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 selection of the structural elements and their interfaces where the system is composed; 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 common recurring themes when explaining architecture He identifies these themes as "The highest-level breakdown of something into its parts; the decisions that are Hard to change; you can find multiple architectures in something; what is architecturally Significant can transform over a system's lifetime; and, in the end, 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's well structured and meets all the technical and operational requirements The architecture will be able to consider and improve upon the normal quality attributes such as for example performance, security, and manageability https//hackmdio/faVVCq1WTnSU4_a-tOjx4g/H1zuGzCGA of the Software architecture is how the major elements and components in a 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 a few 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 Do you know the various non-functional requirements for the application, such as for example security, performance, concurrency, internationalization, and configuration How can the application form be made to be flexible and maintainable over time Do you know the architectural trends that may impact your application now or after it has been deployed Goals of Software Architecture Building the bridge between business requirements and technical requirements is the main goal of any software architecture The goal of architecture is to identify the requirements that affect the essential structure of the application Good architecture reduces the business risks associated with building a technical solution while an excellent design is flexible enough in order to handle the changes that may occur over time in hardware and software technology, as well as 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 ought to be the belief that the design will evolve over time and that one cannot know everything one need to know up front The design will generally need to evolve during the implementation stages of the application form as one learn more, and as one tests the look against real world requirements Keeping the above statement in mind, let's make an effort to list down a number 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 utilizing an incremental and iterative approach to refining their architecture Focus on baseline architecture to get the big picture right, and then evolve candidate architectures as you iteratively ensure that you improve one's architecture Do not try to get it all right the first time-design as much as you can so that you can start testing the design against requirements and assumptions Iteratively add details to the look over multiple passes to ensure that you obtain the big decisions right first, and focus on the details A common pitfall is to dive into 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, consider the following questions What were the main assumptions which were made while architecting the machine What are the requirements both explicit and implicit this architecture is satisfying Do you know the key risks with this architectural approach What countermeasures are in spot to mitigate key risks In what ways is this architecture an improvement over the baseline or the last candidate architecture Design Principles When getting started off with Software design, one should keep 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 considered 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 responsible for only a specific feature or functionality Principle of Least Knowledge An element 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 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 can be sometimes known as YAGNI "You ain't gonna need it" Design only what's necessary Especially for agile development, you can avoid big design upfront BDUF If the application requirements are unclear, or if you have a possibility of the look evolving over time, one should 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 When possible, use composition over inheritance when reusing functionality because inheritance escalates the dependency between parent and ***** classes, thereby limiting the reuse of ***** classes This also reduces the inheritance hierarchies, which can become very difficult to handle Set up a coding style and naming convention for development Maintain system quality using automated QA techniques during development Use unit testing and 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 your application Application Layers While architecting and designing the system, one needs to carefully consider the various layers into that your application will be divided There are several key considerations that require 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 advantage of this approach is a feature or functionality could be optimized independently of other features or functionality Be explicit about how exactly layers communicate with one another Abstraction ought to be used to implement loose coupling between layers Do not mix various kinds of components in exactly the same logical layer For instance, the UI layer should not contain business processing components, but rather should contain components used to handle user input and process user requests Keep the data format consistent within a layer or component