goja-core/src/main/java/goja/core/kits/lang/CharKit.java
public static boolean containsOnlyDigitsAndSigns(String string) {
        int size = string.length();
        for (int i = 0; i < size; i++) {
            char c = string.charAt(i);
            if ((!CharKit.isDigit(c)) && (c != '-') && (c != '+')) {
                return false;
            }
        }
        return true;
    }
public static boolean containsOnlyDigitsAndSigns(String string) {
        int size = string.length();
        for (int i = 0; i < size; i++) {
            char c = string.charAt(i);
            if ((!CharKit.isDigit(c)) && (c != '-') && (c != '+')) {
                return false;
            }
        }
        return true;
    }
Returns <code>true</code> if string {@link #containsOnlyDigits(String) contains only digits}
or signs plus or minus.