Package io.grpc.internal

Class Http2Ping

java.lang.Object
io.grpc.internal.Http2Ping
public class Http2Ping extends Object
Represents an outstanding PING operation on an HTTP/2 channel. This can be used by HTTP/2-based transports to implement ClientTransport.ping(io.grpc.internal.ClientTransport.PingCallback, java.util.concurrent.Executor).

A typical transport need only support one outstanding ping at a time. So, if a ping is requested while an operation is already in progress, the given callback is notified when the existing operation completes.

  • Field Details

    • log

      private static final Logger log

    • data

      private final long data
      The PING frame includes 8 octets of payload data, e.g. 64 bits.

    • stopwatch

      private final com.google.common.base.Stopwatch stopwatch
      Used to measure elapsed time.

    • callbacks

      private Map<ClientTransport.PingCallback,Executor> callbacks
      The registered callbacks and the executor used to invoke them.

    • completed

      private boolean completed
      False until the operation completes, either successfully (other side sent acknowledgement) or unsuccessfully.

    • failureCause

      private Throwable failureCause
      If non-null, indicates the ping failed.

    • roundTripTimeNanos

      private long roundTripTimeNanos
      The round-trip time for the ping, in nanoseconds. This value is only meaningful when completed is true and failureCause is null.

  • Constructor Details

    • Http2Ping

      public Http2Ping(long data, com.google.common.base.Stopwatch stopwatch)
      Creates a new ping operation. The caller is responsible for sending a ping on an HTTP/2 channel using the given payload. The caller is also responsible for starting the stopwatch when the PING frame is sent.
      Parameters:
      data - the ping payload
      stopwatch - a stopwatch for measuring round-trip time

  • Method Details

    • addCallback

      public void addCallback(ClientTransport.PingCallback callback, Executor executor)
      Registers a callback that is invoked when the ping operation completes. If this ping operation is already completed, the callback is invoked immediately.
      Parameters:
      callback - the callback to invoke
      executor - the executor to use

    • payload

      public long payload()
      Returns the expected ping payload for this outstanding operation.
      Returns:
      the expected payload for this outstanding ping

    • complete

      public boolean complete()
      Completes this operation successfully. The stopwatch given during construction is used to measure the elapsed time. Registered callbacks are invoked and provided the measured elapsed time.
      Returns:
      true if the operation is marked as complete; false if it was already complete

    • failed

      public void failed(Throwable failureCause)
      Completes this operation exceptionally. Registered callbacks are invoked and provided the given throwable as the cause of failure.
      Parameters:
      failureCause - the cause of failure

    • notifyFailed

      public static void notifyFailed(ClientTransport.PingCallback callback, Executor executor, Throwable cause)
      Notifies the given callback that the ping operation failed.
      Parameters:
      callback - the callback
      executor - the executor used to invoke the callback
      cause - the cause of failure

    • doExecute

      private static void doExecute(Executor executor, Runnable runnable)
      Executes the given runnable. This prevents exceptions from propagating so that an exception thrown by one callback won't prevent subsequent callbacks from being executed.

    • asRunnable

      private static Runnable asRunnable(ClientTransport.PingCallback callback, long roundTripTimeNanos)
      Returns a runnable that, when run, invokes the given callback, providing the given round-trip duration.

    • asRunnable

      private static Runnable asRunnable(ClientTransport.PingCallback callback, Throwable failureCause)
      Returns a runnable that, when run, invokes the given callback, providing the given cause of failure.