PreferredAddressTypeComparator Class — netty Architecture

Source Code

resolver-dns/src/main/java/io/netty/resolver/dns/PreferredAddressTypeComparator.java lines 25–54

final class PreferredAddressTypeComparator implements Comparator<InetAddress> {

    private static final PreferredAddressTypeComparator IPv4 = new PreferredAddressTypeComparator(Inet4Address.class);
    private static final PreferredAddressTypeComparator IPv6 = new PreferredAddressTypeComparator(Inet6Address.class);

    static PreferredAddressTypeComparator comparator(SocketProtocolFamily family) {
        switch (family) {
            case INET:
                return IPv4;
            case INET6:
                return IPv6;
            default:
                throw new IllegalArgumentException();
        }
    }

    private final Class<? extends InetAddress> preferredAddressType;

    private PreferredAddressTypeComparator(Class<? extends InetAddress> preferredAddressType) {
        this.preferredAddressType = preferredAddressType;
    }

    @Override
    public int compare(InetAddress o1, InetAddress o2) {
        if (o1.getClass() == o2.getClass()) {
            return 0;
        }
        return preferredAddressType.isAssignableFrom(o1.getClass()) ? -1 : 1;
    }
}