Model Driven Development (MDD) is considered as a powerful emerging paradigm for developing system software and services. MDD relies heavily on the models to generate part of the code for implementation. It is virtually inevitable that changes at the model level result in breaking the compatibility with the existing code base. The study presented in this thesis is performed in an industrial setting. Our industrial partner is involved in MDD and has experienced compatibility problems described above. The aim of this thesis is to identify the changes that can be made to UML class diagram and investigate what kind of negative impact they pose on the compatibility with already existing Java implementations. Apart from identifying possible model changes and assessing their negative impact the thesis provides suggestions and guidelines of how to perform such modifications so that their negative impact will be minimized. / +46 455-395070

A state machine model can turn a complex behavioural system into a more accessible graphical model, and can improve the way people work with system design by making it easier to communicate and understand the system. The clear structure of a state machine model enables automatic generation of well structured, and consequently readable, and maintainable code. There are many known implementations and even plenty of commercial software available for working with state machines, and the goal of this project is to compare and discuss some of these implementations in the context of Ericsson's demands for run time, memory usage, scalability, readability, and maintainability. More specifically, the project focuses on the state machine models specified in the UML (the unified modeling language [15]), utilizing UML's associated markup language, XMI, to go from graphical model to generated C code. The resulting C code is primarily a code skeleton which only provides the basic behaviour of transitioning between states given a specific event, it is expected that the developers manually implement additional features themselves. The examined implementations are: Nested Switch, Array of Structs, Function Pointers, Basic State Pattern, State-Table Pattern, and Hierarchical State Pattern. Additionally, the project investigates how multiple state machines can communicate and work together as interacting state machines. And finally, to showcase how a state machine implementation can be maintainable, we develop an iterative code editor that can edit already operating and manually modified state machine implementations. The implementations are tested on a case study example provided by Ericsson, aimed to represent a sort of typical state machine design when it comes to number of states and events. The implementations are further tested with randomly generated state machines, to examine their scalability properties. In our opinion the results favour the Array of Structs and Basic State Pattern implementations and the choice depends on the optimisation used and the priority between run time and memory.

<p>Општи информациони модел (CIM) користи се за опис електроенергетске мреже и за размену података између оператера преносних електроенергетских система. Како је модел постајао све заступљенији, појавила се потреба за његовим складиштењем. У раду је развијен методолошки приступ за развој базе података која би подржала релативно једноставно складиштење и рад са инстанцама CIM модела, које описују тренутно, активно стање у систему. Такође, омогућено је и праћење претходних, историјских стања CIM инстанци, као и њихова рестаурација у жељено стање. Очекује се да предложени приступ олакша увођење CIM модела у различита, наменска програмска решења.</p> / <p>Opšti informacioni model (CIM) koristi se za opis elektroenergetske mreže i za razmenu podataka između operatera prenosnih elektroenergetskih sistema. Kako je model postajao sve zastupljeniji, pojavila se potreba za njegovim skladištenjem. U radu je razvijen metodološki pristup za razvoj baze podataka koja bi podržala relativno jednostavno skladištenje i rad sa instancama CIM modela, koje opisuju trenutno, aktivno stanje u sistemu. Takođe, omogućeno je i praćenje prethodnih, istorijskih stanja CIM instanci, kao i njihova restauracija u željeno stanje. Očekuje se da predloženi pristup olakša uvođenje CIM modela u različita, namenska programska rešenja.</p> / <p>Common Information Model (CIM) is used for describing power grid networks<br />and data exchange among transmission system operators (TSO). As the<br />model became widely used, there was a need to store such model. In this<br />thesis we present a methodological approach to development of a database<br />that supports relatively easy storing and managing CIM instances, which<br />describe current, active state of the system. Also, tracking changes and<br />restoring CIM instances to its previous states are supported. We expect that<br />such methodological approach would ease the implementation of CIM model<br />in various, domain specific software solutions.</p>