Cancellation of modifications in Epic

Hello! I use Epic Editor 5.1. I've read that it was impossible to cancel xml modification in event handlers.

In Java plugin I use calls like this in DOMSubtreeModifiedListener_ when we deal with node removing:

((ADocument) doc).undo();

But when I deal with node insertion, I get the following error in DOMSubtreeModifiedListener_ :

epic: segment violation (signal 11)

undo procedure for insertion is made within DOMNodeInsertedListener_ and DOMSubtreeModifiedListener_ does not execute undo procedure for insertion (the situation is inverse for removing - undo is called within DOMSubtreeModifiedListener_).

What are the tricks for indirect cancellation?

If I should use ACL, then show me the example of it for Java using Acl class, please.

I mean the link of handler written in ACL and the ACL event by Java means.

I'd like to avoid using external additional *.acl files in my Java plugin, instead of it I'd like to store acl scripts in String objects.