Formal Modeling of Feature Interaction in Product Line

1. Formal Modeling of Feature Interaction in Product Line November 2005 Yuji ARICHIKA,Keijiro ARAKI Kyushu University {arichika,araki}@ale.csce.kyushu-u.ac.jp 1

2. Background Product line software engineering • Software development frame work to develop reusable assets and develop each products by using reusable assets FORM (Feature Oriented Reuse Method) • Feature oriented PLSE methods • We analyze feature by using feature model • We can’t analyze feature interaction strictly because feature model has ambiguity Feature interaction • Selected features interact each other and whole of the system can't perform well It is important to describe formal model of feature and feature interaction 2

3. Classification of Feature Interaction • Parallel feature: feature interactions which can arise when two features operate in the same time（feature A, B） • Sequential feature interaction: feature interactions which can arise when two features operate sequentially • Direct sequential feature interaction （feature A, C) • Indirect sequential feature interaction（feature A, D） time feature A feature B feature C feature D 3

4. Example of Parallel Feature Interaction Telecommunication system • Call Forwarding Feature：forwarding calls to registered telephone • Originating Call Screening： restricting calls to telephone that appear on a screening list • Feature interaction：two features has same registered telephones call Telephone C Telephone A Telephone B Originating Call Screening Feature ：Telephone C Call Forwarding Feature：Telephone C 4

5. Feature A +Feature B Pre or Post => and => Feature A Pre Post Feature B Pre Post conditionA1 conditionB1 conditionB1 conditionA1 conditionA1 conditionA2 conditionA2 conditionB2 conditionB1 conditionB2 Formal Modeling of Feature Interaction Formal modeling of feature • Describe features as a function • Describe conditions to operate the feature in pre condition of the function • Describe conditions which the system have to fulfill when the feature is operated in post condition of the function Formal modeling of feature interaction • Describe as a function expressionlike a schema expression of Z 5

6. o_screening pre caller in set dom telephone_system.terminating _call_screening and callee in set telephone_system.terminating_call_screening(caller) post mk_(caller,callee) not in set out_telephone_system.basic_calling; s_callup（o_forwarding + o_screening） pre pre_o_forwarding(telephone_system, caller, callee) or pre_o_screening(telephone_system, caller, callee) post (pre_o_forwarding(telephone_system, caller, callee) =>post_o_forwarding(telephone_system, caller, callee, out_telephone_system)) and (pre_o_screening(telephone_system, caller, callee) => post_o_screening(telephone_system, caller, callee, out_telephone_system)); Formal Model of Feature Interaction o_forwarding pre telephone_system.call_forwarding(caller) <> nil post mk_(caller, telephone_system.call_forwarding(callee)) in set out_telephone_system.basic_calling; feature interaction not forall s1 in set setTS, caller in set setTel, callee in set setTel & pre_s_callup(s1, caller, callee) => exists s2 in set setTS & post_s_callup(s1, caller, callee, s2) 6