[storm] Before commit checking

[Gerdus van Zyl]

Hi

Is there a way to run a validation function before committing in
storm? I tried to implement it by sub classing Store but could not
figure out how to get a list of objects that will be affected by the
commit. The use I have is I have a main GlTrans object with GlEntries
and the GlEntries debits and credits should balance.

Thank you
Gerdus