Philippe Kruchten, Grady Booch, Kurt Bittner, and Rich Reitman derived and refined a definition of architecture predicated on work by Mary Shaw and David Garlan (Shaw and Garlan 1996). Their definition is:
“Software architecture encompasses the set of significant decisions concerning the organization of a software system like the selection 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 typically common recurring themes when explaining architecture. He identifies these themes as:
“The highest-level breakdown of a system into its parts; the decisions which are Hard to change; you can find multiple architectures in a system; 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 creating a solution that’s well structured and meets all the technical and operational requirements. The architecture will be able to take into account and improve upon the normal quality attributes such as for example 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 information on individual components are design concerns, they are no architectural concerns but sometimes Design and Architecture concerns overlap.
Before starting the architecting of any software, there are some basic questions that we should strive to get answers for. They are as follows:
How the users of the machine will be interacting with the system?
How will the application form be deployed into production and managed?
What are the various non-functional requirements for the application, such as security, performance, concurrency, internationalization, and configuration?
How can the application form be designed to be flexible and maintainable as time passes?
Do you know the architectural trends that might impact your application now or after it has 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 the requirements that affect the basic structure of the application form. Good architecture reduces the business enterprise risks associated with building a technical solution while a good design is flexible enough in order 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 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 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 form as one learn more, so when one tests the design against real world requirements.
Keeping the above statement in mind, 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 investigate 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 using an incremental and iterative approach to refining their architecture. Focus on baseline architecture to achieve the big picture right, and then evolve candidate architectures as one iteratively ensure that you improve one’s architecture. Do not try to get it all right the first time-design just 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 obtain the big decisions right first, and then focus on the details. A standard pitfall is to dive in to the details too quickly and obtain the big decisions wrong by making incorrect assumptions, or by failing to evaluate your architecture effectively.
When testing your architecture, think about the following questions:
What were the primary assumptions which were made while architecting the machine?
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 spot to mitigate key risks?
In what ways is this architecture a noticable difference over the baseline or the final candidate architecture?
When getting started 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 main element factor to be considered is minimization of interaction points between independent feature sets to attain 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: An element or object should not know about internal details of other components or objects.
Don’t repeat yourself (DRY): The intent or implementation of any feature or functionality should be done at only one place. It will never be repeated in a few 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 form requirements are unclear, or when there is a possibility of the look evolving over time, one should avoid creating a large design effort prematurely.
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.
Establish 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 for example dependency analysis and static code analysis, during development
Not only development, also consider 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 one’s application.
Application Layers: While architecting and designing the system, one needs to carefully think about the various layers into that your application will be divided. There are several key considerations that need to be kept in mind while doing that:
Separate the regions of concern. Break the application into distinct features that overlap in functionality less than possible. The main benefit 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 one another.
Abstraction ought to be used to implement loose coupling between layers.
Do not mix different types of components in exactly the same logical layer. For example, the UI layer should not contain business processing components, but rather should contain components used to handle user input and process user requests.
Keep modern houses inside a layer or component.