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  1. OMG Issue

DDS11 — DDS ISSUE# 50] Multiple observers sharing a datareader

  • Key: DDS11-8
  • Legacy Issue Number: 6850
  • Status: open  
  • Source: Real-Time Innovations ( Dr. Gerardo Pardo-Castellote, Ph.D.)
  • Summary:

    Ref-166 Allow_multiple_observers_on_a_datareader

    Currently there can only be one "observer" on each DataReader. In
    other words, it is not possible to have some independent application
    observe the data that a DataReader gets without at the same time
    affecting the sample-state and this the behavior of other

    It is often the case that debugging tool, an interceptor or some other
    utility would like to access the data available on the DataReader
    without making its presence noted and thus changing the behavior of
    other readers. This is particularly relevant for the built-in topics.


    Add an operation: DataReader:: create_view that returns a
    DataReader. This affects and the IDL in 2.2.3

    This DataReader is a view on the same DataReader so it has the same
    QoS and listeners.

    The application can use the original DataReader or a view to perform
    any operations allowed on a DataReader.

    A change of QoS or listener in one view or on the main object affects
    the main object and all views.

    Read and Take operations act independently on each view. The
    application must take the data from all views before it can be removed
    from the infrastructure and the resources reclaimed.

  • Reported: DDS 1.0b1 — Tue, 23 Dec 2003 05:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT