I think I know how to manage transactions in Zope, but I don't know how to lock Zope resources for multiple requests.

For example :

I have a DTML Method, called "transac1", which looks like this :

<dtml-if "var==0">
<dtml-call wait_10_seconds>
"waiting 10 seconds..."
<dtml-call "manage_editProperties({'var':1})">
</dtml-if>

wait_10_seconds is an External Method that sleeps for 10 seconds.

In the other hand, I have another method, called "transac2" :

<dtml-if "var==0">
<dtml-call "manage_editProperties({'var':2})">
<dtml-else>
<dtml-call "manage_editProperties({'var':3})">
</dtml-if>

In the parent Folder, there's a property called "var" which I use in these methods. It has an initial value of 0.

The point is : if I call the first method, and while it's sleeping, I call the second one (from another window, for example), it doesn't work properly. The first one crashes, and doesn't finish right. The final "var" value is 2.

I want to know if there is any way to lock the folder, and its properties, so no one can access to it until my method "transac1" finishes, and where can I find information about locking resources in Zope.