Class WsRemoteEndpointImplServer

All Implemented Interfaces:

public class WsRemoteEndpointImplServer extends WsRemoteEndpointImplBase
This is the server side RemoteEndpoint implementation - i.e. what the server uses to send data to the client.
  • Constructor Details

  • Method Details

    • isMasked

      protected final boolean isMasked()
      Specified by:
      isMasked in class WsRemoteEndpointImplBase
    • acquireMessagePartInProgressSemaphore

      protected boolean acquireMessagePartInProgressSemaphore(byte opCode, long timeoutExpiry) throws InterruptedException
      Acquire the semaphore that allows a message part to be written.

      The close message is a special case. It needs to be blocking else implementing the clean-up that follows the sending of the close message gets a lot more complicated. On the server, this creates additional complications as a dead-lock may occur in the following scenario:

      1. Application thread writes message using non-blocking
      2. Write does not complete (write logic holds message pending lock)
      3. Socket is added to poller (or equivalent) for write
      4. Client sends close message
      5. Container processes received close message and tries to send close message in response
      6. Container holds socket lock and is blocked waiting for message pending lock
      7. Poller fires write possible event for socket
      8. Container tries to process write possible event but is blocked waiting for socket lock
      9. Processing of the WebSocket connection is dead-locked until the original message write times out
      The purpose of this method is to break the above dead-lock. It does this by returning control of the processor to the socket wrapper and releasing the socket lock while waiting for the pending message write to complete. Normally, that would be a terrible idea as it creates the possibility that the processor is returned to the pool more than once under various error conditions. In this instance it is safe because these are upgrade processors (isUpgrade() returns true) and upgrade processors are never pooled.

      TODO: Despite the complications it creates, it would be worth exploring the possibility of processing a received close frame in a non-blocking manner.

      acquireMessagePartInProgressSemaphore in class WsRemoteEndpointImplBase
      opCode - The OPCODE for the message to be written
      timeoutExpiry - The time when the attempt to acquire the semaphore should expire
      true if the semaphore is obtained, otherwise false.
      InterruptedException - If the wait for the semaphore is interrupted
    • doWrite

      protected void doWrite(SendHandler handler, long blockingWriteTimeoutExpiry, ByteBuffer... buffers)
      Specified by:
      doWrite in class WsRemoteEndpointImplBase
    • updateStats

      protected void updateStats(long payloadLength)
      Description copied from class: WsRemoteEndpointImplBase
      Hook for updating server side statistics. Called on every frame written (including when batching is enabled and the frames are buffered locally until the buffer is full or is flushed).
      updateStats in class WsRemoteEndpointImplBase
      payloadLength - Size of message payload
    • onWritePossible

      public void onWritePossible(boolean useDispatch)
    • doClose

      protected void doClose()
      Specified by:
      doClose in class WsRemoteEndpointImplBase
    • getTimeoutExpiry

      protected long getTimeoutExpiry()
    • onTimeout

      protected void onTimeout(boolean useDispatch)
    • setTransformation

      protected void setTransformation(Transformation transformation)
      setTransformation in class WsRemoteEndpointImplBase
    • getLock

      protected Lock getLock()
      Specified by:
      getLock in class WsRemoteEndpointImplBase