L5 - Design Goals

Question 1

Concurrent Threads can lead to …

Answer 1

race conditions

Question 2

Façade Pattern

Answer 2

Provides unified interface for a subsystem + consists of a set of public operations + makes use easier

Question 3

Deployment Diagram

Answer 3

illustrates distribution of components on concurrent processes at runtime

Question 4

Access Control Matrix

Answer 4

Models access of actors on classes: actors (rows) + classes (columns) + entry (access right)

Question 5

Global Resource Handling

Answer 5

Describes access rights for different actors. Tool: Access Control Matrix

Question 6

Concurrency

Answer 6

Addresses nonfunctional requirements (e.g.: performance/latency) + can lead to starvation/deadlocks/fairness

Question 7

Hardware/Software Mapping

Answer 7

Mapping object model on hardware & software

Question 8

Boundary Conditions

Answer 8

Initialization + Termination + Failure

Question 9

Remote Proxy

Answer 9

Caching of information. Proxy object as local representative for an object in different address space. No frequent information change.

Question 10

Persistent Data Management

Answer 10

Data is persistent if the values of their attributes live beyond execution (file system: many readers/1 writer OR database: concurrent writers and readers)

Question 11

Global Access Table

Answer 11

Represents non-empty cell by triple (actor; class; operation): LeagueOwner; Arena; view()

Question 12

Physical Concurrency

Answer 12

Threads provided by hardware (multiprocessors/multicores)

Question 13

Thread Of Control

Answer 13

Path through a set of state diagrams where only a single object is active at any time

Question 14

Centralized Software Control

Answer 14

Fork Sequence Diagram: Procedure-Driven (control in code) OR Event-Driven (control in dispatcher) OR ‘Spider’ (1 control object)

Question 15

By what is a class/a class attribute and an instance of a class modeled when mapped to a database?

Answer 15

table (class) - column (class attribute) - row (instance of class)

Question 16

Logical Concurrency

Answer 16

Threads provided by software

Question 17

Capability

Answer 17

Associates pair (class; operation) with an actor: Arena; view() with LeagueOwner

Question 18

Component Diagram

Answer 18

illustrates dependencies between components at design time/compilation/run time

Question 19

Decentralized Software Control

Answer 19

Stair Sequence Diagram: Independent Objects (distributed control means better performance but outspread responsibility)

Question 20

Good System Design foresees ______________.

Answer 20

… fatal failures and deals with them.

Question 21

Virtual Proxy

Answer 21

Real object too expensive to create/download and doesn’t get accessed often.

Question 22

Protection Proxy

Answer 22

Access Control. Provides protection for the real object. Different actors with different viewing rights.

Question 23

Access Control

Answer 23

Associates list of pairs (actor; operation) with class: Player; play() with Match

Question 24

Software Control

Answer 24

implicit (rule-based & logic programming) + explicit (centralized & decentralized)