Lecture 8

Question 1

What is a structural model?

Answer 1

Capture the structure of a system. Elements and their connection can be perceived even without executing the system

Question 2

Software modeling helps in establishing what?

Answer 2

The context and (intended) functionality of a system

Question 3

What are the steps of relevance of modeling in software development.

Answer 3

Analysis: Use uniform notation for use cases, unify terminology.
System Design: Create coarse-grain system structure, abstract for decision-making.
Detailed Design: Develop fine-grain system design, specify and agree on behavior.
Implementation: Models as implementation specs.
Quality Assurance: Ensure implementation matches models, use for testing behavior.
Maintenance: Evaluate changes based on model feasibility/effort.

Question 4

what should models abstract from?

Answer 4

Details and instead focus on the “design essence” of the system

Question 5

Which UML (unified modeling language) diagrams are structured?

Answer 5

Class diagram
Object diagram
Deployment diagram

Question 6

What does UML stand for?

Answer 6

The Unified Modeling Language (UML)

Question 7

Mention the main diagram types of the UML.

Answer 7

Structure diagram
Behaviour diagram
(Interaction diagram)Her

Question 8

How would you describe the process of creating an UML class diagram?

Answer 8

Purpose: Create a general software system design focusing on essential problem-solving.
Process: Start with a high-level design, refine to detailed implementation.
Focus: Abstract technical details to prevent getting lost in technology discussions, emphasizing domain challenges

Question 9

What is UML?

Answer 9

• Standard defining meta model for software modeling
• Standard specifying model concepts and their relations

Question 10

Give an example of what a class diagram (single box) might look like:

Answer 10

Her

Question 11

What the UML is not:

Answer 11

• A graphical language standard (only suggestions)
• A model with formal semantics (instead interpretation using common sense)

Question 12

What are associations in UML class diagram?

Answer 12

Reference to another class (entities) Her

Question 13

What is meta model?

Answer 13

A meta model captures the syntactic elements and their potential relations. You can think of this as the blueprint of a language that tells you which concepts can be expressed
(vocabulary) and in which way they may be combined (grammar).

Question 14

What is a role in an UML class diagram?

Answer 14

A class playing a role
her

Question 15

What are the three visibility modifiers, and their symbols?

Answer 15

Protected #
Private -
Public +

Question 16

What is an association, association class and association name in UML class diagram?

Answer 16

Association: Reference to another class’
objects.
Association class: Additional information for association
Association name: In middle of association, and is in the reading direction
her

Question 17

What is a Class Member? How is that declared?

Answer 17

• Underlined
• Same value/declaration for all objects of class
• Similar to static in Java

Question 18

How do you write attributes, methods and parameters in an UML class diagram?

Answer 18

vis.mod = visibility modifer
Attributes: vis.mod. <name> : <type>
Methods: vis.mod. <name>() : <type>
vis.mod. <name>(<parameters>) : <type>
Parameters: Similar to attribute

Question 19

Is it okay to omit visibility modifiers/types/names?

Answer 19

Yes, class diagrams provide a lot of liberty in regard to providing names, types, visibility modifiers: eg, visibility modifiers or types may be omited altogether for early design phases

Question 20

What is an multiplicity in UML class diagram?

Answer 20

Lower bound, e.g., 0 or 1
Upper bound, e.g., 5 or *
(remember ER diagrams in databases)
Her

Question 21

Write down the diagram type, modeling of, purpose and benefits of an UML class diagram

Answer 21

Diagram type: Structual diagram
Modeling of: classes, interfaces, relations
Purpose: Abstraction from, so individual objects via classes and details for design
Benefits: Modeling a subsystem for analysis and design. Reverse engineering existing system design for overview
her

Question 22

What kind of relationship does aggregation imply?

Answer 22

a relationship where the child can exist independently of the parent (unlike composition). Example: Lecture (parent) and Student (child). When you delete the Lecture, the Students still exist.

picture

Question 23

What is association, aggregation and composition in UML class diagram?

Answer 23

Association: References
Aggregation: owns but does not manage lifecycle
Composition: own and managaes lifecycle
her

Question 24

What is a composition in regards to class diagrams? What does it look like?

Answer 24

A composition is a special case of an association. A composition means that objects of the referenced class are “owned”. (unlike plain associaions but similar to aggregation).

It looks like a filled diamond on a line with an arrow in the other end.

picture

Question 25

What are interfaces, enumerations and stereotypes in UML class diagram?

Answer 25

Interface: `<>` (written using stereotypes (<<>>) (DRAWN WITH DASHED LINE, IMPLEMENTS) Enumeration: `<>` (written using stereotypes (<<>>) Stereotype: Written using <<>> [Her](https://docs.google.com/document/d/1nCFl2l3Mkua4Sqc8ThVE_jpHbIjnJi4il3Hdh2CuG5A/edit)

Question 26

What kind of relationship does compositon imply?

Answer 26

A composition means that the referenced object is "part-of" the referencing object (unlike aggregation). In other terms, the referencing object manages the lifecycle of the referenced object.) [picture](https://docs.google.com/document/d/14NHPfZN8JMx57d65mqfnAUKIwQ2071qzfU5Gdbkng10/edit)

Question 27

How does generalisation look like in an UML class diagram?

Answer 27

[Full line empty arrow pointing at the superclass](https://docs.google.com/document/d/1nCFl2l3Mkua4Sqc8ThVE_jpHbIjnJi4il3Hdh2CuG5A/edit)

Question 28

How does he UML Generalization denotes inheritance?

Answer 28

Generalization (super class) and specialization (sub class)

Question 29

Difference between classes and objects (UML diagrams) and how to draw?

Answer 29

Class: Description of similar elements. Object is an instance of a class Object: Concrete, individual element. Maintains (unchangeable) identity after creation [Her](https://docs.google.com/document/d/1T3FGLIk8ThpnV_0CJV0FQa1FIl0H2J4KIGRCp5d_AKM/edit)

Question 30

How does class diagrams denote abstract methods/classes?

Answer 30

Writng them in italics. However, for hand-drawn UML diagrams, this is somewhat impractical because it is hard to distinguish italics in hand-writing. In such a case, , it may be helpful to add a comment stating that the respective element is abstract.

Question 31

Difference between UML and Java (protected visbility, inheritance, association type, association classes)

Answer 31

UML **Protected visbility**: Visible only for class and subclasses **Inheritance**: Multiple **Association types**: Association, Aggregation, Composition **Association classes**: Directly supported Java: **Protected visbility**: Visible for class, subclasses and same package **Inheritance**: Single **Association type**: Reference **Association class**: Need to be emulated

Question 32

What phases are likely to yield what diagrams?

Answer 32

Analysis (requirement engineering) = use case diagram Coarse-Grain Design and fine grain = class diagram implementation = code

Question 33

Write down the diagram type, modeling of, purpose and benefits of an UML deployment diagram

Answer 33

**Diagram type:** Structual diagram **Modeling of**: physical deployment of artifacts on nodes **Purpose**: Show which parts of a distributed application run on which parts of the infrastructure. **Benefits**: Specify distribution of software. Determine necessary hardware infrastructure. Devise communication strategies [her](https://docs.google.com/document/d/1xPbKEalP94DrVkePXCryeel8nagxZHDr-IZC0TrD-0c/edit)

Question 34

Difference in fine-grain and coarse-grain desing?

Answer 34

**Coarse-grain** class design may be relatively informal: Names may be informal in syntax. Types may be omited, esp. the (technical) return type void. **Fine-grain** class design has to be specific so that it can serve as basis for implementation.

Question 35

What is an artifact in UML deployment diagram?

Answer 35

Artifact: A piece of software (component, object, document, etc,) It's deployed to nodes [Her](https://docs.google.com/document/d/1lTaRtpUHqjCMj8HCtsS78ojWvzzRLfhwKns-6UBaYdM/edit)

Question 36

Draw a UML program for this: [Here](https://docs.google.com/document/d/1milvZJS35IVUsJKastwC3dzDDgoeitHiE2fiAufxkoQ/edit)

Answer 36

[Solution under](https://docs.google.com/document/d/1milvZJS35IVUsJKastwC3dzDDgoeitHiE2fiAufxkoQ/edit)

Question 37

Name these things:

Answer 37

[Her](https://docs.google.com/document/d/1xHMA9a-r4oHam-UIfi8YALmQTLrCM9gzESdRpUwqOhY/edit)

Question 38

Characteristics of object diagrams:

Answer 38

Structural Diagram, models objects (class instances), show example of objects with their specific values. Good for: * Talk about system states with concrete values for objects. * Integrate with behavioral notations that explain system execution via examples.

Question 39

Draw a simple object diagram

Answer 39

[answer](https://docs.google.com/document/d/1dw4Om2T0AI0Z3qvExmIEw3qvAunii93YPRvgCuavbVA/edit)

Question 40

Is the name of an object mandatory (object diagram)?

Answer 40

No, an anonymous object can be displayed instead, e.g., ":Engine".

Question 41

What does a node describe in deployment diagrams?

Answer 41

An "instances" of specific pieces of hardware, e.g., a web server, a laptop or a database server. Nodes may have attributes (RAM ect) and nodes can be nested. (sub-nodes)

Question 42

Take home message:

Answer 42

* UML Class Diagrams: Fine-grained specification of system structure. * UML Object Diagrams: Example of system state via instances * UML Deployment Diagrams: Distribution to physical components.

Question 43

What is an aggregation in regards to class diagrams? What does it look like?

Answer 43

An aggregation is a special case of an association. An aggregation means that **objects of the referenced class** are "**owned**" (unlike plainassociations but similar to composition). It looks like a empty diamond on a line with an arrow in the other end [picture](https://docs.google.com/document/d/14NHPfZN8JMx57d65mqfnAUKIwQ2071qzfU5Gdbkng10/edit)