Using DurationCalculator to calculate a due date

Using the DurationCalculator script include, you can calculate the due date, using either a simple duration or relative duration.

The following script demonstrates how to use DurationCalculator to calculate a due date. The first part of the script illustrates how to set a start datetime using the setStartDateTime() method and then use the calcDuration() method to determine a due date that is "x" amount of continuous time (seconds) from the specified start datetime. The second half of the script illustrates how to use DurationCalculator to calculate a due date based on a schedule. Schedules enable you to apply a "filter" on future time, such as only including the days in a work week within the calculation. For example, if you apply a schedule "weekdays" (which only includes Monday through Friday) to your duration calculation, and the start datetime is Friday at 5:00 pm, when you add a duration of two days, your due date would be Tuesday at 5:00 pm. If you did not use a schedule, your due date would be Sunday at 5:00 pm. For additional information on schedules, see Schedules.

This script can be cut and pasted into the Scripts Background page and run as is. It can also serve as an example for authoring business rules, UI actions, or used any other place that server-side script can be authored.
/**
 * Demonstrate the use of DurationCalculator to compute a due date.
 * 
 * You must have a start date and a duration. Then you can compute a
 * due date using the constraints of a schedule.
 */
 
gs.include('DurationCalculator');
executeSample();
 
/**
 * Function to house the sample script.
 */
function executeSample(){
 
    // First we need a DurationCalculator object.
    var dc = new DurationCalculator();
 
    // --------------- No schedule examples ------------------
 
    // Simple computation of a due date without using a schedule. Seconds
    // are added to the start date continuously to get to a due date.
    var gdt = new GlideDateTime("2012-05-01 00:00:00");
    dc.setStartDateTime(gdt);
    if(!dc.calcDuration(2*24*3600)){ // 2 days
      gs.log("*** Error calculating duration");
      return;
    }
    gs.log("calcDuration no schedule: " + dc.getEndDateTime()); // "2012-05-03 00:00:00" two days later
 
    // Start in the middle of the night (2:00 am) and compute a due date 1 hour in the future
    // Without a schedule this yields 3:00 am.
    var gdt = new GlideDateTime("2012-05-03 02:00:00");
    dc.setStartDateTime(gdt);
    if(!dc.calcDuration(3600)){
      gs.log("*** Error calculating duration");
      return;
     }
    gs.log("Middle of night + 1 hour (no schedule): "+ dc.getEndDateTime()); // No scheduled start date, just add 1 hour
 
 
    // -------------- Add a schedule to the date calculator ---------------------
    addSchedule(dc);
 
    // Start in the middle of the night and compute a due date 1 hour in the future.
    // Since we start at 2:00 am the computation adds the 1 hour from the start
    // of the day, 8:00am to get to 9:00am
    var gdt = new GlideDateTime("2012-05-03 02:00:00");
    dc.setStartDateTime(gdt);
    if(!dc.calcDuration(3600)){
      gs.log("*** Error calculating duration");
      return;
    }
    gs.log("Middle of night + 1 hour (with 8-5 schedule): " + dc.getEndDateTime()); // 9:00 am
 
    // Start in the afternoon and add hours beyond quiting time. Our schedule says the work day
    // ends at 5:00pm, if the duration extends beyond that, we roll over to the next work day.
    // In this example we are adding 4 hours to 3:00pm which gives us 10:00 am the next day.
    var gdt = new GlideDateTime("2012-05-03 15:00:00");
    dc.setStartDateTime(gdt);

    if(!dc.calcDuration(4*3600)){ 
      gs.log("*** Error calculating duration");
      return;}
    gs.log("Afternoon + 4 hour (with 8-5 schedule): " + dc.getEndDateTime()); // 10:00 am.
 
    // This is a demo of adding 2 hours repeatedly and examine the result. This
    // is a good way to visualize the result of a due date calculation.
    var gdt = new GlideDateTime("2012-05-03 15:00:00");
    dc.setStartDateTime(gdt); 
    for(var i=2; i<24; i+=1){
      if(!dc.calcDuration(i*3600)){
        gs.log("*** Error calculating duration");
        return;
      }
      gs.log("add "+ i +" hours gives due date: " + dc.getEndDateTime());
    }
 
    // Setting the timezone causes the schedule to be interpreted in the specified timezone.
    // Run the same code as above with different timezone. Note that the 8 to 5 workday is
    // offset by the two hours as specified in our timezone.
    dc.setTimeZone("GMT-2");
    var gdt = new GlideDateTime("2012-05-03 15:00:00");
    dc.setStartDateTime(gdt);
    for(var i=2; i<24; i+=1){
      if(!dc.calcDuration(i*3600)){ 
        gs.log("*** Error calculating duration");
        return;
      }
        gs.log("add "+ i +" hours gives due date (GMT-2): " + dc.getEndDateTime());
    }
}
 
/** 
 * Add a specific schedule to the DurationCalculator object.
 *  
 * @param durationCalculator An instance of DurationCalculator
 */
function addSchedule(durationCalculator){
    // Load the "8-5 weekdays excluding holidays" schedule into our duration calculator.
    var scheduleName = "8-5 weekdays excluding holidays";
    var grSched = new GlideRecord('cmn_schedule');
    grSched.addQuery('name', scheduleName);
    grSched.query();
    if(!grSched.next()){
      gs.log('*** Could not find schedule "'+ scheduleName +'"');
      return;
    }
    durationCalculator.setSchedule(grSched.getUniqueValue(),"GMT");
}

See the ServiceNow Developers site for API information.