Method isInteger

src/main/java/com/jdon/util/UtilValidate.java:305–320

Returns true if all characters in string s are numbers. Accepts non-signed integers only. Does not accept floating point, exponential notation, etc.

(String s)

     *  point, exponential notation, etc.
     */
    public static boolean isInteger(String s) {
        if (isEmpty(s)) return defaultEmptyOK;

        // Search through string's characters one by one
        // until we find a non-numeric character.
        // When we do, return false; if we don't, return true.
        for (int i = 0; i < s.length(); i++) {
            // Check that current character is number.
            char c = s.charAt(i);

            if (!isDigit(c)) return false;
        }

        // All characters are numbers.
        return true;
    }

    /** Returns true if all characters are numbers;
     *  first character is allowed to be + or - as well.