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 the 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
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

java.lang.String toString()
Converts the DATETIME value to a String object representing a datetime in the format YYYY-MM-DD hh:mm:ss.fff.
static FglDateTime valueOf(
  long milliseconds)

Creates a new FglDateTime object representing the specified number of milliseconds since the standard base time known as "the epoch", namely January 1, 1970, 00:00:00 GMT.

static FglDateTime valueOf(
  java.lang.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 FglDateTime valueOf(
  java.lang.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.
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 a 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
  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()

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.