DnsResolveContext Class — netty Architecture

Source Code

resolver-dns/src/main/java/io/netty/resolver/dns/DnsResolveContext.java lines 69–1481

abstract class DnsResolveContext<T> {
    private static final InternalLogger logger = InternalLoggerFactory.getInstance(DnsResolveContext.class);
    private static final String PROP_TRY_FINAL_CNAME_ON_ADDRESS_LOOKUPS =
            "io.netty.resolver.dns.tryCnameOnAddressLookups";
    static boolean TRY_FINAL_CNAME_ON_ADDRESS_LOOKUPS;

    static {
        TRY_FINAL_CNAME_ON_ADDRESS_LOOKUPS =
                SystemPropertyUtil.getBoolean(PROP_TRY_FINAL_CNAME_ON_ADDRESS_LOOKUPS, false);

        if (logger.isDebugEnabled()) {
            logger.debug("-D{}: {}", PROP_TRY_FINAL_CNAME_ON_ADDRESS_LOOKUPS, TRY_FINAL_CNAME_ON_ADDRESS_LOOKUPS);
        }
    }

    private static final RuntimeException NXDOMAIN_QUERY_FAILED_EXCEPTION =
            DnsResolveContextException.newStatic("No answer found and NXDOMAIN response code returned",
            DnsResolveContext.class, "onResponse(..)");
    private static final RuntimeException CNAME_NOT_FOUND_QUERY_FAILED_EXCEPTION =
            DnsResolveContextException.newStatic("No matching CNAME record found",
            DnsResolveContext.class, "onResponseCNAME(..)");
    private static final RuntimeException NO_MATCHING_RECORD_QUERY_FAILED_EXCEPTION =
            DnsResolveContextException.newStatic("No matching record type found",
            DnsResolveContext.class, "onResponseAorAAAA(..)");
    private static final RuntimeException UNRECOGNIZED_TYPE_QUERY_FAILED_EXCEPTION =
            DnsResolveContextException.newStatic("Response type was unrecognized",
            DnsResolveContext.class, "onResponse(..)");
    private static final RuntimeException NAME_SERVERS_EXHAUSTED_EXCEPTION =
            DnsResolveContextException.newStatic("No name servers returned an answer",
            DnsResolveContext.class, "tryToFinishResolve(..)");
    private static final RuntimeException SERVFAIL_QUERY_FAILED_EXCEPTION =
            DnsErrorCauseException.newStatic("Query failed with SERVFAIL", SERVFAIL,
                    DnsResolveContext.class, "onResponse(..)");
    private static final RuntimeException NXDOMAIN_CAUSE_QUERY_FAILED_EXCEPTION =
            DnsErrorCauseException.newStatic("Query failed with NXDOMAIN", NXDOMAIN,
                    DnsResolveContext.class, "onResponse(..)");

    final DnsNameResolver parent;
    private final Channel channel;
    private final Promise<?> originalPromise;
    private final DnsServerAddressStream nameServerAddrs;
    private final String hostname;
    private final int dnsClass;
    private final DnsRecordType[] expectedTypes;
    final DnsRecord[] additionals;

    private final Set<Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>> queriesInProgress =
            Collections.newSetFromMap(
                    new IdentityHashMap<Future<AddressedEnvelope<DnsResponse, InetSocketAddress>>, Boolean>());

    private List<T> finalResult;
    private int allowedQueries;
    private boolean triedCNAME;
    private boolean completeEarly;

    DnsResolveContext(DnsNameResolver parent, Channel channel,
                      Promise<?> originalPromise, String hostname, int dnsClass, DnsRecordType[] expectedTypes,
                      DnsRecord[] additionals, DnsServerAddressStream nameServerAddrs, int allowedQueries) {
        assert expectedTypes.length > 0;

        this.parent = parent;
        this.channel = channel;
        this.originalPromise = originalPromise;
        this.hostname = hostname;
        this.dnsClass = dnsClass;
        this.expectedTypes = expectedTypes;
        this.additionals = additionals;

        this.nameServerAddrs = ObjectUtil.checkNotNull(nameServerAddrs, "nameServerAddrs");
        this.allowedQueries = allowedQueries;
    }

    static final class DnsResolveContextException extends RuntimeException {

        private static final long serialVersionUID = 1209303419266433003L;

        private DnsResolveContextException(String message, boolean shared) {
            super(message, null, false, true);
            assert shared;
        }