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 like the selection of the structural elements and their interfaces by which the system is composed; 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 whatever the important stuff is.”
Software application architecture is the process of defining and creating a solution that’s well structured and meets all the technical and operational requirements. The architecture should 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 Software architecture is how 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 information on individual components are design concerns, they are no architectural concerns but sometimes Design and Architecture concerns overlap.
Prior to starting the architecting of any software, there are several basic questions that people 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 security, performance, concurrency, internationalization, and configuration?
How can the application form be made to be flexible and maintainable as time passes?
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 is 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 in order to handle the changes that may occur as time passes in hardware and software technology, as well as in user scenarios and requirements. An architect must consider the overall aftereffect 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 look will evolve over time and that certain cannot know everything one need 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 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 built to change instead of 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 should be identified and applied upfront.
Architects should consider using an incremental and iterative method of refining their architecture. Focus on baseline architecture to have the big picture right, and 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 to be able to 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 then focus on the details. A standard 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 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 particular 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 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 main element 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 should 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 details of 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. Especially for agile development, you can avoid big design upfront (BDUF). If the application requirements are unclear, or if there is a possibility of the look evolving over time, one should avoid making 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 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 handle.
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. Know what metrics and operational data are required by the IT infrastructure to guarantee the efficient deployment and operation of your application.
fontaneria Valencia : While architecting and designing the system, one needs to carefully consider the various layers into which the application will be divided. There are a few key considerations that need to be considered while doing that:
Separate the areas of concern. Break your application into distinct features that overlap in functionality less than possible. The advantage of this approach is a feature or functionality can be optimized independently of other features or functionality
Be explicit about how 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 rather should contain components used to take care of user input and process user requests.
Keep carefully the data format consistent within a layer or component.
