[dtp-dev] syncExec or asyncExec when refreshing?

[Hui.Cao@xxxxxxxxxx]

Hi,
        I
have a question about ServerExplorerContentProviderNav.notifyChanged.
Currently it's using syncExec to refresh DSE. Are there any specific reasons
to do so? Is it possible to use asynExec?

    public void notifyChanged(final
ICatalogObject dmElement, int eventType) {
        if (eventType
== ICatalogObjectListener.EventTypeEnumeration.ELEMENT_REFRESH &&
viewer != null)
        {
           
viewer.getControl().getDisplay().syncExec(new Runnable() {
           
    public void run() {
           
        viewer.refresh(dmElement, true);
           
    }
           
});
        }
        }

        I
ask this question because I encountered a UI thread contention problem
in one of our enablement project (ASE). The symptom is: in DSE, expand
the columns node, refresh the table node, then expand the table again,
Eclipse UI is freezed. I can't reproduce this problem for Derby, and I
found out the difference is in the way the content provider is written,
which results in Derby constraints are loaded during refresh, while ASE
constraints are not. Then, when I expand the table node again, deadlock
occurs. If I change the above code from syncExec to asyncExec, the problem
is solved. Of course, I can also change ASE content provider in the same
ways as Derby content provider, but I feel async refresh would be more
safe.

        Thanks
in advance!

Best Regards!

Max (Hui) Cao
Sybase Shanghai RD