Generation and Implementation. More on classes Types Implementation classes Interfaces Templates...

Generation and Implementation

More on classes

• Types

• Implementation classes

• Interfaces

• Templates

• Associations– Dependencies– Compositions

Type classes

– are classes that are defined as a collection of operations without methods.

– They are used to model a collection of operations applicable to different classes of objects.

– are denoted as stereotyped class rectangles.– are equivalent to abstract classes with no method and

only abstract operations.– Must be stereotyped using the <<type>> keyword.– Are implemented by implementation classes.– May have generalisation relationships to other types.

‘AppleScript’ type classes

• AppleScript is a scripting system that allows you to directly control Macintosh applications

• It provides Unit Type value classes for working with measurements of length, area, cubic and liquid volume, mass, and temperature.

Unit Type value classes

Length Area Cubic volume

Liquid volume

Weight Temp-erature

Centi-metres

Square feet

Cubic feet Gallons Grams Degrees Celcius

Kilometres Square kilometres

Cubic yards

Litres Kilograms Degrees Fahrenheit

Feet Square Metres

Cubic metres

Quarts Ounces Degrees Kelvin

Inches Square miles

Cubic metres

Pounds

Metres

Miles

Implementation classes

– are denoted as stereotyped class rectangles.– Must be stereotyped using the <<implementation

class>> keyword.– May implement other classes via a ‘realises’

generalisation relationship from the implementation class to the implemented class.

• The implementation class inherits operations but not structure (attributes / associations)

– May also have generalisation relationships to other implementation classes.

Implementation classes

• These classes often do not relate to classes in the real-world domain.

• They are the ‘scaffolding’ classes that support the domain (boundary, control and entity) classes.

• An example would be a collection object to organise and maintain references to all objects in a collection. – This would be necessary to compile lists for scroll

boxes, aggregate derived fields, etc.

Interfaces

Interfaces

• These are classes that define a set of externally accessible operations without methods. They are used to model a collection of operations defining a service that may be offered by different classes.– Something like an external view in a database.

• Denoted as stereotyped class rectangles, or a small circles with the name of the interface attached.

interfaces

• Are equivalent to abstract classes with no attributes and no methods and only abstract public operations.– Must be stereotyped using the <<interface>>

keyword.– Must not have an attribute compartment.– Must not have associations.– Must have an operation compartment

containing the interface’s operations.

interface• The text editor uses a

platform-independent interface, window.

• The window is an abstract class, defining the functionality required of the window, but not providing it.

• The specialised classes are concrete implementation classes. These provide the functionality for window

• Java uses the word ‘implements’ to show this.

•May be used by other classes via a dependency stereotyped using the <<uses>> keyword.

Text editor Window

tofront()toback()

WindowsWindow

toFront()toBack()

X11Window

toFront()toBack()

MacWindow

toFront()toBack()

Another depiction…Text editor

Window

tofront()...toback()...

WindowsWindow

toFront()toBack()

X11Window

toFront()toBack()

MacWindow

toFront()toBack()

• May have generalisation relationships with other interfaces.

• May be supported by other classes via a ‘realises’ generalisation relationship from the supporting class to the interface class.– The supporting class must offer all the

operations defined in the interface class, and may offer new operations.

Templates

Templates / Parameterised classes

• These define a family of classes having a common form. • The differences between classes in the family are

represented by parameters, allowing a single template to instantiate many classes.

• Specific classes within this family are defined by specifying actual values that are bound to formal parameters.

• In the template, the parameters are unbound or unspecified.

• Also known as a parameterised class.

Templates / Parameterised class

• We want a class to list students and we want a class to list games.

• This could be done using two separate classes called StudentList and GameList, but they would have a lot in common.– Add element to the list.– Delete element from the list

• However, define List (T), which, given a class C to substitute for the formal parameter T, describes the class of lists of C objects.– an object of class List <Student> represents a list of students,– whereas an object of class List <Game> represents a list of

games.

Example

• A template class is shown as a class with a small dashed rectangle in the top right hand corner, which holds the formal parameters.

T

List

insert()remove()

Dependency

• Is denoted by a dashed arrow with the arrowhead pointing at the independent element.

• Relates elements of a model.• Don’t require instances to associate; they

exist among the model elements.• Have elements that exist at the same level

of abstraction or at the same level of detail.

• May be stereotyped using the <<refinement>> keyword to depict different semantic levels of abstraction. The refinement may be described in a note attached to the dependency.

• May serve as a container for a group of dependencies from parts of a client element to parts of a supplier element.

Dependency

• An association relationship is a dependency relationship when the object requesting (client object) the service of another object (server object) does not have intrinsic knowledge of the location of the server object - it must be told where the object is located.– Typically,

• either the server object is passed as a parameter to one of the methods of the client class

• or the server class is declared locally within a method of the client class.

Further exampleInputStream

<<Interface>>

DataInput<<Interface>>

OrderReader

DataInputStream

• The InputStream and the DataInput are abstract interface objects.

• The link between OrderReader and DataInput is a dependency.

• It shows that OrderReader uses the DataInput interface for some purpose.

• The link between DataInputStream and DataInput is a refinement. This indicates a greater level of detail.

Generalisation

Dependency

Refinement

Generating Code

From your ROSE model

Set up your path

• Create a directory for this work, such as U:\ROSE\StudentCode

• Edit the model properties (Tools>Model Properties>Edit)

• Click the Notation tab and choose Java as the default language.

• Set up the class path (Tools>Java>Project Specification

• Click the ‘new folder’ icon.

• Click the three dots.• Browse to find the

correct directory.

• Click OK• When the correct

directory is shown, click Apply.

For each class to be generated…

• Package classes– E.g. place all classes into a single package.

• Later, we will discuss strategies for packaging.

– To do this, add a package to the logical view and drag all the classes you need into it.

– Select each class and click Tools>Java>Generate Code

– Click Assign to assign your class to the chosen class path.

– You may get generation errors.

Typical errors

• Errors occur due to incompatibility between your model and the target language.

• E.g.– 10:44:57| WARNING: Class Logical View::OM_claim::Accident - the name

of attribute Accident date/time is not a valid Java identifier.10:44:57| ERROR: Class Logical View::OM_claim::Accident - a name which is a valid Java identifier cannot be constructed for attribute Accident date/time10:45:16| Starting Code Generation10:45:16| WARNING: Class Logical View::OM_claim::Accident - the name of attribute Accident date/time is not a valid Java identifier.10:45:16| ERROR: Class Logical View::OM_claim::Accident - a name which is a valid Java identifier cannot be constructed for attribute Accident date/time

• Note, these are errors due to an incompatibility between the given names and the Java language.

– i.e. you cannot call a field “Accident date / time”.

Error handling• Return to the class diagram and

fix the problems. • Generate again. This dialogue is

displayed:Insert a new classpath as shown on the next slide

• Returning to the Classpaths dialogue, click on the component and click ‘Assign’.

• The component then disappears from the RHS of the screen.

• When the code generation is complete, hopefully you will get ‘Code generation completed successfully’

• The following code has been generated into the folder: <folder name>

Data model generation

Using SQL Server

Converting classes to tables

• Classify the classes, using a 3-tier system– Tick the ‘Three-tier diagram’ box in the tools - options

menu in Rational Rose.

• Move all persistent classes into a single package.

• For each persistent business class:– Open the standard specification– Select the ‘detail’ tab– Turn on the ‘persistent’ radio button.

Using the Data Modeler

• Using the component view– Set up a database

• Right click on component view, choose data modeler, new, database.

– Open the specification for the database and choose the target database depending on the implementation route (e.g. SQL Server 2000)

• In the logical view– Set up a new schema

• Right click on logical view, choose data modeler, new, schema.

• Open the schema specification.• Associate it with the database you have created.

• Right click on the package in the Logical view

• Choose data modeler• Choose ‘Transform to

data model’• Fill in destination

schema and target database.

Result

• This creates a set of tables in the database.

• You can view them by setting up a new data model diagram.– Right click on schema– Choose data modeler– Choose new– Choose data model diagram

T_AssessorUsername : SMALLINTPassword : SMALLINTT_Assessor_ID : INT

<<PK>> PK_T_Assessor1()

T_AccidentAccident date/time : SMALLINTAccident location : SMALLINTAccident description : SMALLINTBus registration : SMALLINTT_Accident_ID : INT

<<PK>> PK_T_Accident0()

T_ClaimantClaimant name : SMALLINTClaimant address : SMALLINTDateOfBirth : SMALLINTT_Claimant_ID : INT

<<PK>> PK_T_Claimant3()

T_ExpertExpert name : SMALLINTExpertise : SMALLINTContact details : SMALLINTT_Expert_ID : INTT_Claim_ID : INT

<<PK>> PK_T_Expert4()<<FK>> FK_T_Expert2()<<Index>> TC_T_Expert5()

T_Expert ReportReport date : SMALLINTReport content : SMALLINTDate requested : SMALLINTT_Expert Report_ID : INT

<<PK>> PK_T_Expert Report5()

T_PaymentPayee : SMALLINTPayment amount : SMALLINTPayment status : SMALLINTPayment reason : SMALLINTAuthoriser : SMALLINTIssuer : SMALLINTT_Payment_ID : INTT_Claim_ID : INT

<<PK>> PK_T_Payment6()<<FK>> FK_T_Payment1()<<Index>> TC_T_Payment3()

T_Claimclaim reported date : SMALLINTclaim state : SMALLINTclaim type : SMALLINTT_Claim_ID : INTT_Accident_ID : INTT_Claimant_ID : INT

<<PK>> PK_T_Claim2()<<FK>> FK_T_Claim3()<<FK>> FK_T_Claim0()<<Index>> TC_T_Claim7()<<Index>> TC_T_Claim1()

1

0..*

1

0..*<<Non-Identifying>>

1

1..*

1

1..*

<<Non-Identifying>>

0..1

0..*

0..1

0..*

<<Non-Identifying>>

1

0..*

1

0..*

<<Non-Identifying>>

Generating SQL

• Right click on the database

• Choose Data modeler

• Forward Engineer…