Software Engineering Reuse & Patterns

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Questions and Answers

What role does the Model play in the Model-View-Controller architecture?

It handles notifications and updates from external sources.

It manages user interactions and input processing.

It holds all the data, state, and application logic. (correct)

It provides a presentation of the data to the user.

Which component in the Notification/Implicit-Invocation architecture is responsible for notifying subscribers of events?

Service Consumer

Observer/Subscriber

Controller

Subject/Publisher (correct)

How do consumers utilize services in a service-oriented architecture?

By invoking all services simultaneously.

By developing new services for each process.

By combining services to fulfill business processes. (correct)

By relying solely on individual services without any integration.

In the Model-View-Controller framework, how does the View obtain data to present to the user?

By accessing the Model directly. Signup and view all the answers

What is an example of a system that utilizes a Notification/Implicit-Invocation architecture?

RSS feed for news updates. Signup and view all the answers

What is one major aspiration of software engineering regarding reuse?

To avoid duplication of effort. Signup and view all the answers

Why is reuse in software desirable?

It increases reliability by using proven solutions. Signup and view all the answers

What do architectural patterns provide to developers?

A common language for understanding solutions. Signup and view all the answers

What is a characteristic of a good pattern in software engineering?

It contains a proven solution for a specific context. Signup and view all the answers

Studying software patterns is beneficial because it allows:

Reuse of experiences accumulated from previous work. Signup and view all the answers

How do architectural patterns affect software quality?

They provide proven solutions that improve quality. Signup and view all the answers

What advantage does using existing solutions offer to software developers?

It speeds up the development process. Signup and view all the answers

What are the two main categories of software architectural patterns?

Architectural structure patterns and architectural communication patterns Signup and view all the answers

Which of the following is NOT listed as a commonly employed architectural style?

Database-oriented Signup and view all the answers

In client-server architecture, what role does the server play?

It processes requests and provides services to clients. Signup and view all the answers

What does a call-return architecture primarily involve?

Procedure calls and waiting for return. Signup and view all the answers

Which architectural style is characterized by dynamic communication among distributed components?

Architectural communication patterns Signup and view all the answers

Which pair of architectural styles shows the most overlap?

Peer-to-Peer and Client-Server Signup and view all the answers

How does a server in a client-server architecture respond to client requests?

By processing received requests and returning responses. Signup and view all the answers

Which of the following best describes a service-oriented architecture?

Utilizes independent services that communicate over a network. Signup and view all the answers

Which architecture would best suit situations requiring asynchronous communication between components?

Service-Oriented Signup and view all the answers

What is the primary focus of architectural structure patterns?

Static structural design of architecture Signup and view all the answers

What is one of the main reasons for decomposing systems in software architecture?

To tackle complexity by 'divide-and-conquer' Signup and view all the answers

Which type of software pattern focuses on the overall structure and interconnections within a system?

Architectural Patterns Signup and view all the answers

What does 'programming-in-the-large' refer to in software architecture?

The high-level structure and organization of the system Signup and view all the answers

Which pattern type is NOT a part of software patterns listed in the content?

Coding Practices Patterns Signup and view all the answers

What is the benefit of separating unrelated parts in software architecture?

Support for flexibility and future evolution Signup and view all the answers

Which of the following best describes the term 'interfaces' in the context of software architecture?

The visible properties and relationships among components Signup and view all the answers

How can existing parts of a software system benefit the development process?

By allowing for reuse and reducing redundancy Signup and view all the answers

What principle emphasizes the importance of external views and interconnections in software systems?

Separation of concerns Signup and view all the answers

Which pattern type focuses specifically on the responsibilities within a software architecture?

Assigning Responsibilities Patterns Signup and view all the answers

What is considered the highest abstraction level in the product line hierarchy?

System or Product Signup and view all the answers

Which type of requirements must architecture fulfill according to the content?

Both functional and non-functional requirements Signup and view all the answers

What is the goal of the Twin-peaks model mentioned in the content?

To develop requirements and architecture concurrently Signup and view all the answers

In architectural design, multiple architectures can meet functional requirements, but what differentiates them?

Their non-functional requirements Signup and view all the answers

Which of the following is a non-functional requirement related to software architecture?

Performance Signup and view all the answers

How does Skype's architecture improve reliability based on non-functional requirements?

By moving super nodes to its own servers Signup and view all the answers

What is one important software quality attribute when developing software architecture?

Maintainability Signup and view all the answers

What describes the earlier node structure of Skype's architecture?

All nodes were equivalent before changes were made Signup and view all the answers

Which aspect is considered when assessing non-functional requirements in software architecture?

Security Signup and view all the answers

Which of the following describes the relationship between functional and non-functional requirements in software architecture?

Not all non-functional requirements are equally important Signup and view all the answers

Study Notes

Lecture Objectives

Introduce the concept of Reuse in Software Engineering
Introduce the concepts of Architectural Diagrams & Patterns
Discuss why architectural patterns are important and what advantages they provide
Discuss 10 selected architectural patterns

Reuse in Software Engineering

A major aspiration of software engineering is reuse, taking existing solutions and adapting them.
Reuse is desirable because it avoids duplication of effort, saves resources, and promotes reliability.
It speeds up development and spreads good practices.

Introduction to Patterns

A pattern outlines a reusable solution to a recurring problem in a particular context.
Many software patterns are systematically documented for developers.
A good pattern provides a solution proven to effectively solve the problem in the indicated context.
Studying patterns is an effective way to learn from the experience of others.

Motivation for Patterns

Patterns provide a common language between developers.
They improve software quality and reduce development time, based on object-oriented design principles and heuristics.

Software Patterns

Reuse exists at several levels.
Software patterns include Requirements Patterns, Analysis Patterns, Architectural Patterns, Assigning responsibilities patterns, Design Patterns, and Idioms.

Software Architectural Design

Software architecture is the structure of a program or computing system, including elements, their properties and relationships.
Distinguishes overall structure from internal details.
Components and their interconnections are referred to as programming-in-the-large, while detailed design of individual components is programming-in-the-small.
Can be described at different levels of detail, ranging from decomposition into subsystems to modules and components.

Why Decompose Systems

Tackle complexity using the "divide-and-conquer" method.
See if parts already exist and can be reused.
Support flexibility and future evolution by decoupling unrelated parts.

Software Architectural Design (Levels of Detail)

Details range from the highest abstraction level (e.g., product line) to the lowest level (e.g., source code).

Software Architectural Design & Requirements

Architecture must fulfill both functional (what the software does) and nonfunctional (how well it does it) requirements.
The Twin-peaks model (Nuseibeh, 2001) concurrently develops requirements and architecture.

Software Architectural Design & Functional vs. Non-functional Requirements

Multiple architectures can meet functional needs but not all are equally effective for non-functional requirements.
Importance of considering non-functional requirements like performance, security, and maintainability when designing the software architecture.

Software Architectural Design & Non-functional Requirements (Example: Skype)

Skype's architecture is impacted by a non-functional requirement of reliability.
Skype initially used distributed peer-to-peer architecture, but later adopted a mixed P2P and client-server model to enhance reliability with central server supervision for the nodes responsible for call routing.

Software Architectural Design: Architectural Patterns/Styles

Architectural patterns (styles) are recurring architectures in various software applications (e.g. client/server, layered).
Categories exist in architectural structure patterns (addressing static structure) and architectural communication patterns (addressing dynamic communication).

Commonly Employed Architectural Styles

Client-Server
Data-Centred
Call-Return (Procedure Call)
Layered/Tiered
Peer-to-Peer
Data-flow (Pipes & Filters)
Data-Centred (Repository/Black-board)
Independent Components
Service-Oriented
Notification/Publish-Subscribe
Model-View-Controller

Client-Server Architecture

A Server performs a service for clients.
Server waits for requests, processes them and responds.

Call-Return Architecture

A component calls another component and waits for the call to return.

Layered (Tiered) Architecture

System structured as stacked layers.
Lower layers provide services for upper layers.
Examples: Java programs, OSI, TCP/IP models.

Peer-to-Peer Architecture

All components are both clients and servers.
Components can request services from each other.

Data-Flow (Pipes & Filters) Architecture

Components process data in a stream.
Unidirectional communication, using pipes and filters.

Data-Centred (Repository/Black-board) Architecture

Centralized data store.
Data structure stable.
Many clients can access and modify data.
Potential of data backup.

Independent Components Architecture

Components execute concurrently.
Decoupled.
Communication via messages to exchange data and coordinate operations.

Service-Oriented Architecture

Two kinds of components: consumers and providers.
Providers offer services; consumers use these.

Subscribers register with publishers to receive updates.
Publishers notify subscribers of relevant events.

Model-View-Controller Architecture

Model: Data, state, application logic.
View: Presentation of the model to the user.
Controller: Handles user input/interactions.

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Description

This quiz explores the key concepts of reuse in software engineering and the significance of architectural patterns. It highlights the advantages of using established solutions to recurring problems and discusses 10 selected architectural patterns. Enhance your understanding of how these patterns improve development efficiency and reliability.