Parsing date strings: some correctly formatted strings return errors

Question

While trying to retrieve day of the week from the string, sometimes an error occurs although the string corresponds to the predefined format.

Below is the function that is used to parse strings and format definition:

val dateFormat = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
def getDayOfWeek(date: String): Int = {
    val stringToParse = date.substring(0, 19)
    try {
      val now = Calendar.getInstance()
      now.setTime(dateFormat.parse(stringToParse))
      println("Correct time string: " + stringToParse)
      now.get(Calendar.DAY_OF_WEEK)
    } catch {
      case _: Throwable => println("Wrong time string: " + stringToParse)
        -1
    } 
}

Below are the examples of successfully/unsuccessfully parsed strings:

Correct time string: 2017-01-01 04:00:00
Wrong time string: 2017-05-04 15:00:00
Correct time string: 2017-01-01 04:00:00
Correct time string: 2017-06-13 07:00:00
Correct time string: 2017-05-04 15:00:00
Correct time string: 2017-01-01 04:00:00
Correct time string: 2017-01-01 04:00:00
Correct time string: 2017-01-01 04:00:00
Correct time string: 2017-01-01 04:00:00
Correct time string: 2017-05-04 15:00:00
Correct time string: 2017-06-13 07:00:00
Correct time string: 2017-05-04 15:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-06-13 07:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-06-13 07:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-01-01 05:00:00
Wrong time string: 2017-06-13 07:00:00
Correct time string: 2017-01-01 05:00:00
Correct time string: 2017-05-04 16:00:00
Correct time string: 2017-05-04 16:00:00

Does anyone know what could cause the error in the above cases? I don't spot any differences between the successful/unsuccessful examples.

Thanks!

Perhaps printing the error message of the exception may help you identify the error more specifically. — stefanobaghino
– stefanobaghino, Commented Jul 6, 2017 at 10:49
I can only support @stefanobaghino as you are correctly parsing "2017-06-13 07:00:00" as well as wrongly. — Luftbaum
– Luftbaum, Commented Jul 6, 2017 at 10:50
One further word of advice: catching Throwable is generally not advisable. You may want to look into the NonFatal extractor, documented here: scala-lang.org/api/2.11.8/… — stefanobaghino
– stefanobaghino, Commented Jul 6, 2017 at 10:51

abstractnature · Accepted Answer · 2017-07-06 12:50:16Z

5

Problem is your SimpleDateFormat is declared globally.

Bring your line

val dateFormat = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss")

inside the function.

SimpleDateFormat is not thread safe, and I assume you must be calling getDayoftheweek() function from outside non-synchronized code.

edited Jul 6, 2017 at 12:50

answered Jul 6, 2017 at 10:56

abstractnature

4562 silver badges9 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Parsing date strings: some correctly formatted strings return errors

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related