1. Arab Open University 2nd Semester, 2006-2007 M301 Unit 5
Arab Open University 2nd Semester, M301 Unit 5.1 From Model to Implementation

2. Topic Road Map  Moving towards Implementation
From Requirements to Code
Controlling Inheritance
Using Tools to Automate Development
Modeling Implementation and Deployment
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3. When do you stop modeling?
When it is easier to construct code than building more models.
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4. Using activity diagrams for operations
Show the flow of control from one activity to another.
Used to investigate the different scenarios in a use case.
Show the steps required to collect the set of rules governing an operation.
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5. Class model shows payments made against a hotel bill
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6. A set of rules for payment authorization
The hotel need to authorize a payment by cheque or credit card.
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7. Sequence diagrams
Used to illustrate the possible scenarios for performing a use case.
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8. An example of cheque authorization
One of the hotel’s managers, John, has authorized a cheque, p101, for payment against a bill, b99.
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9. Topic Road Map Moving towards Implementation
 From Requirements to Code
Controlling Inheritance
Using Tools to Automate Development
Modeling Implementation and Deployment
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10. From requirements to implementation
Pre- and post-conditions were recoded in natural language.
If you want to incorporate them into Java code as executable statements, you will need to express them in the Java language.
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11. Assertion
A statement that can be true or false in a similar way that a Boolean expression will be either true or false in Java.
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12. An ‘extended’ Java syntax for an assertion handling
@pre indicates the value of the expression when the method started its execution.
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13. The absence of pre- or post- conditions
This does not mean that no pre-condition applies: it is simply a way of saying that the pre-condition is true.
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14. Not all assertions are easy to express in a programming language
If it is not possible to express an assertion formally (in a programming language) it is good practice to include it informally (in natural language).
This can be done by including its natural language version as a comment in the appropriate pre, post or invariant clause.
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15. … Not all assertions are easy to express in a programming language
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16. Invariants and their relationship to pre- and post-conditions
The invariant is considered as part of both the pre- and the post-conditions.
Before a method can be executed both the invariant and the pre-condition must hold.
After the method has completed, the invariant and the post-condition must hold.
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17. The supplier code The implementation (code) of a method.
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18. The client code How to call the method?
Suppose that acct1 is an object of type BankAccount.
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19. Monitoring assertions
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20. Topic Road Map Moving towards Implementation From Requirements to Code
 Controlling Inheritance
Using Tools to Automate Development
Modeling Implementation and Deployment
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21. Forms of Inheritance Inheritance for Specialization. Specification.
Construction.
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22. Inheritance without redefinition of methods
Since SavingsAccount and SpecialSavingsAccount are related via generalization, it means that an object of class SpecialSavingsAccount is-a object of class SavingsAccount.
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23. … Inheritance without redefinition of methods
The methods that SpecialSavingsAccount inherits from SavingsAccount have the same contracts as those in SavingsAccount.
Inheritance without redefinition guarantees that this will be the case.
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24. Inheritance with redefinition
Redefined methods automatically inherit the pre- and post-conditions of their parent methods.
Any invariant clause of the parent class should also be inherited by the child class.
addInterest ()
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25. Topic Road Map Moving towards Implementation From Requirements to Code
Controlling Inheritance
 Using Tools to Automate Development
Modeling Implementation and Deployment
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26. Definitions
Engineering: generic term often used to describe the building of an artifact (e.g. software, car, rocket) from some kind of model.
Forward engineering: is a synonym for the engineering process that is often used in CASE tools.
Code generation: the normal forward engineering process which automatically generates code.
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27. ... Definitions
Reverse engineering: is the derivation of a model from an artifact (which, in the case of S/W engineering is usually source code).
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28. ... Definitions
Round-trip engineering: going from model to code and back again (perhaps repeatedly) to ensure the consistency between model and code.
Simultaneous round-trip engineering: edit code or model and have the other updated automatically.
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29. Topic Road Map Moving towards Implementation From Requirements to Code
Controlling Inheritance
Using Tools to Automate Development
 Modeling Implementation and Deployment
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30. Nodes (processing resources)
Run-time, physical objects which have at least a memory and often processing capability as well.
Nodes include:
computing devices.
human resources.
mechanical processing resources.
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31. Real-world constraint on how a system may be built and maintained
The current capabilities of the technology and probably the budget of the customer.
Non-functional requirements, such as response time or robustness, cannot be modeled.
The programming language and the environment in which it is coded and documented.
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32. Component
Any distributable part of a system, which might include executable software, source code for the software, user manuals or documentation, or even a specialized piece of hardware.
If an object can be touched, or stored on a medium that can be touched, then it can be a component.
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33. Component Symbol
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34. A simple component diagram showing a dependency
class
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35. Simple Java program & its corresponding component diagram
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36. Deployment diagram
Indicates only the components that are active at run-time.
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37. Deployment diagram for home banking
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38. Packages
class
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39. TMA5 – Q1

40. Thank You!