Uml is made similar by the presence of four common mechanisms that apply consistently throughout the language. After constructing or developing the architecture and different views of a software intensive system, the developer should go for common mechanisms. We have four types of common mechanisms. They are….  Specifications  Adornments  Common divisions  Extensibility

Adornments Adornments are generally added to an element’s basic notation and are used to visualize details from the element’s specification.They are used to decorate a particular thing to specify some artifacts. Adornments are classified into two types. They are….. 1. Textual adornments 2. Graphical or symbolic adornments. Textual adornments Most adornments are rendered by placing text near the element. Textual adornments are the strings which delineate the artifacts of a particular thing or relationship or a diagram. Some of the common textual adornments are name, role names, multiplicity, is aggregation or not.

Graphical adornments Most adornments are rendered by adding a graphic symbol to the basic elements. These are the adornments used to specify the artifacts such as relationships, access specifiers etc. some of the symbolic adornments are.. public private # protected note

A note is a special kind of adornment, which is a graphical symbol for rendering comments or constraints attached to an element or collection of elements. These are used to specify things like requirements, observations, reviews and explanations, in addition to rendering constraints. A note is rendered in uml using a rectangle with a dog-eared corner. In uml a note can be rendered in three ways. They are….. A note may contain some plain text Put an url inside a note Simple text An embedded url

We may link to or embed another document Extensibility mechanisms Uml has the capability of extending its vocabulary, properties, and semantics using one of the mechanisms known as extensibility mechanisms. This mechanisms permit us to extend the language in controlled ways. these mechanisms include… 1. stereo types 2. tagged values 3. constraints Link to document

constraints Tagged values Stereo types

A stereo type extends the vocabulary of the uml, allowing you to create new kinds of building blocks that are derived from existing ones but with its own properties, semantics and notation. in simplest form a stereo type is rendered as a name enclosed by guillements define an icon for the stereotype and render that icon to the right of the name > ModelElement Named stereotype > underflow ! Named stereo type with icon

Render an icon as a basic symbol for the stereo typed item Tagged values A tagged value extends the properties of a uml building block, allowing to create new information in that element’s specific function. A tagged value is rendered as a string enclosed by brackets and placed below the name of another element. That string includes a name(tag), a separator(=) and a value( of the tag). Stereotyped element as icon Server {processors=3}

Constraints A constraint is a condition which is used to add or modify the existing rules or semantics for a well-formed model we need to have certain constraints established. A constraint is generally rendered as a simple statement or a mathematical equation in a pair of curly braces, and is placed by side of the thing to which it belongs. simple constraint portfolio Bank Account corporation Gender :{f,m} person {secure} {or} Constraint across multiple constraints {self.wife.gender=female and Self.husband.gender=male} Formal constraint Using ocl

based on the common mechanisms we can model the following modeling comments modeling new building blocks modeling new properties modeling new semantics Modeling comments write the comment in the symbol provided and place the note by side of the element to which it refers. the note can be elided or it can be made visible if the note is lengthy, then write down the complete description in a document and place a link in the note referring the document as the model evolves keep those comments that are significant, otherwise remove

Modeling new building blocks Make sure that the thing which we want to model doesn’t have a graphical representation in uml After conforming the above select any one of the eleven things and stereotype it. Stereo typing can be done in two ways. 1. Selecting a stereo type which already exists. 2. Creating our own stereo type. Specify new properties and semantics for the new thing. If necessary place a icon for the above stereo type

Modeling new properties Make sure that there is no way to express a value using the attributes of a class In the above situation create a new tag and assign it a value which we want to model > FieldAccess {version=2.5 Status=checkdin} > FieldAccess {version=2.5 Status=checkdin} > Billing {version=3.2 Status=checkout By=edg} > Billing {version=3.2 Status=checkout By=edg} > AccountsPayable {version=3.2.1 Status=checkedin} > AccountsPayable {version=3.2.1 Status=checkedin} > WorldCurrency {version=7.5 Status=checedin} > WorldCurrency {version=7.5 Status=checedin} 

Modeling new semantics M ake sure there is no way to model the rules of constraints. Write down the constraints and new semantics for the element which we want to model and place adjacent to it If we want to express the constraints in a more precise way use ocl as apart of mentioning the constraints member 1..* 1 manager department person {subset} <

END.