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 group of significant decisions about the organization of a software system including the collection of the structural elements and their interfaces by which the system is made up; behavior as specified in collaboration among those elements; composition of the 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 common recurring themes when explaining architecture. He identifies these themes as:

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

Software application architecture is the process of defining and coming up with a solution that’s well structured and meets all the technical and operational requirements. The architecture should be able to consider 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 used by, or connect to, other major elements and components within the application. Selecting data structures and algorithms or the implementation details of individual components are design concerns, they are not an architectural concerns but sometimes Design and Architecture concerns overlap.

Prior to starting the architecting of any software, there are several basic questions that we should make an effort to get answers for. They’re as follows:

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

How will the application form be deployed into production and managed?

What are the various non-functional requirements for the application form, such as security, performance, concurrency, internationalization, and configuration?

How can the application be made to be flexible and maintainable as time passes?

Do you know 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 definitive goal of any software architecture. The goal of architecture is to identify certain 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 to handle the changes that may occur as time passes in hardware and software technology, in addition to in user scenarios and requirements. An architect must think about the overall effect 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 basic assumption of any architecture should be the belief that the design will evolve as time passes and that certain cannot know everything one have to know up front. The look will generally need to evolve during 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 make an effort to list down some of the Architectural principles:

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

Model the architecture to investigate and reduce risk.

Use models and visualizations as a communication and collaboration tool.

The key engineering decisions should be identified and applied upfront.

Architects should consider using an incremental and iterative method of refining their architecture. Start with baseline architecture to find the big picture right, and evolve candidate architectures as one iteratively test and improve one’s architecture. Do not try to get it fine the first time-design as much as you can as a way to start testing the look against requirements and assumptions. Iteratively add details to the design over multiple passes to make sure that you get the big decisions right first, and focus on the details. A standard pitfall is to dive into the details too quickly and obtain the big decisions wrong by making incorrect assumptions, or by failing woefully to evaluate your architecture effectively.

When testing your architecture, consider the following questions:

What were the main assumptions which were made while architecting the system?

Do you know 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 a noticable difference over the baseline or the last candidate architecture?

Design Principles

When getting started with Software design, one should bear in mind the proven principles and the principles that adheres to minimizes costs and maintenance requirements, and promotes usability and extensibility. The key principles of any Software Design are:

Separation of concerns: The main element factor to be kept in mind is minimization of interaction points between independent feature sets to achieve 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 know about internal information on other components or objects.

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

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

Design Practices

Keep design patterns consistent within each layer.

Do not duplicate functionality in a application.

Prefer composition to inheritance. If possible, use composition over inheritance when reusing functionality because inheritance increases the dependency between parent and child classes, thereby limiting the reuse of child classes. read more reduces the inheritance hierarchies, that may 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 needed by the IT infrastructure to ensure 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 advantage of this approach is that a feature or functionality can be optimized independently of other features or functionality

Be explicit about how layers communicate with each other.

Abstraction should 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 take care of user input and process user requests.

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