Diese Arbeit präsentiert 9 Entwurfsmuster in einer Darstellung durch das Compartment Role Object Model(CROM). Dabei wird dessen graphische Notation für rollenbasierte Modelle mit verschiedenen Möglichkeiten zur Darstellung von Bedingungen des Entwurfsmusters benutzt. Über eine Evaluationsoll ermittelt werden, ob das CROM dazu geeignet ist, die Bedingungen von Entwurfsmustern verständlich und schnell erfassbar darzustellen. Dabei soll die graphische Dokumentation dieser helfen. Das kann positive E ekte auf die Entwicklung von Software haben, wie bessere Codequalität, verkürzte Entwicklungszeiten und die Vereinfachung der Kommunikation zwischen Entwicklern.

Diese Arbeit präsentiert 9 Entwurfsmuster in einer Darstellung durch das Compartment Role Object Model(CROM). Dabei wird dessen graphische Notation für rollenbasierte Modelle mit verschiedenen Möglichkeiten zur Darstellung von Bedingungen des Entwurfsmusters benutzt. Über eine Evaluationsoll ermittelt werden, ob das CROM dazu geeignet ist, die Bedingungen von Entwurfsmustern verständlich und schnell erfassbar darzustellen. Dabei soll die graphische Dokumentation dieser helfen. Das kann positive E ekte auf die Entwicklung von Software haben, wie bessere Codequalität, verkürzte Entwicklungszeiten und die Vereinfachung der Kommunikation zwischen Entwicklern.:1 Einleitung 5 1.1 Motivation 5 1.2 Problemde nition 6 1.3 Zielstellung 6 2 Analyse der betrachteten Darstellungsformen 7 2.1 Beschreibungsform der Gang of Four 7 2.2 Beschreibungsform von Dirk Riehle 10 2.3 Darstellung mit dem Compartment Role Object Model 12 3 Aktualisierung der Entwurfsmuster 17 3.1 Strukturelle Entwurfsmuster 17 3.1.1 Composite Pattern 17 3.1.2 Bridge Pattern 22 3.2 Entwurfsmuster zur Kontextadaption 27 3.2.1 Object Adapter Pattern 27 3.2.2 Class Adapter Pattern 30 3.2.3 Decorator Pattern 33 3.3 Entwurfsmuster zur Zustandsverwaltung 38 3.3.1 State Pattern 38 3.3.2 Property Pattern 43 3.4 Verhaltensorientierte Entwurfsmuster 45 3.4.1 Iterator Pattern 45 3.4.2 Mediator Pattern 50 4 Schlussteil 54 4.1 Abschlieÿender Vergleich 54 4.2 Diskussion 57 4.2.1 Adapter Pattern 57 4.2.2 Klienten 57 4.2.3 Methoden und Attribute 58 4.2.4 Klassen 59 4.3 Zusammenfassung 59 4.3.1 Ergebnis 59 4.3.2 Ausblick 60

Database systems build an integral component of today’s software systems and as such they are the central point for storing and sharing a software system’s data while ensuring global data consistency at the same time. Introducing the primitives of roles and their accompanied metatype distinction in modeling and programming languages, results in a novel paradigm of designing, extending, and programming modern software systems. In detail, roles as modeling concept enable a separation of concerns within an entity. Along with its rigid core, an entity may acquire various roles in different contexts during its lifetime and thus, adapts its behavior and structure dynamically during runtime. Unfortunately, database systems, as important component and global consistency provider of such systems, do not keep pace with this trend. The absence of a metatype distinction, in terms of an entity’s separation of concerns, in the database system results in various problems for the software system in general, for the application developers, and finally for the database system itself. In case of relational database systems, these problems are concentrated under the term role-relational impedance mismatch. In particular, the whole software system is designed by using different semantics on various layers. In case of role-based software systems in combination with relational database systems this gap in semantics between applications and the database system increases dramatically. Consequently, the database system cannot directly represent the richer semantics of roles as well as the accompanied consistency constraints. These constraints have to be ensured by the applications and the database system loses its single point of truth characteristic in the software system. As the applications are in charge of guaranteeing global consistency, their development requires more effort in data management. Moreover, the software system’s data management is distributed over several layers, which results in an unstructured software system architecture. To overcome the role-relational impedance mismatch and bring the database system back in its rightful position as single point of truth in a software system, this thesis introduces the novel and tripartite RSQL approach. It combines a novel database model that represents the metatype distinction as first class citizen in a database system, an adapted query language on the database model’s basis, and finally a proper result representation. Precisely, RSQL’s logical database model introduces Dynamic Data Types, to directly represent the separation of concerns within an entity type on the schema level. On the instance level, the database model defines the notion of a Dynamic Tuple that combines an entity with the notion of roles and thus, allows for dynamic structure adaptations during runtime without changing an entity’s overall type. These definitions build the main data structures on which the database system operates. Moreover, formal operators connecting the query language statements with the database model data structures, complete the database model. The query language, as external database system interface, features an individual data definition, data manipulation, and data query language. Their statements directly represent the metatype distinction to address Dynamic Data Types and Dynamic Tuples, respectively. As a consequence of the novel data structures, the query processing of Dynamic Tuples is completely redesigned. As last piece for a complete database integration of a role-based notion and its accompanied metatype distinction, we specify the RSQL Result Net as result representation. It provides a novel result structure and features functionalities to navigate through query results. Finally, we evaluate all three RSQL components in comparison to a relational database system. This assessment clearly demonstrates the benefits of the roles concept’s full database integration.

Database systems build an integral component of today’s software systems and as such they are the central point for storing and sharing a software system’s data while ensuring global data consistency at the same time. Introducing the primitives of roles and their accompanied metatype distinction in modeling and programming languages, results in a novel paradigm of designing, extending, and programming modern software systems. In detail, roles as modeling concept enable a separation of concerns within an entity. Along with its rigid core, an entity may acquire various roles in different contexts during its lifetime and thus, adapts its behavior and structure dynamically during runtime. Unfortunately, database systems, as important component and global consistency provider of such systems, do not keep pace with this trend. The absence of a metatype distinction, in terms of an entity’s separation of concerns, in the database system results in various problems for the software system in general, for the application developers, and finally for the database system itself. In case of relational database systems, these problems are concentrated under the term role-relational impedance mismatch. In particular, the whole software system is designed by using different semantics on various layers. In case of role-based software systems in combination with relational database systems this gap in semantics between applications and the database system increases dramatically. Consequently, the database system cannot directly represent the richer semantics of roles as well as the accompanied consistency constraints. These constraints have to be ensured by the applications and the database system loses its single point of truth characteristic in the software system. As the applications are in charge of guaranteeing global consistency, their development requires more effort in data management. Moreover, the software system’s data management is distributed over several layers, which results in an unstructured software system architecture. To overcome the role-relational impedance mismatch and bring the database system back in its rightful position as single point of truth in a software system, this thesis introduces the novel and tripartite RSQL approach. It combines a novel database model that represents the metatype distinction as first class citizen in a database system, an adapted query language on the database model’s basis, and finally a proper result representation. Precisely, RSQL’s logical database model introduces Dynamic Data Types, to directly represent the separation of concerns within an entity type on the schema level. On the instance level, the database model defines the notion of a Dynamic Tuple that combines an entity with the notion of roles and thus, allows for dynamic structure adaptations during runtime without changing an entity’s overall type. These definitions build the main data structures on which the database system operates. Moreover, formal operators connecting the query language statements with the database model data structures, complete the database model. The query language, as external database system interface, features an individual data definition, data manipulation, and data query language. Their statements directly represent the metatype distinction to address Dynamic Data Types and Dynamic Tuples, respectively. As a consequence of the novel data structures, the query processing of Dynamic Tuples is completely redesigned. As last piece for a complete database integration of a role-based notion and its accompanied metatype distinction, we specify the RSQL Result Net as result representation. It provides a novel result structure and features functionalities to navigate through query results. Finally, we evaluate all three RSQL components in comparison to a relational database system. This assessment clearly demonstrates the benefits of the roles concept’s full database integration.