question: public LetterValidator ( @ NonNull final CharSequence errorMessage , @ NonNull final Case caseSensitivity , final boolean allowSpaces , @ NonNull final char ... allowedCharacters ) { super ( errorMessage ) ; setCaseSensitivity ( caseSensitivity ) ; allowSpaces ( allowSpaces ) ; setAllowedCharacters ( allowedCharacters ) ; }
target:  Creates a new validator, which allows to validate texts to ensure, that they only contain letters.