Generating UML diagrams from LEM

Transcription

1 Generating UML diagrams from LEM Steven Ring January 28, Introduction to LEM LEM is a Language for Executable Models based on the modelling language described by Mellor and Balcer [MBJ02] and generally know as Excutable UML or xtuml. LEM allows application modellers to record domain models as plain text files for subsequent processing by LEM compilers, translators and verifiers. 1.1 LEM authoring tools As plain-text files, xtuml models may be created, ameneded, copied, transmitted and published using the most simple of text-based tools. In addition, LEM files may be stored and tracked using modern source code version managements systems such as RCS, CVS, Cervisia, etc. In short, no special tools are required for creating, amending or viewing LEM models. 1.2 Literate modelling LEM itself is designed to be human readable. A properly constructed and fully narrated LEM model should be readily understood by both non-technical domain experts as well as experienced IT professionals. A typical LEM file will contain a complete, formal specification of the domain model intermixed with generous amounts of explanatory narratives. Thus, LEM models encourage and facilitate the practice of Literate Modelling described by Arlow and Neustadt [AN03]. 1.3 LEM syntax and grammar LEM is based on the complete xtuml meta-model (reference to Starr s original metamodel and work done by Ring et al) and is described by a formal syntax (reference to LEM grammar specification at LEM and the xtuml toolkit project LEM has been developed as part of suite of projects to be undertaken by software engineering students at ANU. These projects have been proposed by Shayne Flint and are described at flint 2.html In 2002, as part of her honours year thesis [Wal02], Emma Walker proposed a text based language to describe xtuml models. She called the language LEM based on a contraction of her nickname. Others later decided she really did want it to mean Language for Executable Models. 1

2 4 LEM EXAMPLE 2 In 2004, this author undertook the developement of a formal grammar and language parser for LEM [Rin04]. The parser and associated API were developed entirely in JAVA and were based on a formal xtuml metamodel. At the time of writing, the parser and API are substantially complete and the work is due for final completion in June The LEM project website can be found at 2 Problem Being a text-based language, LEM does not facilitate the presentation of models in the form of UML diagrams. While UML diagrams may be developed and used during the analysis phases, the final models are recorded exclusively as LEM text and the UML diagrams are lost. Whilst any xtuml model can be fully expressed in LEM, it is thought that the absence of UML diagrams in the final product may detract from the presentation of the models and make them less understandable to some, if not most, readers. Experience with modern modelling tools would suggest that the most effective form of model presentation is that which combines text definitions and narrative descriptions with the liberal use of supporting diagrams. 3 Solution The proposed solution involves the generation of UML diagrams directly from the LEM models. This solution will require the development of a JAVA program to be know as lem2uml. The diagram generator (lem2uml) will take a LEM input file and output one or more UML diagrams as encapsulated PostScript files. Diagrams created by the generator may be complete or partial representations of the input model depending on input parameters supplied to the generator. Figure 1 illustrates how lem2uml might work. Figure 1: Data flow in lem2uml 4 LEM example Figure 2 shows a simple model expressed in LEM.

3 5 PROJECT DEFINITION 3 1: // Model of the ideal marriage 2: // 3: // Source: 4: //================================================================================== 5: 6: model HumanSociety is 7: "concerned with many aspects of human life" 8: 9: domain Marriage is 10: "describes the concept of matramony as practiced in most 11: (but not all) parts of the world." 12: 13: subsystem People is 14: "concerned with people and the concept of marriage" 15: 16: object Person is 17: "a human being" 18: 19: attribute name 20: "the name by which a individual is known for legal purposes" 21: is string; 22: attribute birthdate 23: "the day on which the person was born" 24: is date; 25: end Person; 26: 27: object Male specialisation of Person is 28: "a person of the male gender" 29: end Male; 30: 31: object Female specialisation of Person is 32: "a person of the female gender" 33: end Female; 34: 35: // generalisation and associations 36: 37: generalisation R1 is 38: "the common notion that each person is either a male or a female" 39: Person is Male or Female; 40: end R1; 41: 42: association R2 is 43: "the concept that a man and woman may marry. 44: Some men do not marry and, likewise some women choose not to marry. 45: In most societies, marriage is an exclusive arrangement. For the 46: sake of a peaceful life a person should only be married to at most 47: one person at any one point in time" 48: 49: Male "has, as wife" 0..1 Female; 50: Female "has, as husband" 0..1 Male; 51: 52: object Marriage is 53: "the union of a man and a woman" 54: 55: attribute startdate "the date of the wedding" is date; 56: attribute enddate "the date of the divorce" is date; 57: attribute celebrantname "the name of the celebrant" is string; 58: attribute location "where the marriage took place" is string; 59: end Marriage; 60: end R2; 61: 62: end People; 63: end Marriage; 64: end HumanSociety; 5 Project definition 5.1 Vision Figure 2: Simple model written in LEM To create a useful LEM to UML diagram generator to allow LEM models to be enhanced via the inclusion of automatically created UML diagrams.

4 5 PROJECT DEFINITION 4 Person name :string birthday :date R1 Female 0..1 R2 + has, as husband Male + has, as wife 0..1 Marriage startdate :date enddate :date celebrantname :string location :string Figure 3: UML diagram generated from LEM input file 5.2 Tasks The project will involve the following tasks Requirements specification Analysis Design Development Testing and documentation 5.3 Deliverables The following deliverable are required in this project: Project vision and context statement Statement of Requirements (SRS) Analysis report Software design document Test plan

5 6 FUTURE DEVELOPMENT 5 Develop software User documentation, installation and JavaDoc Project summary report The lem2uml must be capable of generating the following core xtuml diagrams: Class diagram (information model) State transition diagram Domain diagram (domains and bridge lines only) 5.4 Prerequisites Students attempting this project should have the following prerequisites: a good understanding of xtuml having completed the COMP3110 course or its equivalent JAVA programming skills basic knowledge of UML 5.5 Main challenges The main challanges in this project will be: developing a good understanding of LEM, its metamodel, syntax and the LEM JAVA API spatial arrangement of objects in the UML diagram this will present a major challange for the developer. It may be possible to give the lem2uml program clues as to how the elements of the diagram could be arranged. The program will need to avoid collisions between objects on the page. learning and using JAVA s graphical API to generate postscript output 5.6 Key technologies The following lists the key technologies to be employed in this project: LEM grammar specification and metamodel JAVA programming language LEM API Graphics APIs and tools JavaDoc and Latex for documentation 6 Future development In the future, the diagram generator could be used as a component in a LEM fancy formatter. The fancy formatter would take a LEM file as input and output a document (EPS, HTML or other format) which contains both the original LEM text together with UML diagrams included at appropriate positions within the LEM text. Using this technique, aspects of the model could be described using partial UML diagrams which contain only those elements of the model under discussion at that point in the document.

6 REFERENCES 6 7 Related projects The following projects are related to this work Ongoing development of LEM, its syntax, metamodel and the LEM JAVA API LEM verifier project LEM repository project References [AN03] Jim Arlow and Ila Neustadt. Enterprise Patterns and MDA - Building Better Software with Archetype Pattterns and UML. Addison-Wesley Longman Publishing Co., Inc., [MBJ02] Stephen J. Mellor, Marc Balcer, and Ivar Jacoboson. Executable UML: A Foundation for Model-Driven Architectures. Addison-Wesley Longman Publishing Co., Inc., [Rin04] Steven Michael Ring. A formal grammar, language parser and java api for lem a language for executable models [Wal02] Emma Margaret Walker. A language for the specification of shlaer-mellor objectoriented analysis models