Using the DATETIME type

When calling a Java™ method with an expression evaluating to a DATETIME, the runtime system converts the DATETIME value to an instance of the com.fourjs.fgl.lang.FglDateTime class implemented in FGLDIR/lib/fgl.jar. You can then manipulate the DATETIME from within the Java code.

You must add FGLDIR/lib/fgl.jar to the class path in order to compile Java code with com.fourjs.fgl.lang.FglDateTime class.

The com.fourjs.fgl.lang.FglDateTime class implements following:
Table 1. Fields of the com.fourjs.fgl.lang.FglDateTime class
Field Description 
final static int YEAR
 Time qualifier for year 
final static int MONTH
 Time qualifier for month 
final static int DAY
 Time qualifier for day 
final static int HOUR
 Time qualifier for hour 
final static int MINUTE
 Time qualifier for minute 
final static int SECOND
 Time qualifier for second 
final static int FRACTION
 Time qualifier for fraction (start qualifier) 
final static int FRACTION1
 Time qualifier for fraction(1) (end qualifier) 
final static int FRACTION2
 Time qualifier for fraction(2) (end qualifier) 
final static int FRACTION3
 Time qualifier for fraction(3) (end qualifier) 
final static int FRACTION4
 Time qualifier for fraction(4) (end qualifier) 
final static int FRACTION5
 Time qualifier for fraction(5) (end qualifier)
Table 2. Methods of the com.fourjs.fgl.lang.FglDateTime class
Method Description 
String toString()
 Converts the DATETIME value to a String object representing a datetime in the format YYYY-MM-DD hh:mm:ss.fff. 
static void valueOf(
  String val)

Creates a new FglDateTime object from a String object representing a datetime value in the format: YYYY-MM-DD hh:mm:ss.fff

 
static void valueOf(
  String val,
  int startUnit, 
  int endUnit)
 Creates a new FglDateTime object from a String object representing a datetime value in the format YYYY-MM-DD hh:mm:ss.fff, using the qualifiers passed as parameter. 
static int encodeTypeQualifier(
  int startUnit, 
  int endUnit)
 Returns the encoded type qualifier for a datetime with to datetime qualifiers passed:

encoded qualifier = (length * 256) + (startUnit * 16) + endUnit

Where length defines the total number of significant digits in this time data.

For example, with DATETIME YEAR TO MINUTE:

startUnit = YEAR

length = 12 (YYYYMMDDhhmm)

endUnit = MINUTE
In the Java code, you can convert the com.fourjs.fgl.lang.FglDateTime to a java.util.Calendar object as in this example:
public static void useDatetime(FglDateTime dt) throws ParseException {
   SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
   Calendar cal = Calendar.getInstance();
   cal.setTime( sdf.parse(dt.toString()) );
   ...
}
If you need to create an com.fourjs.fgl.lang.FglDateTime object in your program, you can use the valueOf() class method as in this example:
IMPORT JAVA com.fourjs.fgl.lang.FglDateTime
MAIN
  DEFINE dt com.fourjs.fgl.lang.FglDateTime
  LET dt = FglDateTime.valueOf("2008-12-23 11:22:33.123")
  LET dt = FglDateTime.valueOf("11:22:33.123",
                FglDateTime.HOUR, FglDateTime.FRACTION3)
  DISPLAY dt.toString()
END MAIN

The valueOf() method expects a string representing a complete date-time specification, from year to milliseconds, equivalent to a DATETIME YEAR TO FRACTION(3) data type.