Software Architecture and Design – Goals, Principles plus some Key Considerations

Philippe Kruchten, Grady Booch, Kurt Bittner, and Rich Reitman derived and refined a definition of architecture based on work by Mary Shaw and David Garlan (Shaw and Garlan 1996). Their definition is:

“Software architecture encompasses the set of significant decisions about the organization of a software system like the selection of the structural elements and their interfaces where the system is made up; behavior as specified in collaboration the type of elements; composition of these structural and behavioral elements into larger subsystems; and an architectural style that guides this organization. Software architecture also involves functionality, usability, resilience, performance, reuse, comprehensibility, economic and technology constraints, tradeoffs and aesthetic concerns.”

In Patterns of Enterprise Application Architecture, Martin Fowler outlines some typically common recurring themes when explaining architecture. He identifies these themes as:

“The highest-level breakdown of a system into its parts; the decisions that are Hard to change; you can find multiple architectures in something; what is architecturally Significant can change over a system’s lifetime; and, ultimately, architecture boils Down to regardless of the important stuff is.”

Software application architecture may be the process of defining and coming up with a solution that is well structured and meets all the technical and operational requirements. The architecture will be able to take into account and improve upon the common quality attributes such as performance, security, and manageability.

The main focus of the program architecture is the way the major elements and components within an application are employed by, or connect to, other major elements and components within the application form. Selecting data structures and algorithms or the implementation details of individual components are design concerns, they’re not an architectural concerns but sometimes Design and Architecture concerns overlap.

Prior to starting the architecting of any software, there are some basic questions that people should strive to get answers for. modern houses are as follows:

How the users of the system will be interacting with the machine?

How will the application be deployed into production and managed?

Do you know the various non-functional requirements for the application form, such as security, performance, concurrency, internationalization, and configuration?

How can the application form be designed to be flexible and maintainable over time?

What are the architectural trends that may impact your application now or after it’s been deployed?

Goals of Software Architecture

Building the bridge between business requirements and technical requirements may be the main goal of any software architecture. The goal of architecture is to identify the requirements that affect the basic structure of the application. Good architecture reduces the business risks associated with creating a technical solution while an excellent design is flexible enough in order to handle the changes that will occur over time in hardware and software technology, in addition to in user scenarios and requirements. An architect must consider the overall aftereffect of design decisions, the inherent tradeoffs between quality attributes (such as for example performance and security), and the tradeoffs necessary to address user, system, and business requirements.

Principles of Software Architecture

The essential assumption of any architecture should be the belief that the look will evolve as time passes and that one cannot know everything one have to know up front. The design will generally have to evolve through the implementation stages of the application as one learn more, so when one tests the look against real world requirements.

Keeping the above statement at heart, let’s try to list down some of the Architectural principles:

The system should be created to change rather than building to last.

Model the architecture to analyze and reduce risk.

Use models and visualizations as a communication and collaboration tool.

The key engineering decisions ought to be identified and acted upon upfront.

Architects should consider utilizing an incremental and iterative method of refining their architecture. Start with baseline architecture to get the big picture right, and then evolve candidate architectures as you iteratively test and improve one’s architecture. Usually do not try to get it all right the first time-design as much as you can in order to start testing the design against requirements and assumptions. Iteratively add details to the look over multiple passes to make certain that you get the big decisions right first, and focus on the details. A common pitfall is to dive in to the details too quickly and get the big decisions wrong by making incorrect assumptions, or by failing to evaluate your architecture effectively.

When testing your architecture, consider the following questions:

What were the primary assumptions that were made while architecting the machine?

What are the requirements both explicit and implicit this architecture is satisfying?

What are the key risks with this architectural approach?

What countermeasures are in place to mitigate key risks?

In what ways is this architecture an improvement over the baseline or the final candidate architecture?

Design Principles

When getting started off with Software design, one should take into account the proven principles and the principles that adheres to minimizes costs and maintenance requirements, and promotes usability and extensibility. The main element principles of any Software Design are:

Separation of concerns: The key factor to be considered is minimization of interaction points between independent feature sets to accomplish high cohesion and low coupling.

Single Responsibility principle: Each component or module ought to be independent in itself and in charge of just a specific feature or functionality.

Principle of Least Knowledge: A component or object should not find out about internal information on other components or objects.

Don’t repeat yourself (DRY): The intent or implementation of any feature or functionality should be done of them costing only one place. It should never be repeated in a few other component or module

Minimize upfront design: This principle is also sometimes known as YAGNI (“You ain’t gonna require it”). Design only what’s necessary. Specifically for agile development, you can avoid big design upfront (BDUF). If the application form requirements are unclear, or if there is a possibility of the design evolving over time, you need to avoid making a large design effort prematurely.

Design Practices

Keep design patterns consistent within each layer.

Do not duplicate functionality within an application.

Prefer composition to inheritance. When possible, use composition over inheritance when reusing functionality because inheritance escalates the dependency between parent and child classes, thereby limiting the reuse of child classes. This also reduces the inheritance hierarchies, which can become very difficult to deal with.

Set up a coding style and naming convention for development.

Maintain system quality using automated QA techniques during development. Use unit testing along with other automated Quality Analysis techniques, such as dependency analysis and static code analysis, during development

Not only development, also think about the operation of your application. Determine what metrics and operational data are required by the IT infrastructure to guarantee the efficient deployment and operation of your application.

Application Layers: While architecting and designing the system, one needs to carefully think about the various layers into which the application will be divided. There are some key considerations that need to be considered while doing that:

Separate the areas of concern. Break the application into distinct features that overlap in functionality as little as possible. The main benefit of this approach is a feature or functionality can be optimized independently of other features or functionality

Be explicit about how exactly layers communicate with each other.

Abstraction ought to be used to implement loose coupling between layers.

Do not mix various kinds of components in the same logical layer. For instance, the UI layer should not contain business processing components, but instead should contain components used to handle user input and process user requests.

Keep carefully the data format consistent inside a layer or component.