Parse multiple date string formats

MultiDateFormat.groovy

import java.text.DateFormat
import java.text.FieldPosition
import java.text.NumberFormat
import java.text.ParsePosition
import java.text.SimpleDateFormat

class MultiDateFormat extends DateFormat {
    private final SimpleDateFormat printer
    private final List<SimpleDateFormat> parsers

    MultiDateFormat(
            String printFormat, List<String> readFormats) {
        super()
        calendar = Calendar.instance
        numberFormat = NumberFormat.instance
        printer = new SimpleDateFormat(printFormat)
        parsers = readFormats.collect { new SimpleDateFormat(it) }
    }

    @Override
    StringBuffer format(
            Date date, StringBuffer toAppendTo, FieldPosition fieldPosition) {
        printer.format(date, toAppendTo, fieldPosition)
    }

    @Override
    Date parse(String source, ParsePosition pos) {
        parsers.findResult { it.parse(source, pos) }
    }
}