Package io.grpc

Class ClientInterceptors.CheckedForwardingClientCall<ReqT,RespT>

java.lang.Object
io.grpc.ClientCall<ReqT,RespT>
io.grpc.ForwardingClientCall<ReqT,RespT>
io.grpc.ClientInterceptors.CheckedForwardingClientCall<ReqT,RespT>
Enclosing class:
ClientInterceptors
public abstract static class ClientInterceptors.CheckedForwardingClientCall<ReqT,RespT> extends ForwardingClientCall<ReqT,RespT>
A ForwardingClientCall that delivers exceptions from its start logic to the call listener.

ClientCall.start(ClientCall.Listener, Metadata) should not throw any exception other than those caused by misuse, e.g., IllegalStateException. CheckedForwardingClientCall provides checkedStart() in which throwing exceptions is allowed.

  • Constructor Details

    • CheckedForwardingClientCall

      protected CheckedForwardingClientCall(ClientCall<ReqT,RespT> delegate)

  • Method Details

    • checkedStart

      protected abstract void checkedStart(ClientCall.Listener<RespT> responseListener, Metadata headers) throws Exception
      Subclasses implement the start logic here that would normally belong to start().

      Implementation should call this.delegate().start() in the normal path. Exceptions may safely be thrown prior to calling this.delegate().start(). Such exceptions will be handled by CheckedForwardingClientCall and be delivered to responseListener. Exceptions must not be thrown after calling this.delegate().start(), as this can result in ClientCall.Listener.onClose(io.grpc.Status, io.grpc.Metadata) being called multiple times.

      Throws:
      Exception

    • delegate

      protected final ClientCall<ReqT,RespT> delegate()
      Description copied from class: ForwardingClientCall
      Returns the delegated ClientCall.
      Specified by:
      delegate in class ForwardingClientCall<ReqT,RespT>

    • start

      public final void start(ClientCall.Listener<RespT> responseListener, Metadata headers)
      Description copied from class: ClientCall
      Start a call, using responseListener for processing response messages.

      It must be called prior to any other method on this class, except for ClientCall.cancel(java.lang.String, java.lang.Throwable) which may be called at any time.

      Since Metadata is not thread-safe, the caller must not access (read or write) headers after this point.

      Overrides:
      start in class ForwardingClientCall<ReqT,RespT>
      Parameters:
      responseListener - receives response messages
      headers - which can contain extra call metadata, e.g. authentication credentials.

    • request

      public void request(int numMessages)
      Description copied from class: ClientCall
      Requests up to the given number of messages from the call to be delivered to ClientCall.Listener.onMessage(Object). No additional messages will be delivered.

      Message delivery is guaranteed to be sequential in the order received. In addition, the listener methods will not be accessed concurrently. While it is not guaranteed that the same thread will always be used, it is guaranteed that only a single thread will access the listener at a time.

      If it is desired to bypass inbound flow control, a very large number of messages can be specified (e.g. Integer.MAX_VALUE).

      If called multiple times, the number of messages able to delivered will be the sum of the calls.

      This method is safe to call from multiple threads without external synchronization.

      Specified by:
      request in class ClientCall<ReqT,RespT>
      Parameters:
      numMessages - the requested number of messages to be delivered to the listener. Must be non-negative.

    • cancel

      public void cancel(@Nullable String message, @Nullable Throwable cause)
      Description copied from class: ClientCall
      Prevent any further processing for this ClientCall. No further messages may be sent or will be received. The server is informed of cancellations, but may not stop processing the call. Cancellation is permitted even if previously ClientCall.halfClose()d. Cancelling an already cancel()ed ClientCall has no effect.

      No other methods on this class can be called after this method has been called.

      It is recommended that at least one of the arguments to be non-null, to provide useful debug information. Both argument being null may log warnings and result in suboptimal performance. Also note that the provided information will not be sent to the server.

      Specified by:
      cancel in class ClientCall<ReqT,RespT>
      Parameters:
      message - if not null, will appear as the description of the CANCELLED status
      cause - if not null, will appear as the cause of the CANCELLED status

    • halfClose

      public void halfClose()
      Description copied from class: ClientCall
      Close the call for request message sending. Incoming response messages are unaffected. This should be called when no more messages will be sent from the client.
      Specified by:
      halfClose in class ClientCall<ReqT,RespT>

    • setMessageCompression

      public void setMessageCompression(boolean enabled)
      Description copied from class: ClientCall
      Enables per-message compression, if an encoding type has been negotiated. If no message encoding has been negotiated, this is a no-op. By default per-message compression is enabled, but may not have any effect if compression is not enabled on the call.
      Overrides:
      setMessageCompression in class ClientCall<ReqT,RespT>

    • isReady

      public boolean isReady()
      Description copied from class: ClientCall
      If true, indicates that the call is capable of sending additional messages without requiring excessive buffering internally. This event is just a suggestion and the application is free to ignore it, however doing so may result in excessive buffering within the call.

      If false, ClientCall.Listener.onReady() will be called after isReady() transitions to true.

      If the type of the call is either MethodDescriptor.MethodType.UNARY or MethodDescriptor.MethodType.SERVER_STREAMING, this method may persistently return false. Calls that send exactly one message should not check this method.

      This abstract class's implementation always returns true. Implementations generally override the method.

      Overrides:
      isReady in class ClientCall<ReqT,RespT>

    • getAttributes

      public Attributes getAttributes()
      Description copied from class: ClientCall
      Returns additional properties of the call. May only be called after ClientCall.Listener.onHeaders(io.grpc.Metadata) or ClientCall.Listener.onClose(io.grpc.Status, io.grpc.Metadata). If called prematurely, the implementation may throw IllegalStateException or return arbitrary Attributes.
      Overrides:
      getAttributes in class ClientCall<ReqT,RespT>
      Returns:
      non-null attributes

    • toString

      public String toString()
      Overrides:
      toString in class Object