Topic Area Architecture & Design: Content Content • Proto-OCL • Introduction and Vocabulary VL 10 • syntax, semantics, • Software Modelling I Softwaretechnik / Software-Engineering • Proto-OCL vs. OCL. . . (i) views and viewpoints, the 4+1 view . • Proto-OCL vs. Software (ii) model-driven/-based software engineering • An outlook on UML Lecture 12: Proto-OCL, (iii) Modelling structure VL 11 . a) (simplified) class diagrams . • Principles of (Good) Design . b) (simplified) object diagrams Modularisation & Design Patterns VL 12 c) (simplified) object constraint logic (OCL) • modularity, separation of concerns d) Unified Modelling Language (UML) • information hiding and data encapsulation • abstract data types, object orientation • Principles of Design 2017-07-03 • ...by example . (i) modularity, separation of concerns . . (ii) information hiding and data encapsulation • Architecture Patterns (iii) abstract data types, object orientation (iv) Design Patterns • Layered Architectures, Pipe-Filter, Prof. Dr. Andreas Podelski, Dr. Bernd Westphal Model-View-Controller. VL 13 • Software Modelling II – 12 – 2017-07-03 – Sblockcontent – • Design Patterns . – 12 – 2017-07-03 – Scontent – Albert-Ludwigs-Universität Freiburg, Germany (i) Modelling behaviour . – 12 – 2017-07-03 – main – . a) communicating finite automata • Strategy, Examples b) Uppaal query language VL 14 c) basic state-machines • Libraries and Frameworks . . . d) an outlook on hierarchical state-machines 2 /66 3 /66 Content Partial vs. Complete Object Diagrams Special Case: Anonymous Objects • Proto-OCL • syntax, semantics, If the object diagram • By now we discussed “ object diagram represents system state ”: • Proto-OCL vs. OCL. • Proto-OCL vs. Software { 1 C 7 � { p 7 � � , n 7 � { 5 C }} , : C 5 C : C p n p 1 C : C n 1 D : D 1 C : C : D 5 C 7 � { p 7 � � , n 7 � � } , � p = � p = � p = � x = 23 p = � x = 23 1 D 7 � { p 7 � { 5 C } , x 7 � 23 }} n = � n = � • An outlook on UML What about the other way round...? is considered as complete , then it denotes the set of all system states • Principles of (Good) Design • Object diagrams can be partial , e.g. { 1 C 7 � { p 7 � � , n 7 � { c }}} , c 7 � { p 7 � � , n 7 � � } , d 7 � { p 7 � { c } , x 7 � 23 }} • modularity, separation of concerns 1 C : C n 5 C : C 1 D : D • information hiding and data encapsulation or 1 C : C 5 C : C 1 D : D where c � D ( C ) , d � D ( D ) , c 6 = 1 C . x = 23 • abstract data types, object orientation � we may omit information. Intuition : different boxes represent different objects. • ...by example • Is the following object diagram partial or complete ? • Architecture Patterns 5 C : C p • Layered Architectures, Pipe-Filter, 1 C : C n 1 D : D p = � p = � x = 23 n = � Model-View-Controller. • If an object diagram – 12 – 2017-07-03 – Scontent – • Design Patterns – 11 – 2017-06-26 – Sod – – 11 – 2017-06-26 – Sod – – 12 – 2017-07-03 – main – • has values for all attributes of all objects in the diagram, and – 12 – 2017-07-03 – main – • Strategy, Examples • if we say that it is meant to be complete then we can uniquely reconstruct a system state � . 39 /51 40 /51 • Libraries and Frameworks 4 /66 5 /66 6 /66
Motivation Constraints on System States C C x : Int c 0,1 • Example : for all C -instances, x should never have the value 27 . a D A 0,1 ∀ c ∈ allInstances C • x ( c ) � = 27 Towards Object Constraint Logic (OCL) • Proto-OCL Syntax wrt. signature ( T , C , V, atr , F, mth ) , c is a logical variable , C ∈ C : — “Proto-OCL” — • How do I precisely, formally tell my developers that F ::= : τ C c All D -instances having a link to the same C object | allInstances C : 2 τ C should have links to the same A . | v ( F ) : τ C → τ ⊥ , if v : τ ∈ atr ( C ) • That is, the following system state is forbidden in the software: | v ( F ) : τ C → τ D , if v : D 0 , 1 ∈ atr ( C ) | : τ C → 2 τ D , if v : D ∗ ∈ atr ( C ) v ( F ) : A a : D c : C c : D a : A | f ( F 1 , . . . , F n ) : τ 1 × · · · × τ n → τ, if f : τ 1 × · · · × τ n → τ : τ C × 2 τ C × B ⊥ → B ⊥ | ∀ c ∈ F 1 • F 2 Note: formally, it is a proper system state . – 12 – 2017-07-03 – main – – 12 – 2017-07-03 – Socl – – 12 – 2017-07-03 – Socl – • Use (Proto-)OCL : “Dear developers, please only use system states which satisfy:” • The formula above in prefix normal form : ∀ c ∈ allInstances C • � = ( x ( c ) , 27) ∀ d 1 ∈ allInstances C • ∀ d 2 ∈ allInstances C • c ( d 1 ) = c ( d 2 ) = ⇒ a ( d 1 ) = a ( d 2 ) 7 /66 8 /66 9 /66 Semantics Semantics Cont’d Example: Evaluate Formula for System State • Proto-OCL Types: C • Proto-OCL is a three-valued logic: a formula evaluates to true , false , or ⊥ . 1 C : C σ : x : Int • I � τ C � = D ( C ) ˙ I � τ ⊥ � = D ( τ ) ˙ I � 2 τ C � = D ( C ∗ ) ˙ ∪ {⊥} , ∪ {⊥} , ∪ {⊥} x = 13 • Example : ∧ I ( · , · ) : { true , false , ⊥} × { true , false , ⊥} → { true , false , ⊥} is defined as follows: • I � B ⊥ � = { true , false } ˙ ∪ {⊥} , I � Z ⊥ � = Z ˙ ∪ {⊥} ∀ c ∈ allInstances C • x ( c ) � = 27 • Functions: x 1 true true true false false false ⊥ ⊥ ⊥ x 2 true false ⊥ true false ⊥ true false ⊥ • We assume f I given for each function symbol f ( → in a minute). • Recall prefix notation : ∀ c ∈ allInstances C • � =( x ( c ) , 27) ∧ I ( x 1 , x 2 ) true false ⊥ false false false ⊥ false ⊥ Note : � = is a binary function symbol, 27 is a 0 -ary function symbol. • Proto-OCL Semantics (interpretation function): We assume common logical connectives ¬ , ∧ , ∨ , . . . with canonical 3-valued interpretation. • Example : • I � c � ( σ, β ) = β ( c ) (assuming β is a type-consistent valuation of the logical variables), • Example : + I ( · , · ) : ( Z ˙ ∪ {⊥} ) × ( Z ˙ ∪ {⊥} ) → Z ˙ ∪ {⊥} I � ∀ c ∈ allInstances C • � =( x ( c ) , 27) � ( σ, ∅ ) = true , because... • I � allInstances C � ( σ, β ) = dom( σ ) ∩ D ( C ) , � x 1 + x 2 , if x 1 � = ⊥ and x 2 � = ⊥ I � � =( x ( c ) , 27) � ( σ, β ) , β := ∅ [ c := 1 C ] = { c �→ 1 C } � σ ( I � F � ( σ, β )) ( v ) , if I � F � ( σ, β ) ∈ dom( σ ) + I ( x 1 , x 2 ) = ⊥ , otherwise • I � v ( F ) � ( σ, β ) = (if not v : C 0 , 1 ) ⊥ , otherwise = � = I ( I � x ( c ) � ( σ, β ) , I � 27 � ( σ, β ) ) We assume common arithmetic operations − , /, ∗ , . . . � σ ( u ′ )( v ) , if I � F � ( σ, β ) = { u ′ } ⊆ dom( σ ) and relation symbols >, <, ≤ , . . . with monotone 3-valued interpretation. = � = I ( σ ( I � c � ( σ, β ) )( x ) , 27 I ) • I � v ( F ) � ( σ, β ) = (if v : C 0 , 1 ) ⊥ , otherwise • And we assume the special unary function symbol isUndefined : = � = I ( σ ( β ( c ) )( x ) , 27 I ) • I � f ( F 1 , . . . , F n ) � ( σ, β ) = f I ( I � F 1 � ( σ, β ) , . . . , I � F n � ( σ, β )) , – 12 – 2017-07-03 – Socl – – 12 – 2017-07-03 – Socl – – 12 – 2017-07-03 – Socl – = � = I ( σ ( 1 C )( x ) , 27 I ) � true , if x = ⊥ , true , if I � F 2 � ( σ, β [ c := u ]) = true for all u ∈ I � F 1 � ( σ, β ) isUndefined I ( x ) = false , otherwise = � = I ( 13 , 27 ) = true ...and 1 C is the only C -object in σ : I � allInstances C � ( σ, ∅ ) = { 1 C } . • I � ∀ c ∈ F 1 • F 2 � ( σ, β ) = false , if I � F 2 � ( σ, β [ c := u ]) = false for some u ∈ I � F 1 � ( σ, β ) ⊥ , otherwise isUndefined I is definite : it never yields ⊥ . 10 /66 11 /66 12 /66
Recommend
More recommend
