;
	int secondColon = 0;
	int period = 0;
	String formatError = "Timestamp format must be yyyy-mm-dd hh:mm:ss[.fffffffff]";
	String zeros = "000000000";
	String delimiterDate = "-";
	String delimiterTime = ":";
	StringTokenizer stringTokeninzerDate;
	StringTokenizer stringTokeninzerTime;

	if (s == null) throw new java.lang.IllegalArgumentException("null string");

	int counterD = 0;
	int intDate[] = {4,2,2};

	int counterT = 0;
	int intTime[] = {2,2,12};

	// Split the string into date and time components
	s = s.trim();
	dividingSpace = s.indexOf(' ");
	if (dividingSpace > 0) {
	    date_s = s.substring(0,dividingSpace);
	    time_s = s.substring(dividingSpace+1);
	} else {
	    throw new java.lang.IllegalArgumentException(formatError);
	}

	stringTokeninzerTime = new StringTokenizer(time_s, delimiterTime);
	stringTokeninzerDate = new StringTokenizer(date_s, delimiterDate);
	
	while(stringTokeninzerDate.hasMoreTokens()) {
	     String tokenDate = stringTokeninzerDate.nextToken();
	     if(tokenDate.length() != intDate[counterD] ) {
		throw new java.lang.IllegalArgumentException(formatError);
	     }
	     counterD++;	
	}
	
	/*
         //Commenting this portion out for checking of time

	while(stringTokeninzerTime.hasMoreTokens()) {
	     String tokenTime = stringTokeninzerTime.nextToken();
	
	     if	(counterT < 2 && tokenTime.length() != intTime[counterT]  ) {
		throw new java.lang.IllegalArgumentException(formatError);
	     }
	     counterT++;	
	}	     
	*/	  
  
	// Parse the date
	firstDash = date_s.indexOf('-");
	secondDash = date_s.indexOf('-", firstDash+1);

	// Parse the time
	if (time_s == null) 
	    throw new java.lang.IllegalArgumentException(formatError);
	firstColon = time_s.indexOf(':");
	secondColon = time_s.indexOf(':", firstColon+1);
	period = time_s.indexOf('.", secondColon+1);

	// Convert the date
	if ((firstDash > 0) && (secondDash > 0) && 
	    (secondDash < date_s.length()-1)) {
	    year = Integer.parseInt(date_s.substring(0, firstDash)) - 1900;
	    month = 
		Integer.parseInt(date_s.substring
				 (firstDash+1, secondDash)) - 1;
	    day = Integer.parseInt(date_s.substring(secondDash+1));
	} else {		
	    throw new java.lang.IllegalArgumentException(formatError);
	}

	// Convert the time; default missing nanos
	if ((firstColon > 0) & (secondColon > 0) & 
	    (secondColon < time_s.length()-1)) {
	    hour = Integer.parseInt(time_s.substring(0, firstColon));
	    minute = 
		Integer.parseInt(time_s.substring(firstColon+1, secondColon));
	    if ((period > 0) & (period < time_s.length()-1)) {
		second = 
		    Integer.parseInt(time_s.substring(secondColon+1, period));
		nanos_s = time_s.substring(period+1);
		if (nanos_s.length() > 9) 
		    throw new java.lang.IllegalArgumentException(formatError);
		if (!Character.isDigit(nanos_s.charAt(0)))
		    throw new java.lang.IllegalArgumentException(formatError);
		nanos_s = nanos_s + zeros.substring(0,9-nanos_s.length());
		a_nanos = Integer.parseInt(nanos_s);
	    } else if (period > 0) {
		throw new java.lang.IllegalArgumentException(formatError);
	    } else {
		second = Integer.parseInt(time_s.substring(secondColon+1));
	    }
	} else {
	    throw new java.lang.IllegalArgumentException();
	}

	return new Timestamp(year, month, day, hour, minute, second, a_nanos);