Class InboundConnectionCacheImpl<C extends Connection>

All Implemented Interfaces:
ConnectionCache<C>, InboundConnectionCache<C>

public final class InboundConnectionCacheImpl<C extends Connection> extends ConnectionCacheNonBlockingBase<C> implements InboundConnectionCache<C>
Manage connections that are initiated from another VM. Connections are reclaimed when they are no longer in use and there are too many connections open.

A connection basically represents some sort of communication channel, but few requirements are placed on the connection. Basically the ability to close a connection is required in order for reclamation to work.

  • Field Details

  • Constructor Details

    • InboundConnectionCacheImpl

      public InboundConnectionCacheImpl(String cacheType, int highWaterMark, int numberToReclaim, long ttl)
  • Method Details

    • thisClassName

      protected String thisClassName()
      Specified by:
      thisClassName in class ConnectionCacheBase<C extends Connection>
    • requestReceived

      public void requestReceived(C conn)
      Description copied from interface: InboundConnectionCache
      Mark a connection as busy because a request is being processed on the connection. The connection may or may not be previously known to the cache when this method is called. Busy connections cannot be reclaimed. This provides an early indication that a Connection is in use, before we know how many responses still need to be sent on the Connection for this request. This reduces the likelyhood of reclaiming a connection on which we are processing a request.

      Note that this problem is inherent in a distributed system. We could in any case reclaim a connection AFTER a client has sent a request but BEFORE the request is received. Note that AFTER and BEFORE refer to global time which does not really exist in a distributed system (or at least we want to pretend it is not available). XXX Should we age out connections? This would require actual time stamps, rather than just an LRU queue.

      Specified by:
      requestReceived in interface InboundConnectionCache<C extends Connection>
      Parameters:
      conn - connection to mark as busy
    • msg

      @InfoMethod private void msg(String m)
    • display

      @InfoMethod private void display(String m, Object value)
    • requestProcessed

      public void requestProcessed(C conn, int numResponsesExpected)
      Description copied from interface: InboundConnectionCache
      Indicate that request processing has been completed for a request received on conn. This indicates that a Connection that received a request as indicated in a previous call to requestReceived has completed request processing for that request. Responses may still need to be sent. Some number of responses (usually 0 or 1) may be expected ON THE SAME CONNECTION even for an idle connection. We maintain a count of the number of outstanding responses we expect for protocols that return the response on the same connection on which the request was received. This is necessary to prevent reclamation of a Connection that is idle, but still needed to send responses to old requests.
      Specified by:
      requestProcessed in interface InboundConnectionCache<C extends Connection>
      Parameters:
      conn - connection to mark as completed
      numResponsesExpected - responses expected
    • responseSent

      public void responseSent(C conn)
      Decrement the number of expected responses. When a connection is idle and has no expected responses, it can be reclaimed.
      Specified by:
      responseSent in interface InboundConnectionCache<C extends Connection>
      Parameters:
      conn - connection that response has been sent on
    • close

      public void close(C conn)
      Close a connection, regardless of whether the connection is busy or not.
      Specified by:
      close in interface ConnectionCache<C extends Connection>
      Parameters:
      conn - connection to close
    • getConnectionState

      private InboundConnectionCacheImpl.ConnectionState<C> getConnectionState(C conn)