Mo 2
       January 21-25, 2008, Munich, Germany 
       ICM - International Congress Centre Munich 
        
       Pattern-Oriented Software Architecture 
        
       Frank Buschmann 
       Kevlin Henney 
        
        
        
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                                                         T                        Pattern-Oriented 
                                                        R C H I
                                                         
                                                        A                         Software Architecture
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                                                                                    Kevlin Henney                                             Frank Buschmann
                                                                                    Kevlin Henney                                             Frank Buschmann
                                                                                                  Curbralan Limited                                                                   Siemens AG
                                                                                                  Curbralan Limited                                                                   Siemens AG
                                                                                         kevlin@curbralan.com                                  frank.buschmann@siemens.com
                                                                                          kevlin@curbralan.com                                 frank.buschmann@siemens.com
                                                         E
                                                                             Agenda
                                                         C H I T E C T U R 
                                                          R                              ƒ     Introduction
                                                          R E    A
                                                         W A                             ƒ     Stand-Alone Patterns
                                                          E D   S O F T                  ƒ     Pattern Complements / Pattern Compounds
                                                          R I E N T                      ƒ     Pattern Stories / Pattern Sequences
                                                         O
                                                                                         ƒ     Pattern Languages
                                                          T T T E R N –                  ƒ     Outroduction
                                                         P A
                                                                                         ƒ     References
                                                                             Pattern-Oriented Software Architecture                         2          ©Frank Buschmann, Kevlin Henney, all rights reserved
                                                                                                                                                                                                                                                          1
                                                         E
                                                                             Where we are
                                                         C H I T E C T U R 
                                                          R                              ƒ     Introduction
                                                          R E    A
                                                         W A                             ƒ     Stand-Alone Patterns
                                                          E D   S O F T                  ƒ     Pattern Complements / Pattern Compounds
                                                          R I E N T                      ƒ     Pattern Stories / Pattern Sequences
                                                         O
                                                                                         ƒ     Pattern Languages
                                                          T T T E R N –                  ƒ     Outroduction
                                                         P A
                                                                                         ƒ     References
                                                                             Pattern-Oriented Software Architecture                         3          ©Frank Buschmann, Kevlin Henney, all rights reserved
                                                         E
                                                                             On Designing with Patterns (1)
                                                         C H I T E C T U R 
                                                          R                  Patterns have become a popular tool in software design …
                                                          R E    A           • They have changed the way software developers
                                                         W A                    think about and practice software design
                                                          E D   S O F T      • They provide us with a software design vocabulary
                                                                             • They help us to resolve recurring problems
                                                          R I E N T             constructively and based on proven solutions
                                                         O                   • They support us in understanding the architecture
                                                                                of a given software system
                                                          T T T E R N –      • ...
                                                         P A
                                                                             But: applying patterns in software design is not necessarily 
                                                                                designing with patterns!
                                                                             Pattern-Oriented Software Architecture                         4          ©Frank Buschmann, Kevlin Henney, all rights reserved
                                                                                                                                                                                                                                                          2
                                                  E
                                                                   On Designing with Patterns (2)
                                                  C H I T E C T U R 
                                                   R               Patterns applied in isolation and as modular building blocks do 
                                                   R E    A           not create sustainable designs.                                                        Command
                                                  W A                                                                                                        Processor
                                                                   Solutions
                                                                                                                                 Client      Command         Logging       Logging
                                                   E D   S O F T   • Fail to consider the surrounding                                        Processor       Context       Strategy
                                                                      problems and their solutions.
                                                                                                                                             Component   *                 Concrete
                                                                   • Have at best only local effects.                                                                       Logging
                                                   R I E N T                                                                                                                Strategy
                                                  O
                                                                   • Do not complement one another                        Composite                                        Strategy
                                                                                                                                          Leaf      Composite
                                                                      or mutually reinforce their                                                          n
                                                                                                                                                        ig
                                                                                                                                                       s
                                                                                                                                                     e
                                                   T T T E R N –      beneficial properties.                                                   or D
                                                  P A                                                                                       Po                          Memento
                                                                   • Create complex architectures                                       Command             Caretaker
                                                                      that lack useful operational and
                                                                      developmental qualities.                                   Concrete      Concrete
                                                                                                                                Command       Command       Memento
                                                                                                                         Command
                                                                                                                                            Application
                                                                   Pattern-Oriented Software Architecture                 5         ©Frank Buschmann, Kevlin Henney, all rights reserved
                                                  E
                                                                   On Designing with Patterns (3)
                                                  C H I T E C T U R 
                                                   R               There are two fundamental ways of integrating patterns:
                                                   R E    A        • Refinement: One pattern refines the structure and behavior of another 
                                                  W A                 pattern to address a specific sub-problem or implementation detail.
                                                   E D   S O F T   • Combination: Two or more patterns arranged to form a larger structure 
                                                                      that addresses a more complex problem.
                                                   R I E N T
                                                  O                There are also relationships regarding choice:
                                                   T T T E R N –   • Alternatives: Some patterns describe alternatives to one another. They 
                                                  P A                 address the same or a similar problem, but each pattern considers a slightly 
                                                                      different set of forces. Thus, the patterns provide different solutions and have 
                                                                      different consequences.
                                                                   • Cooperation: Some patterns nicely complement one another, mutually 
                                                                      reinforcing their structural and behavioral properties.
                                                                   Pattern-Oriented Software Architecture                 6         ©Frank Buschmann, Kevlin Henney, all rights reserved
                                                                                                                                                                                                                           3