CODEWITHSUNDEEP
javajodatime
user1492226
user1492226

Reputation:

Check date range in java without time AND using jodatime

I have a date supplied by the user and of course today's date. I'm attempting to verify that the difference between the 2 days is at least 2 weeks. I've done this using standard libraries - but I'm attempting to do this using jodaTime and I'm having some difficulty.

// BAD CODE - doesn't work       
// NOTE: getUserSuppliedDate() returns an instance of java.sql.Date
// Also assume that validation prior to this call has been run that 
// validates that the userSuppliedDate comes AFTER today's date - not sure if 
// that is relevant in the context I'm attempting to use these particular jodaTime APIs.
DateTime jodaStartDate = new DateTime(getUserSuppliedDate());
if (Days.daysBetween(jodaStartDate, DateTime.now()).isLessThan(Days.days(14))) {
    System.out.println("Bad user.  You have chosen...poorly.");
}
else {
   System.out.println("Well done user. You have supplied wisely.");
}

// GOOD CODE  ---- ?  Help =)

Upvotes: 0

Views: 47

Answers (1)

Robby Cornelissen
Robby Cornelissen

Reputation: 97130

Your code gives you the wrong result because the dates supplied to Days.daysBetween() are in the wrong order. Since you specified that the user supplied date comes after the current date, your approach will result in a negative number of days.

It will work correctly if you switch the order, putting the earliest date first.

Compare the following two:

DateTime jodaStartDate = new DateTime().withYear(2018)
                                       .withMonthOfYear(7)
                                       .withDayOfMonth(5); // 15 days from now

System.out.println(Days.daysBetween(jodaStartDate, DateTime.now())); // "P-15D"    
System.out.println(Days.daysBetween(DateTime.now(), jodaStartDate)); // "P15D"

In the first case, -15 days will evaluate to less than 14 days.

Using weeks instead of days, you'd run into the same problem:

System.out.println(Weeks.weeksBetween(jodaStartDate, DateTime.now())); // "P-2W"
System.out.println(Weeks.weeksBetween(DateTime.now(), jodaStartDate)); // "P2W"

Upvotes: 1

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