@FromString
    public static Minutes parseMinutes(String periodStr) {
        if (periodStr == null) {
            return Minutes.ZERO;
        }
        Period p = PARSER.parsePeriod(periodStr);
        return Minutes.minutes(p.getMinutes());
    }
@ FromString public static Minutes parseMinutes ( String periodStr ) { if ( periodStr == null ) { return Minutes . ZERO ; } Period p = PARSER . parsePeriod ( periodStr ) ; return Minutes . minutes ( p . getMinutes ( ) ) ; }
Creates a new <code>Minutes</code> by parsing a string in the ISO8601 format 'PTnM'.
<p>
The parse will accept the full ISO syntax of PnYnMnWnDTnHnMnS however only the
minutes component may be non-zero. If any other component is non-zero, an exception
will be thrown.

@param periodStr  the period string, null returns zero
@return the period in minutes
@throws IllegalArgumentException if the string format is invalid