® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited An Introduction to ISO STEP Part 25 David Price

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Agenda Why Part 25? EXPRESS/UML Mapping Future

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Why Part 25? The ISO EXPRESS language has been used by the STEP, POSC, EDIF and other data modelling communities for 15 years Since the OMG standardized UML, it became a widely used software engineering language Part 25 is designed to allow software engineers using UML to reuse schemas modelled using EXPRESS

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited How? Define mapping into OMG standards –OMG defined a subset of UML for use in defining modeling languages Meta-Object Facility or MOF –OMG defined an XML encoding of anything modeled using MOF XML Metadata Interchange or XMI –OMG defined a model of the UML language using MOF “UML Model Interchange” Model

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited The Part 25 Vision Model Information Change Environment Model Software Generate Software SCHEMA people; ENTITY person; name : STRING; END_ENTITY; ENTITY organization; name : STRING; members : SET OF person; END_ENTITY; END_SCHEMA; Start with an EXPRESS schema of the data requirements of the domain of interest

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited The Part 25 Vision Model Information Change Environment Model Software Generate Software Translate EXPRESS into XML Metadata Interchange format (XMI)

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited The Part 25 Vision Model Information Change Environment Model Software Generate Software Use UML software engineering tools to model the complete software system Person Organization

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited The Part 25 Vision Model Information Change Environment Model Software Generate Software Generate much of the application in the programming language of choice public Person { } public Organization { }

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Conformance EXPRESS text or XML parser EXPRESS to UML metamodel XMI syntax for UML metamodel Specified in Part 11 or 28 Specified in Part 25 Specified in XMI Part 25-based EXPRESS to UML/XMI tool EXPRESS schema text or XML EXPRESS language DTD XMI-compliant UML DTD XMI encoding of UML mapped from EXPRESS schema controls if XML controls

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Mapping Requirements The mapping was designed with “software engineering using UML” in mind –Round-trip, completely interoperable EXPRESS/UML translation was not a requirement for Edition 1 –Consider UML an abstraction of Java, C++, etc. 80/20 rule and don’t “surprise” people who know both languages Part 25 defines a one-way mapping from EXPRESS 1 to UML 1.5 –Based on the meta-model of UML, not the diagrams

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Mapping Approach Mapping is viewed from a “context schema”, the top-level schema you want to implement –Schemas using other schemas are mapped correctly –Anything not visible in context schema is ignored Map into native UML concepts on a “Static Class Diagram” –“vanilla” UML is the result –as round-trip not required, the fact that the UML started life as EXPRESS is mostly lost

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Class Diagram Example Association Package Class Generalization Attribute

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Mapping Issues UML Associations must be SETs –Only SET and LIST OF UNIQUE can map to Association No built-in support for nested aggregation types What is a select type? Default for UML Generalization is disjoint/ONEOF, but is ANDOR/overlapping in EXPRESS

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Not Mapped RULE declarations domain rules in ENTITY or TYPE declarations UNIQUE rules in ENTITY declarations SUPERTYPE declarations other than ABSTRACT SUPERTYPE and complete ONEOF constraints FUNCTION declarations PROCEDURE declarations CONSTANT declarations explicit attributes redeclared as derived attributes remarks

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Mapping Schema, Entity, Type SchemaUML Package USE FROM and REFERENCE FROM and AS UML ElementImport and Alias ENTITY and SUBTYPE OF and ABSTRACT SUPERTYPE and ONE OF UML Class and Generalization and isAbstract and disjoint TYPE x = SELECTUML Class and Aggregation Association named “selection_of” TYPE x = ENUMERATIONUML Enumeration and Enumeration Literals TYPE x = not SELECT and not ENUMERATION UML Class and Generalization with representation of underlying type being the parent

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Mapping Attributes explicit attribute of simple data type and OPTIONAL UML Attribute with corresponding type and Multiplicity set explicit attribute of type ENTITY or TYPE reference and OPTIONAL and INVERSE UML Association between Classes with Multiplicity set and reverse Multiplicity set as in INVERSE explicit attribute of type SET or LIST OF UNIQUE ENTITY or TYPE UML Association between Classes with multiplicity set as bounds redeclared explicit attribute specializing domain to a subtype OCL Constraint explicit attribute of type other aggregation of ENTITY or TYPE UML Multi-valued Attribute (UML Associations must be sets) derived attributeUML derived Attribute or Association

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Mapping Aggregates and Datatypes LIST or SET of simple type (referenced from TYPE or attribute) UML Class named List-of-xxx or Set- of-xxx nested aggregationsUML Class named Set-of-Set-of-xxx and aggregation association named aggregation_of STRING and INTEGER and BOOLEAN UML String and Integer and Boolean NUMBER and REALDouble equivalent to MOF/IDL, there is no native UML Double BINARYCreate new DataType called Binary, there is no native UML Binary LOGICALUML Enumeration and Enumeration Literals

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited The Reverse UML Package –Schema UML Class –Entity Type –Select Type –Other Defined Type except Enumeration Type –Nested Aggregate Type (referenced from UML Attribute or Association) –Simple Datatype (one option) UML Enumeration –Enumeration UML Association –single-valued explicit attribute : named type –SET or LIST OF UNIQUE : named type UML Attribute –all explicit attributes not mapped to UML Association

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited EXPRESS (1) SCHEMA STEP_demo; TYPE approval_assignment = SELECT ( Product, Product_version ); END_TYPE; ENTITY Product SUPERTYPE OF (ONEOF ( Requirement ) ); id : STRING; name : STRING; description : OPTIONAL STRING; versions : SET[1:?] OF Product_version; END_ENTITY; ENTITY Requirement SUBTYPE OF ( Product ); END_ENTITY;

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited EXPRESS (2) ENTITY Product_version; id : STRING; name : STRING; END_ENTITY; ENTITY Product_category; id : STRING; name : STRING; products : SET[0:?] OF Product; END_ENTITY; END_SCHEMA;

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Example UML

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Nested aggregate EXPRESS ENTITY our_entity; our_matrix : ARRAY[1:3] OF ARRAY[1:3] OF REAL; END_ENTITY;

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Nested Aggregate UML

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Use of OCL Redeclared explicit attribute of_product in system_version results in OCL Constraint with Name and Body

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Redeclared explicit attribute ENTITY system_version SUBTYPE OF ( product_version ); SELF\product_version.of_product : system; END_ENTITY; Constraint Name redeclaredsystem_versionof_product Constraint Body context system_version inv redeclaredsystem_versionof_product : self.of_product -> forAll ( oclIsTypeOf ( system ) )

® Eurostep.ESUKPC v0.1©Copyright Eurostep Limited Future Edition 2 planning, ideas are: –Add support for EXPRESS 2 (highest priority) –Define EXPRESS using the OMG Meta-Object Facility (now called UML Infrastructure or Core) Result will be EXPRESS as one of the UML family of languages or ability to use EXPRESS in some UML tools natively –Support UML 2 –UML Profile for EXPRESS Allow use of UML class diagram instead of EXPRESS-G Supports UML to EXPRESS and perhaps round-trip metadata interchange –Further use of OCL in the mapping