Add months to a date in groovy

Question

I am trying to add dynamic number of months to a date using groovy. I have tried it using TimeCategory.

I have tried as mentioned in the blog here - [https://stackoverflow.com/questions/31707460/how-to-add-year-or-months-from-current-date-in-groovy] However my below code dosent return correct output. Need help to figure out what's wrong with my code.

My Input - CurrentRunDate = 2022-09-19, additionalmonths = 5

Current output from above code - MM/dd/yyyy5 months

import com.sap.it.api.mapping.*;
import java.text.SimpleDateFormat;
import groovy.time.TimeCategory

def String AddMonthsToDate(String CurrentRunDate, int additionalmonths){
    def emptydate = "";
    if(CurrentRunDate == "")
    {
        return emptydate;
    }
    else
    {
 
    use(TimeCategory) {
    def currentdate = CurrentRunDate.format("MM/dd/yyyy")
    def addmonths = currentdate + additionalmonths.month
    return addmonths

    }
}}

Answer 1

The issue here is that you are not converting CurrentRunDate into a Date object before using it with TimeCategory. You need to parse the date string, add the months you want, and then convert the Date back into a String to return.

In essence, you'll want something similar to this:

import java.text.SimpleDateFormat
import groovy.time.TimeCategory

String addMonthsToDate(String currentRunDate, int additionalMonths) {
    // validate currentRunDate as being present and truthy
    if (!currentRunDate) {
        return ""
    }

    // lets set up our simple date format object for parsing and formating
    def sdf = new SimpleDateFormat("MM/dd/yyyy")

    // using that formmater let's parse the date string into a date obj
    def parsedDate = sdf.parse(currentRunDate)

    // let's now use that date obj in the TimeCategory body 
    def datePlusOneMonth = use(TimeCategory) { parsedDate + additionalMonths.month }

    // let's convert back to a string 
    return sdf.format(datePlusOneMonth)
}

As a test:

assert addMonthsToDate("01/01/2000", 1) == "02/01/2000"