Architecture patterns

Question 1

aims of software patterns

Answer 1

enhance reusability of OO code

Question 2

benefits of design patterns

Answer 2

capture expertise and make it accessible to non-experts in an encapsulated design pattern
help communication amongst devs 
makes usuability easier
facilitate design modifications
improve design documentation

Question 3

architectural model

Answer 3

artefact documenting some or all of the architectural design decisions about a system

Question 4

architecture visualization

Answer 4

depicts some or all of design decisions to a stakeholder

Question 5

architecture view

Answer 5

subset of related architectural design decisions

Question 6

when is MVC pattern used

Answer 6

when there are multiple ways to view and interact with the data
when the future requirements for interaction and presentation of data are unknown

Question 7

how does MVC work

Answer 7

separates presentation and interaction of data
Model - manages systems data ans associated operations on that data
view - manages how the data appears to the user
controller manages the user interaction and passes these interaction to the view and the model

Question 8

pros of mvc

Answer 8

allows data to change independently of its representation

supports presentation of the same data in different ways with changes made in one representation shown in all of them

Question 9

cons of mvc

Answer 9

can involve additional code and code complexity

Question 10

when is layered architecture pattern used

Answer 10

when building new facilities on top of existing systems

development spread across several teams

Question 11

how does layered architecture work

Answer 11

organizes system into layers with related functionality associated with each layer

Question 12

pros of layered arch

Answer 12

servers can be distributed across a network and servers can be added/removed with minimal disruption

Question 13

cons of layered arch

Answer 13

each service is a single point of failure - server failure
performance can be unpredictable because it depends on the network and the system
server management issues

Question 14

when is pipe and filter pattern used

Answer 14

data processing applications where inputs are processed in separate stages to generate related outputs

Question 15

how does pipe and filter pattern work

Answer 15

processing of the data in a system is organized so that each processing component (filter) carries out one type of data transformation. Data flows via pipe into component for processing

Question 16

pros of pipe and filter pattern

Answer 16

easy to understand and supports transformation reuse
matches structure of many business processes
evolution by adding filters/transformation
implemented sequentially or concurrent

Question 17

cons of pipe and filter pattern

Answer 17

format for data transfer has to be agreed upon between communicating transformations
input parsing and unparsing - overhead, difficult to reuse things

Question 18

key aim of design patterns

Answer 18

minimize coupling (degree to which communication takes place between modules) and increase cohesion (degree to which communication takes place within module)

Question 19

problems because of a design with high coupling

Answer 19

changes in related classes force local changes
harder to understand inisolation
harer to reuse

Question 20

Examples of non-functional requirements

Answer 20

performance
security
safety
availability
maintainability

Question 21

when to use repository pattern

Answer 21

when you have system in which large volume of information is generated that has to be stored for a long time
data-driven systems where the inclusion of data in the repository triggers an action or tool

Question 22

how does the repository pattern work

Answer 22

all data in a system is managed in a central repository that is accessible to all system components
components only interact through

Question 23

pros of repository system

Answer 23

components can be independent

all data managed consistantly

Question 24

cons of repos system

Answer 24

single point of failure - one issue can affect the whole system
efficiencies in organzainisng all communications through the repo
distributing repo across various computers may be difficult