Class Utils

netty/src/main/java/io/grpc/netty/Utils.java:78–604

Common utility methods.

 * Common utility methods.
 */
class Utils {
  private static final Logger logger = Logger.getLogger(Utils.class.getName());

  public static final AsciiString STATUS_OK = AsciiString.of("200");
  public static final AsciiString HTTP_METHOD = AsciiString.of(GrpcUtil.HTTP_METHOD);
  public static final AsciiString HTTP_GET_METHOD = AsciiString.of("GET");
  public static final AsciiString HTTPS = AsciiString.of("https");
  public static final AsciiString HTTP = AsciiString.of("http");
  public static final AsciiString CONTENT_TYPE_HEADER = AsciiString.of(CONTENT_TYPE_KEY.name());
  public static final AsciiString CONTENT_TYPE_GRPC = AsciiString.of(GrpcUtil.CONTENT_TYPE_GRPC);
  public static final AsciiString TE_HEADER = AsciiString.of(GrpcUtil.TE_HEADER.name());
  public static final AsciiString TE_TRAILERS = AsciiString.of(GrpcUtil.TE_TRAILERS);
  public static final AsciiString USER_AGENT = AsciiString.of(GrpcUtil.USER_AGENT_KEY.name());
  public static final Resource<EventLoopGroup> NIO_BOSS_EVENT_LOOP_GROUP
      = new DefaultEventLoopGroupResource(1, "grpc-nio-boss-ELG", EventLoopGroupType.NIO);
  public static final Resource<EventLoopGroup> NIO_WORKER_EVENT_LOOP_GROUP
      = new DefaultEventLoopGroupResource(0, "grpc-nio-worker-ELG", EventLoopGroupType.NIO);
  private static final int HEADER_ENTRY_OVERHEAD = 32;
  private static final byte[] binaryHeaderSuffixBytes =
      Metadata.BINARY_HEADER_SUFFIX.getBytes(US_ASCII);
  public static final Resource<EventLoopGroup> DEFAULT_BOSS_EVENT_LOOP_GROUP;
  public static final Resource<EventLoopGroup> DEFAULT_WORKER_EVENT_LOOP_GROUP;

  // This class is initialized on first use, thus provides delayed allocator creation.
  private static final class ByteBufAllocatorPreferDirectHolder {
    private static final ByteBufAllocator allocator = createByteBufAllocator(true);
  }

  // This class is initialized on first use, thus provides delayed allocator creation.
  private static final class ByteBufAllocatorPreferHeapHolder {
    private static final ByteBufAllocator allocator = createByteBufAllocator(false);
  }

  public static final ChannelFactory<? extends ServerChannel> DEFAULT_SERVER_CHANNEL_FACTORY;
  public static final Class<? extends Channel> DEFAULT_CLIENT_CHANNEL_TYPE;
  public static final Class<? extends Channel> EPOLL_DOMAIN_CLIENT_CHANNEL_TYPE;

  @Nullable
  private static final Constructor<? extends EventLoopGroup> EPOLL_EVENT_LOOP_GROUP_CONSTRUCTOR;

  static {
    // Decide default channel types and EventLoopGroup based on Epoll availability
    if (isEpollAvailable()) {
      DEFAULT_CLIENT_CHANNEL_TYPE = epollChannelType();
      EPOLL_DOMAIN_CLIENT_CHANNEL_TYPE = epollDomainSocketChannelType();
      DEFAULT_SERVER_CHANNEL_FACTORY = new ReflectiveChannelFactory<>(epollServerChannelType());
      EPOLL_EVENT_LOOP_GROUP_CONSTRUCTOR = epollEventLoopGroupConstructor();
      DEFAULT_BOSS_EVENT_LOOP_GROUP = new DefaultEventLoopGroupResource(
          1, "grpc-default-boss-ELG", EventLoopGroupType.EPOLL);
      DEFAULT_WORKER_EVENT_LOOP_GROUP = new DefaultEventLoopGroupResource(
          0, "grpc-default-worker-ELG", EventLoopGroupType.EPOLL);
    } else {
      logger.log(Level.FINE, "Epoll is not available, using Nio.", getEpollUnavailabilityCause());
      DEFAULT_SERVER_CHANNEL_FACTORY = nioServerChannelFactory();
      DEFAULT_CLIENT_CHANNEL_TYPE = NioSocketChannel.class;
      EPOLL_DOMAIN_CLIENT_CHANNEL_TYPE = null;
      DEFAULT_BOSS_EVENT_LOOP_GROUP = NIO_BOSS_EVENT_LOOP_GROUP;
      DEFAULT_WORKER_EVENT_LOOP_GROUP = NIO_WORKER_EVENT_LOOP_GROUP;