conditions references in rules: xml to the rescue?

How to reuse complicated conditions in 
rules?

 

There is a simple way to do it with parsed 
general entities, both internal and external.

As such, parsed general entities allow to reuse any 
part of the rule or policy as long as entity is 

well formed xml.

 

In this case, policy model is not broken and we get 
syntactic shorcut without schema modifications.

 

Here is an example with external parsed general 
entity (internal parsed gen entity is also possible)

 

Suppose we have parsed general entity in 
cond.xml:

<?xml version="1.0" 
encoding="..."?>

<Condition>

    <Apply 
FunctionId="...">

    </Apply>

</Condition>

 

Then in policy.xml:

 

<?xml version="1.0" 
encoding="..."/>

<!DOCTYPE Policy 
[

    
<!ENTITY cond SYSTEM "cond.xml"

]>

<Policy xmlns:xacml="...">

<Rule ...>

    &cond; <-- entity 
reference
</Rule>

</Policy>

 

Simon