Question 7 Flashcards
Architectural styles
Client server - server requests from client –processes – responds
E.g. Web browser to web server
Service oriented- consumers & providers
E.g. Different divisions of an organisation whose system use same set of services such as payroll
Layered- LAMP stack series of layers stacked
Web browser
Web server
Php
MySQL
Disadvantage: layers can only talk to layers above or below
Call return- caller makes call to another component and awaits reply
Peer to peer- similar to client server except all components are both clients and servers and any component can request services from any other component.
Independent components- execute concurrently communicate via messages. Decoupled as far as possible.
Data flow - components/ sub programs that process a stream of data and pass the results on to other components for further processing.
Notification - observers and subjects. when event happens observers are notified
Data centred - centralised store of data such as a database can be updated, queried, updated (crud)
What are architectural views
We use architectural views to emphasise issues that matter to particular groups of stakeholders
Architectural views
Logical view
Describes the main functional elements and how they interact and assumes that these correspond to subsystems that can be allocated to teams of developers.
Architectural views
Process view
Describes the independent processes executing at runtime and the communication between them regarding the processes as components and the communication as taking place via connectors.
Architectural view
Deployment view
Is the physical view describing how the system will be deployed to an operating environment, the physical computers and networks on which the system will run. It is important to us because deployment decisions will have a major impact on quality attributes.
What is a framework
Segments of architecture and code that can be reused/ adapted to develop new systems
What are design patterns?
Reusable solutions to design problems
Adapter pattern
MVC - model view controller
Observer pattern
Adapter pattern
Can solve a problem that crops up time and time again
Can make two incompatible interfaces, compatible
MVC model view controller
Often used in applications that have graphical user interfaces
E.g. All Clocks can have the same mechanism but have a completely different face (interface)
You can choose to have a different kind of user interface without having to change the part of the program that does the processing.
Observer pattern
Many online forums allow you to subscribe and receive an email notification when a new forum post is made.
Singleton pattern
The singleton pattern ensures that a class only has one instance and to provide a global point of access to it E.g. Hotel chain
