4. The method of claim 1 , wherein the complex policies data structure is filtered by a compressed Deterministic Finite Automaton (DFA) structure for representing the query, and a stack structure for representing currently active tags of the XML document, the stack structure being used for traversing the DFA structure on receipt of a tag in the document that matches a final location step of the query.
4. The method of claim 1 , wherein the complex policies data structure is filtered by a compressed Deterministic Finite Automaton (DFA) structure for representing the query, and a stack structure for representing currently active tags of the XML document, the stack structure being used for traversing the DFA structure on receipt of a tag in the document that matches a final location step of the query. 5. The method of claim 4 , wherein the stack structure uses a single stack for all tags received from the document and a second stack for the wildcard “*”.