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[CDO] View update timing/concurrency [message #1790463]

Mon, 11 June 2018 12:14

Robert Schulk

Messages: 144
Registered: July 2015

Senior Member

I was wondering what happens in this case:

* A class has two containment references x and y
* An object of this class is viewed by one client with a CDOView
* The object's references are both modified from another client by a CDOTransaction and a single commit.

Now let's say the viewing client exports the object to XML exactly during the update. Would it be possible that the exported file contains the changes for reference "x" but not for reference "y"?

Also, am I correct to assume that this is definitely prevented by using CDOView#syncExec?

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Re: [CDO] View update timing/concurrency [message #1790474 is a reply to message #1790463]

Mon, 11 June 2018 13:26

Eike Stepper

Messages: 6682
Registered: July 2009

Senior Member

Remote updates are incorporated into a local model by the invalidator thread of the view like so:

    synchronized (getViewMonitor())
    {
      lockView();

      try
      {
        doInvalidateSynced(invalidationData);
      }
      finally
      {
        unlockView();
      }
    }

If you don't want your model access be interrupted by the invalidator thread you should use CDOView.syncExec, which is implemented as follows:

  public void syncExec(Runnable runnable)
  {
    synchronized (getViewMonitor())
    {
      lockView();

      try
      {
        runnable.run();
      }
      finally
      {
        unlockView();
      }
    }
  }

Cheers
/Eike

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