Software Quality and Safety Pascal Mbayiha

 software engineering  large, complex systems  functionality, changing requirements  development difficult task  structures, interactions, dependencies...  fighting complexity  principle of separation of concerns separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  general idea  component-based system  consider different views isolated first  local solution, complete system understandable  compose parts  overall system design or implementation separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  component  elemental building block  communication via contracts (interfaces)  behavior-related separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  contract  assumed and guaranteed characteristics  available operations  valid interaction sequences separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha separation of non-orthogonal concerns in software architecture and design  composition of concerns (structural) Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha separation of non-orthogonal concerns in software architecture and design  composition of concerns (behavioural) Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  Floor Plan of an assembly line separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  Production chain view and contract SimpleProcess separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  machine control view and contract Control separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  Monitoring view and contract Monitor separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  composition rules: 1. component in one particular architectural view  sufficient to add it to the composite structure  update dependency relations 2. component in multiple views with distinct contracts  set of contracts is the union of all original  rearrange dependencies if interaction partner has changed separation of non-orthogonal concerns in software architecture and design12 Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  Structural composition Machine separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  easy if contracts are orthogonal  the usage of a contract provided by a given component will never effect clients which uses other contracts of the same component separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  Restriction := ¬([StandBy] ∃ ∧ [Work ∩ Control] ∃ )  for the Control contract – in stand-by, no other contracts should offer substantial work operations separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  Behavior has to be: 1.contract conform  fulfils all contracts 2.restriction conform  no states witch violates restrictions 3.protocol conform  desirable behavior still available  deleted states and transitions  Otherwise:  resolve detected conflict  redesign separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  needed Input:  restrictions and two transition systems  composition of SimpleProcess and Control  restriction:  in Control state Off only provide the transition warmUp within the category Modifier  a machine in state StandBy is designed to allow no activity classified as Work separation of non-orthogonal concerns in software architecture and design R C := ¬ (([Off] ∃ ∧ [Modifier ∩ Control] ∃ ) ∨ ([StandBy] ∃ ∧ [Work ∩ Control] ∃ )) Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha separation of non-orthogonal concerns in software architecture and design Free P rocessing Stand By Off Running register deRegister warmUp start stop shutDown F+O P+O F+S F+R P+S P+R R C := ¬ (([Off] ∃ ∧ [Modifier ∩ Control] ∃ ) ∨ ([StandBy] ∃ ∧ [Work ∩ Control] ∃ )) putPart // compute the complete parallel product S // test all states for compliance with Restrictions // remove s from S if the restrictions are violated // repeat until S has stabilized or Q becomes empty // remove all non protocol-conform (s1, s2) from S Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha separation of non-orthogonal concerns in software architecture and design  redesign Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective R P := ¬ (([Halted] ∃ ∧ [Regular ∩ Process] ∃ ) ∨ ([Processing] ∃ ∧ [Regular ∩ Process] ∃ ))

Pascal Mbayiha separation of non-orthogonal concerns in software architecture and design Free P rocessing Stand By Off Running register deRegister warmUp start stop shutDown H+O H+S F+O P+O F+S F+R R P := ¬ (([Halted] ∃ ∧ [Regular ∩ Process] ∃ ) ∨ ([Processing] ∃ ∧ [Regular ∩ Process] ∃ )) putPart Halted Stopped H+R S+O S+S P+S P+R S+R deRegister // compute the complete parallel product S // test all states for compliance with both Restrictions // remove s from S if the restrictions are violated // repeat until S has stabilized or Q becomes empty // remove all non protocol-conform (s1, s2) from S R C := ¬ (([Off] ∃ ∧ [Modifier ∩ Control] ∃ ) ∨ ([StandBy] ∃ ∧ [Work ∩ Control] ∃ )) Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  check state by state  combine multiple contracts simultaneous  symbolic representation of labeled transitions  efficient encoding of state space, transitions  efficient reachability analysis with symbolic techniques  handle more complex composition problems with multiple, moderately large architectural views separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha  specification without real-time  in reality real-time behavior  every thing need time  expand the approach separation of non-orthogonal concerns in software architecture and design Introduction | basic concepts | structural composition | behavioral composition | synthesis algorithm | perspective

Pascal Mbayiha separation of non-orthogonal concerns in software architecture and design23

Pascal Mbayiha  A Methodology for Specifying and Analyzing Consistency of Object-Oriented Behavioral Models  consistency for each protocol and components  specify all statecharts completely before a consistency check  Presented approach:  the connection between components to be consistent  test all protocols and additional restrictions separation of non-orthogonal concerns in software architecture and design

Pascal Mbayiha  a set offers(s) := {a ∈ A|∃s’ ∈ S : s[a>s} denotes the labels of all available steps from a given state s.  For a general composition of multiple contracts, it is required to respect the two different forms of contract transitions.  The regular behavior of one contract, as specified by its labelled transitions, has to be combined with the reflexive and transitive closure of the τ steps of the other ones separation of non-orthogonal concerns in software architecture and design

Pascal Mbayiha  Symbolic encoding separation of non-orthogonal concerns in software architecture and design