Package org.jgroups.blocks

Class MultiRequest

java.lang.Object
org.jgroups.blocks.Request
org.jgroups.blocks.MultiRequest
All Implemented Interfaces:
Future, RspCollector, Command, NotifyingFuture
public class MultiRequest extends Request
Sends a request to multiple destinations. Alternative implementation when we have few targets: between UnicastRequest with 1 target and GroupRequest with many destination members. Performance is about the same as for GroupRequest, but this class should use less memory as it doesn't create hashmaps. Don't use with many targets as we have to do a linear search through an array of targets to match a response to a request.

MultiRequest is currently not used

Since:
2.9
Author:
Bela Ban

  • Field Details

    • expected_mbrs

      protected final int expected_mbrs

  • Constructor Details

    • MultiRequest

      public MultiRequest(Message m, RequestCorrelator corr, Collection<Address> mbrs, RequestOptions options, int expected_mbrs)
      Parameters:
      m - The message to be sent
      corr - The request correlator to be used. A request correlator sends requests tagged with a unique ID and notifies the sender when matching responses are received. The reason GroupRequest uses it instead of a Transport is that multiple requests/responses might be sent/received concurrently.
      mbrs - The initial membership. This value reflects the membership to which the request is sent (and from which potential responses are expected). Is reset by reset().
      options - The options to be passed to the request

    • MultiRequest

      public MultiRequest(Message m, RequestCorrelator corr, Address target, RequestOptions options, int expected_mbrs)

    • MultiRequest

      public MultiRequest(Message m, Transport transport, Collection<Address> mbrs, RequestOptions options, int expected_mbrs)
      Parameters:
      timeout - Time to wait for responses (ms). A value of invalid input: '<'= 0 means wait indefinitely (e.g. if a suspicion service is available; timeouts are not needed).

  • Method Details

    • getAnycasting

      public boolean getAnycasting()

    • setAnycasting

      public void setAnycasting(boolean anycasting)

    • sendRequest

      public void sendRequest() throws Exception
      Specified by:
      sendRequest in class Request
      Throws:
      Exception

    • receiveResponse

      public void receiveResponse(Object response_value, Address sender)
      Callback (called by RequestCorrelator or Transport). Adds a response to the response table. When all responses have been received, execute() returns.
      Specified by:
      receiveResponse in interface RspCollector
      Specified by:
      receiveResponse in class Request

    • suspect

      public void suspect(Address suspected_member)
      Callback (called by RequestCorrelator or Transport). Report to GroupRequest that a member is reported as faulty (suspected). This method would probably be called when getting a suspect message from a failure detector (where available). It is used to exclude faulty members from the response list.
      Specified by:
      suspect in interface RspCollector
      Specified by:
      suspect in class Request

    • viewChange

      public void viewChange(View new_view)
      Any member of 'membership' that is not in the new view is flagged as SUSPECTED. Any member in the new view that is not in the membership (ie, the set of responses expected for the current RPC) will not be added to it. If we did this we might run into the following problem:
      • Membership is {A,B}
      • A sends a synchronous group RPC (which sleeps for 60 secs in the invocation handler)
      • C joins while A waits for responses from A and B
      • If this would generate a new view {A,B,C} and if this expanded the response set to {A,B,C}, A would wait forever on C's response because C never received the request in the first place, therefore won't send a response.
      Specified by:
      viewChange in interface RspCollector
      Specified by:
      viewChange in class Request

    • getResults

      public RspList getResults()
      Returns the results as a RspList

    • get

      public RspList get() throws InterruptedException, ExecutionException
      Throws:
      InterruptedException
      ExecutionException

    • get

      public RspList get(long timeout, TimeUnit unit) throws InterruptedException, ExecutionException, TimeoutException
      Throws:
      InterruptedException
      ExecutionException
      TimeoutException

    • toString

      public String toString()
      Overrides:
      toString in class Request

    • responsesComplete

      protected boolean responsesComplete()
      Specified by:
      responsesComplete in class Request