How is software designed

The drawing is your modeling language and the resulting blueprint will be a model of your final design. You will continue to modify your drawings until you arrive at a design that meets all your requirements.

Only then should you start cutting boards or writing code. Again the benefit of designing your software using a modeling language is that you discover problems early and and fix them without refactoring your code. How do the different methodologies handle software design and modeling? Skip to main content. Home » Software Design and Modeling. This solution involves a lot of refactoring and can sometimes make it difficult to keep track of the bigger picture.

This tends to provide an initial solution that works for a limited set of requirements. An approach on the other extreme is to attempt to design as much as possible before implementation. This approach requires a fairly complete understanding of the requirements, but tends towards creating a solution that fits the needs of the entire system over the needs of each sub-component. There are many good choices between these two extremes.

Try to think of the overall big issues up front and create a design that addresses those problems. As you start to implement your design you may discover new problems that alter or add to your design and you may have to refactor your code to account for these changes, however these changes should be small. Once your application is up and running, as you get more and more users, you might run into performance issues. API calls might take a long time, servers might crash from being overloaded with requests, etc.

In order to solve these problems, you might read about integrating things like message queues or caches in order to improve performance.

Designing a system for scale can be incredibly challenging. It requires a deep understanding of the limitations of each component within the architecture, and a plan of action for how to mitigate stress on your architecture and continue to serve requests in high-traffic situations.

The need also the need to audit what's going on in your application. Large enterprise companies need to be able to perform audits in order to identify potential security issues, understand how users are using their applications, and have a log of everything that's ever happened. This can be challenging to implement, but common architectures end up looking event-based and build upon a wide range of software and system design concepts, principles, and practices like Event Storming, DDD, CQRS command query response segregation , and Event Sourcing.

Fork it on GitHub. Read the write-up. I'm Khalil. I enjoy teaching Advanced TypeScript best practices for large-scale applications and how to write flexible, maintainable software. If you read this far, tweet to the author to show them you care. Tweet a thanks. Learn to code for free. Get started. Forum Donate. Khalil Stemmler. Here's my roadmap for how to learn software design and architecture.

I've broken it down into two artifacts: the stack and the map. The Map While I think the stack is good to see the bigger picture of how everything works together, the map is a little bit more detailed and inspired by the web developer roadmap and as a result, I think it's more useful.

Stage 1: Clean code The very first step towards creating long-lasting software is figuring out how to write clean code. At the low-level, this manifests in a few design choices like: being consistent preferring meaningful variable, method and class names over writing comments ensuring code is indented and spaced properly ensuring all of the tests can run writing pure functions with no side effects not passing null Writing clean code is incredibly important.

Think of it like a game of jenga. Stage 2: Programming Paradigms Now that we're writing readable code that's easy to maintain, it would be a good idea to really understand the 3 major programming paradigms and the way they influence how we write code.

In Uncle Bob's book, " Clean Architecture ", he brings attention to the fact that: Object-Oriented Programming is the tool best suited for defining how we cross architectural boundaries with polymorhpism and plugins Functional programming is the tool we use to push data to the boundaries of our applications and Structured programming is the tool we use to write algorithms This implies that effective software uses a hybrid all 3 programming paradigms styles at different times.

If all you have is a hammer, everything seems like a nail. Resources For functional programming , check out: Professor Frisby's Mostly Adequate Guide to Functional Programming Domain Modeling Made Functional Stage 3: Object-Oriented Programming It's important to know how each of the paradigms work and how they urge you to structure the code within them, but with respect to architecture, Object-Oriented Programming is the clear tool for the job.

Why is that a huge deal? Stage 4: Design Principles At this point, you're understanding that Object-Oriented Programming is very useful for encapsulating rich domain models and solving the 3rd type of "Hard Software Problems"- Complex Domains. But OOP can introduce some design challenges. When should I use composition? When should I use inheritance?

When should I use an abstract class? Stage 5: Design Patterns Just about every problem in software has been categorized and solved already.

Creational Creational patterns are patterns that control how objects are created. Examples of creational patterns include: The Singleton pattern , for ensuring only a single instance of a class can exist The Abstract Factory pattern , for creating an instance of several families of classes The Prototype pattern , for starting out with an instance that is cloned from an existing one Structural Structural patterns are patterns that simplify how we define relationships between components.

Examples of structural design patterns include: The Adapter pattern , for creating an interface to enable classes that normally can't work together, to work together. The Bridge pattern , for splitting a class that should actually be one or more, into a set of classes that belong to a hierarchy, enabling the implementations to be developed independently of each other. The Decorator pattern , for adding responsibilities to objects dynamically. Behavioural Behavioural patterns are common patterns for facilitating elegant communication between objects.

Examples of behavioural patterns are: The Template pattern , for deferring the exact steps of an algorithm to a subclass.

The Mediator pattern , for defining the exact communication channels allowed between classes. The Observer pattern , for enabling classes to subscribe to something of interest, and to be notified when a change occurred.

Design pattern criticisms Design patterns are great and all, but sometimes they can an additional complexity to our designs. Here's what I'd recommend learning right off the bat: Component design principles: The Stable Abstraction Principle , The Stable Dependency Principle , and The Acyclic Dependency Principle, for how to organize components, their dependencies, when to couple them, and the implications of accidentally creating dependency cycles and relying on unstable components.

Policy vs. Whenever a software developer starts working on any type of new project, it is obvious that he would want to start scripting the code right away. Regardless of what his expertise is over the software are, if he builds software without laying out a plan for it, then he might be building a home without setting a strong foundation.

Well, no matter how strong the building process and use of resources are, the house is going to collapse, similarly, without a foundational layout, the software is also going to crash. Nobody really wills to let the effort go in vain, just out of a silly mistake of not setting a plan for it, right? Well, that is where software design comes into play, a mechanism that allows critical software processes to be simplified in a certain manner.

It is obvious that while talking about software design, a question pops up, what is this software design after all? Well, the answer is not as critical as you might think. Software design is basically a mechanism of preparing a plan, a layout for structuring the code of your software application.

It is as simple as that to define, but is this that easy to perform? Well, that is a whole different scenario but if you are to perform software design for your new software project then it is a necessity to know its importance, otherwise, you might just miss the crisp of it.

Software design is a multi-stage concept. The software itself is a multi-layer, multi-dimensional spectrum, and its design has multiple intermediate steps, therefore; different types of software level design. Architectural Design: Architectural design is the first step in software-level design. This involves the construction of a software application structure in order to have the correct interconnection of each element of code according to the required function.

High-level Design: This is the second step in software-level design. In this step, the designer splits the theoretical concepts, into multiple entities and ensures their functions are inter-related to get an optimum result.

This module identifies a modular structure of different entities and creates a design to inter-connect all modules for a specific output. Detailed Design: This is the third and last step of the software-level design. It involves the compilation of all modular outputs and arrangement or rearrangement o functional modules for the final outcome.

This level of software design determines more of a logical structure out of constructed modules. The software outcome accomplishment part is the motive of the detailed design level of software design. Why Is It So Important? As mentioned earlier, software design is the process of setting a foundation for constructing your software structure code.