Agile Model in Software Engineering

What is an Agile Model?

The Agile Model is an incremental and iterative process of software development. It defines each iteration’s number, duration, and scope in advance. Every iteration is considered a short “frame” in the Agile process model, which mostly lasts from two to four weeks.

Agile Model divides tasks into time boxes to provide specific functionality for the release. Each build is incremental in terms of functionality, with the final build containing all the attributes. The division of the entire project into small parts helps minimize the project risk and the overall project delivery time.

Agile Model

What are the important Agile Model Manifestos?

Here is the essential manifesto of the Agile Model:

  • Individuals and interactions are given priority over processes and tools.
  • Adaptive, empowered, self-organizing team.
  • Focuses on working software rather than comprehensive documentation.
  • Agile Model in software engineering aims to deliver complete customer satisfaction by rapidly delivering valuable software.
  • Welcome changes in requirements, even late in the development phase.
  • Daily co-operation between businesspeople and developers.
  • Priority is customer collaboration over contract negotiation.
  • It enables you to satisfy customers through early and frequent delivery.
  • A strong emphasis is placed on face-to-face communication.
  • Developing working software is the primary indicator of progress.
  • Promote sustainable development pace.
  • A continuous focus is placed on technical excellence and sound design.
  • An improvement review is conducted regularly by the team.

Phases of Agile Model

Here are the different phases of Agile:

Phases of Agile Model

Here are the important stages involved in the Agile Model process in the SDLC life cycle:

  • Requirements Gathering: In this Agile model phase, you must define the requirements. The business opportunities and the time and effort required for the project should also be discussed. By analyzing this information, you can determine a system’s economic and technical feasibility.
  • Design the Requirements: Following the feasibility study, you can work with stakeholders to define requirements. Using the UFD diagram or high-level UML diagram, you can determine how the new system will be incorporated into your existing software system.
  • Develop/Iteration: The real work begins at this stage after the software development team defines and designs the requirements. Product, design, and development teams start working, and the product will undergo different stages of improvement using simple and minimal functionality.
  • Test: This phase of the Agile Model involves the testing team. For example, the Quality Assurance team checks the system’s performance and reports bugs during this phase.
  • Deployment: In this phase, the initial product is released to the user.
  • Feedback: After releasing the product, the last step of the Agile Model is feedback. In this phase, the team receives feedback about the product and works on correcting bugs based on the received feedback.

Compared to Waterfall, Agile cycles are short. There may be many such cycles in a project. The phases are repeated until the product is delivered.

Types of Agile

Here are some important Agile Types:

Scrum: This agile method focuses primarily on managing tasks in team-based development conditions. In the Scrum Agile model, the team should strictly follow a work plan for each Sprint. Moreover, people involved in this type of project have predefined roles.

Crystal: Using Crystal methodology is one of the most straightforward and most flexible approaches to developing software, recognizing that each project has unique characteristics. Therefore, policies and practices need to be tailored to suit them.

Crystal methodologies are categorized as below:

  • CLEAR: User for small and low critical efforts.
  • ORANGE: User for moderately larger and critical projects.
  • ORANGE WEB: Typically, electronic business

Dynamic Software Development Method (DSDM): This Rapid Application Development (RAD) approach involves active user involvement, and the teams are empowered to make decisions with the goal of frequent product delivery.

Feature Driven Development (FDD): This Agile method focuses on “designing & building” features. It is divided into several short phases of work that must be completed for each feature separately. It includes domain walkthrough, design inspection, code inspection, etc.

Lean Software Development: This methodology is based on the principle of “Just-In-Time Production.” It helps to increase the speed of software development and decrease costs.

As a result of a lean development model, waste is eliminated, learning is amplified, early delivery is achieved, and integrity is built.

Extreme Programming (XP): Extreme Programming is a useful Agile model when there are constantly changing requirements or demands from clients. It is also used when there is no sure about the system’s functionality.

When to use the Agile Model?

Here are the common scenarios where the Agile method is used:

  • It is used when there are frequent changes that need to be implemented.
  • Low-regulatory-requirement projects
  • Projects with not very strict existing process
  • Projects where the product owner is highly accessible
  • Projects with flexible timelines and budget

Advantages of the Agile Model

Here are some common pros/benefits of the Agile Model:

  • Communication with clients is on a one-on-one basis.
  • Provides a very realistic approach to software development
  • Agile Model in software engineering enables you to draft efficient designs and meet the company’s needs.
  • Updated versions of functioning software are released every week.
  • It delivers early partial working solutions.
  • Changes are acceptable at any time.
  • You can reduce the overall development time by utilizing this Agile Model.
  • It allows concurrent development and delivery within an overall planned context.
  • The final product is developed and available for use within a few weeks.

Disadvantages of Agile Model

Here are some common cons/drawbacks of the Agile Model:

  • There is a higher risk of sustainability, maintainability, and extensibility.
  • In some corporations, self-organization and intensive collaboration may not be compatible with their corporate culture.
  • Documentation and design are not given much attention.
  • Without clear information from the customer, the development team can be misled.
  • Not a suitable method for handling complex dependencies.

Agile Model Vs. Waterfall Model

Agile and Waterfall models are two different methods for the software development process. Despite their differences in approach, both methodologies can be used at times, depending upon the project and the requirements.

Agile Model Waterfall Model
Agile methodologies propose incremental and iterative approaches to software design Software development flows sequentially from start point to end point.
The Agile Model in software engineering is broken into individual models that designers work on The design process is not broken into individual models
The customer has early and frequent opportunities to look at the product and make decisions and changes. The customer can only see the product at the end of the project.
The Agile Model is considered unstructured compared to the waterfall model Waterfall models are more secure because they are plan oriented
Small projects can be implemented very quickly. For large projects, it isn’t easy to estimate the development time. All sorts of the project can be estimated and completed.
Test plan is reviewed after each Sprint The test plan is hardly discussed during the test phase.

Please refer to this link for a detailed comparison between Agile and Waterfall model.

Summary

  • The Agile Model is an incremental and iterative process of software development.
  • It focuses on working software rather than comprehensive documentation.
  • Agile model is divided into various stages like 1) Requirements Gathering, 2) Design the Requirements, 3) Develop/Iteration, 4) Test, 5) Deployment 6) Feedback.
  • Various types of Agile types are: 1) Scrum, 2) Crystal, 3) Dynamic Software Development Method (DSDM): 4) Feature Driven Development (FDD), 5) Lean Software Development 6) Extreme Programming (XP).
  • The agile model is used when frequent changes need to be implemented.
  • It provides a very realistic approach to software development
  • This model has a greater risk of sustainability, maintainability, and extensibility.
  • Agile methodologies in Software Testing adopt incremental and iterative approaches to software design, whereas software development flows sequentially from the starting point to the endpoint.