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3. How are the terms type and interface related? |
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A type is realized through the interface of a class. For instance, a checking account is a type of bank account. Notice the use of the word type. An interface of a class describes its type. For example, when you say CheckingAccount is a type of BankAccount, you are saying that the former inherits the interface of BankAccount. So if BankAccount has a public method deposit, CheckingAccount implements that same method in its own unique way, if necessary. |
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4. How do you realize interface inheritance in Visual Basic? |
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You realize interface inheritance by using the Implements <name of interface class> keyword in the class module of the implementation class. |
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5. What's the difference between collection and aggregate objects? |
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An aggregate object is composed of one or more objects that are an integral part of that object. A collection of objects holds references to one or more objects that are loosely coupled. That is, a collection can hold references to any kind of object, and the lifetime of those objects are not dependent on the collection itself. |
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6. What are methods, accessors, and mutators? |
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Methods are nicely encapsulated series of code instructions that enable access to implemented behavior. Accessors give an object's clients access to its property value. Mutators give an object's clients access to set its property values. |
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7. What's the difference between a subsystem and a category? |
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The logical representation of a subsystem is called a category, although this sometimes leads to confusion between the two. The distinction between the two is a relic of C++ programming, with the separate header and implementation files that map to one logical class. For Visual Basic, a class interface and implementation are stored in one file, so there is no real distinction. Thus, a subsystem of five class files maps directly to a category of five classes. |
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8. What is a class diagram? a sequence diagram? |
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A class diagram shows the unique identity of one or more classes, their behaviors, and any inheritance, delegation, or aggregation relationships. Scenario diagrams (along with collaboration diagrams) capture how the instances of these classes interact at runtime to carry out some system behavior. Because of the easy-to-follow nature of these types of models, complex systems can be broken down into simpler abstractions. Together, they provide the architectural expression of the proposed system. |
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