| Author: | Tuomas J. Lukka |
|---|---|
| Last-Modified: | 2003-08-17 |
| Revision: | 1.3 |
| Status: | Accepted |
The NodeFunction framework is misused in several places in Fenfire, as there are lots of node functions for which the invariants do not hold.
This PEG suggests a way forwards to both not require too great changes to current code but allow pure functional semantics to be specified and applied.
Change NodeFunction spec to not specify any invariants for it.
Add a new interface, PureNodeFunction as a subinterface of NodeFunction.
It defines no methods but explicitly defines the invariant.
CachedNodeFunction shall only accept PureNodeFunctions.
PureNodeFunction-implementing classes SHALL BE IMMUTABLE - all members will be final. Changing members will work by creating a new instance with a changed member.