Question

I have a String that looks something like this: “n YEARS n MONTHS n WEEKS n DAYS” (note that the constants may or may not be pluralized)

I need to convert this to either a Joda Period object or an ISO 8601 formatted String (which can in turn be converted to a Period object).

Does anyone have any code, or can they point me to a library to do this?

Update: In case anyone needs to do this, here is the working code. Unfortunately, I had to dynamically build the PeriodFormatterBuilder since the fields were optional. A bit ugly, but it works.

Update2: Fixed error pointed out in comments.

String text = expr1a.getText();
System.out.println(text);

PeriodFormatterBuilder pfb = new PeriodFormatterBuilder().printZeroAlways();

int yearIndex = text.indexOf("YEAR");
int monthIndex = text.indexOf("MONTH");
int weekIndex = text.indexOf("WEEK");
int dayIndex = text.indexOf("DAY");

if (yearIndex > -1) {
  pfb = pfb.appendYears().appendSuffix(" YEAR"," YEARS");
}

if (monthIndex > -1) {
  if (yearIndex > -1) {
    pfb = pfb.appendPrefix(" ").appendMonths().appendSuffix(" MONTH", " MONTHS");
  } else {
    pfb = pfb.appendMonths().appendSuffix(" MONTH", " MONTHS");
  }
} 

if (weekIndex > -1) {
  if (yearIndex > -1 || monthIndex > -1) {
    pfb = pfb.appendPrefix(" ").appendWeeks().appendSuffix(" WEEK", " WEEKS");
  } else {
    pfb = pfb.appendWeeks().appendSuffix(" WEEK", " WEEKS");
  }
}

if (dayIndex > -1) {
  if (yearIndex > -1 || monthIndex > -1 || weekIndex > -1) {
     pfb = pfb.appendPrefix(" ").appendDays().appendSuffix(" DAY"," DAYS");
  } else {
    pfb = pfb.appendDays().appendSuffix(" DAY"," DAYS");
  }
}

PeriodFormatter pf = pfb.toFormatter();

Period period = Period.parse(text, pf);
return period;

Answer 1

You can use the PeriodFormatterBuilder of the joda time API to construct an instance, which parses your format. There is also handling for plurals of the constants.