private boolean isAlphanumericOrPlusMinusPoint(char character) {
        return (character >= 'A' && character <= 'Z') // Unicode A..Z
                || (character >= 'a' && character <= 'z') // Unicode a..z
                || (character >= '0' && character <= '9') // Unicode 0..9
                || character == '+' || character == '-' || character == '.';
    }
Checks whether a given character is in "+-." or an ASCII alphanumeric.
This is useful for a check related to [RFC 2396]

@param character The character to check.
@return <code>true</code> if the character is in "+-." or an ASCII alphanumeric.
src/nu/validator/gnu/xml/aelfred2/SAXDriver.java