public Optional<Character> getOptionalCharacter(String key) {
		return optionalGet(key).map((c) -> {
			if (c.length() != 1) {
				throw new ValidationException("The value of '" + key + "' must only contain one character.");
			}
			return c.charAt(0);
		}
public Optional < Character > getOptionalCharacter ( String key ) { return optionalGet ( key ) . map ( ( c ) -> { if ( c . length ( ) != 1 ) { throw new ValidationException ( "The value of '" + key + "' must only contain one character." ) ; } return c . charAt ( 0 ) ; }
Returns a character value under the given key if it exists.