question: private String appendNationalNumber ( String nationalNumber ) { int prefixBeforeNationalNumberLength = prefixBeforeNationalNumber . length ( ) ; if ( shouldAddSpaceAfterNationalPrefix && prefixBeforeNationalNumberLength > 0 && prefixBeforeNationalNumber . charAt ( prefixBeforeNationalNumberLength - 1 ) != SEPARATOR_BEFORE_NATIONAL_NUMBER ) { return new String ( prefixBeforeNationalNumber ) + SEPARATOR_BEFORE_NATIONAL_NUMBER + nationalNumber ; } else { return prefixBeforeNationalNumber + nationalNumber ; } }
target:  Combines the national number with any prefix (IDD/+ and country code or national prefix) that was collected. A space will be inserted between them if the current formatting template indicates this to be suitable.