Method isValidName

src/main/java/graphql/Assert.java:245–265

Fast character-by-character validation without regex. Checks if name matches [_A-Za-z][_0-9A-Za-z]

(String name)

     * Checks if name matches [_A-Za-z][_0-9A-Za-z]*
     */
    private static boolean isValidName(String name) {
        if (name.isEmpty()) {
            return false;
        }

        // First character must be [_A-Za-z]
        char first = name.charAt(0);
        if (!(first == '_' || (first >= 'A' && first <= 'Z') || (first >= 'a' && first <= 'z'))) {
            return false;
        }

        // Remaining characters must be [_0-9A-Za-z]
        for (int i = 1; i < name.length(); i++) {
            char c = name.charAt(i);
            if (!(c == '_' || (c >= '0' && c <= '9') || (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'))) {
                return false;
            }
        }

        return true;
    }

    private static <T> T throwAssert(String format, Object... args) {
        throw new AssertException(format(format, args));