When developing software, creating understandable, readable, and testable code is not just a nice thing to do, but it is a necessity. This is because having clean code that could be reviewed and worked on by other developers is an essential part of the development process. When it comes to object oriented programming languages, there are a few design principles that help you avoid design smells and messy code. These principles are known as the SOLID principles. These principles were originally introduced by Robert J. Martin back in 2000. SOLID is an acronym for five object oriented design principles. These principles are:

1. Single Responsibility Principle – A class should have one and only one reason to change, meaning that a class should have only one job. This principle helps keep code consistent and it makes version control easier.
2. Open Closed Principle – Objects or entities should be open for extension but closed for modification. This means that we should only add new functionality to the code, but not modify existing code. This is usually done through abstraction. This principle helps avoid creating bugs in the code.
3. Liskov Substitution Principle – Let q(x) be a property provable about objects of x of type T. Then q(y) should be provable for objects y of type S where S is a subtype of T. This means that subclasses can substitute their base class. This is expected because subclasses should inherit everything from their parent class. They just extend the parent class, they never narrow it down. This principle also helps us avoid bugs.
4. Interface Segregation Principle – A client should never be forced to implement an interface that it doesn’t use, or clients shouldn’t be forced to depend on methods they do not use. This principle helps keeps the code flexible and extendable.
5. Dependency Inversion Principle – Entities must depend on abstractions, not on concretions. It states that the high-level module must not depend on the low-level module, but they should depend on abstractions. This means that dependencies should be reorganized to depend on abstract classes rather than concrete classes. Doing so would help keep our class open for extension. This principle helps us stay organized as well as help implement the Open Closed Principle.

These design principles act as a framework that helps developers write cleaner, more legible code that allows for easier maintenance and easier collaboration. The SOLID principles should always be followed because they are best practices, and they help developers avoid design smells in their code, which will in turn help avoid technical debt.

https://www.digitalocean.com/community/conceptual_articles/s-o-l-i-d-the-first-five-principles-of-object-oriented-design#single-responsibility-principle

https://www.freecodecamp.org/news/solid-principles-explained-in-plain-english/

From the blog CS@Worcester – Fadi Akram by Fadi Akram and used with permission of the author. All other rights reserved by the author.

This week I read a blog post that I thought really related to the class about why software development is important. The blog is about a deep dive into the career of a software developer. It starts off describing software developers as the masterminds behind computer programs. The blog then gives what different types of software developers do, like how applications software developers are responsible for designing computer or phone apps, and systems software developers are responsible for operating systems level software. Afterwards , the skills needed for software developers are shown. Some of the skills are problem-solving skills, teamwork, motivation, and analytical strategy. The blog ends with the salary of software developers($110,000), and a message to motivate the reader for the future. I selected this blog post because software development is my dream job, and I thought it would be interesting to read about what I should expect for the future job. This blog has a good, in-depth description of how Software Development works, that I think every CS major should read. I think this blog was a great read that I recommend for many reasons. One reason I would recommend this blog is because of how deep it goes into the job of a software developer. The blog goes over what to expect, skills needed, the pay, and does it all at a high level. Another reason I would recommend this blog is because a lot of jobs that we need CS-343 for will all be similar to software development, so even if you do not want to become a software developer, you can still learn something. The last reason I would recommend this blog is because it could get people who don’t like software development into the area by showing them what to expect from the job. Knowing what to expect could really help open the doors for others to be interested in this field. I learned how many of the skills that are needed for software developers I have already like Java, and I also learned the skills that I have not learned yet like DevOps. The material affected me heavily because it showed me what skills to learn, and what to expect if I want my future dream of software development to come true. I will take all the knowledge given to me through this blog into the future by getting better prepared to do this job. Now that I know what to expect from software development, I will try to build on it for the future.

https://www.rasmussen.edu/degrees/technology/blog/what-does-software-developer-do/

From the blog CS@Worcester – Anesti Blog's by Anesti Lara and used with permission of the author. All other rights reserved by the author.

In our most recent class, one of our in class activities mentioned asynchronicity for a JavaScript function. This function required us to use the “await” keyword for us getting data. I’d thus thought of doing a post on concurrency, but in my experience in using concurrency, I’ve noticed myself and others struggling with the difference between concurrency and parallelism. Hence, in order to clearly understand concurrency, I wish to also describe parallelism. 

An application that is neither parallel nor concurrent is one that is processed sequentially, typically one “where it only has a single job that is too small to make sense to parallelize.¹”

Parallelism is simply the separation of a task into multiple sub tasks. These sub tasks are simply parallel if they are worked on sequentially. If two or more sub tasks are being worked at the same time, the program is implementing both parallelism and concurrency.

Concurrency is the act of an application working on two or more parts of an application at the same time. One thread could be running through an array, while another is doing a separate calculation. If an application is running without implementing parallelism, then it is working on each part of the application.

An application that is both parallel and concurrent can partition parts of the application and executes the program’s sub tasks concurrently. It may also include programs that divide a subtask into further subtasks and run those concurrently too.

I picked this particular source because it articulates the difference between concurrency and parallelism, rather than just one or the other. It also has a section that shows the permutations of implementing concurrency, parallelism, both, or neither. Even though I know about parallelism and concurrency, this article in particular helped me visualize them. I did not know that one could implement concurrency without parallelism. 

I feel as through this article will help me understand some elements of homework #5, because it will likely include functions that are asynchronous, and therefore require us to acknowledge it by properly implementing the “await” keyword. While this article was oriented towards locally run applications, this will also aid with applications that are executed to and from servers, by which the topics of parallelism and concurrency will still render useful.

I have also created a program that attempts to implement concurrent execution between multiple sub tasks that exist from implementing parallelism, which this article helped me understand. Specifically, I generate a vector with integers, then split the vector into subtasks which are then run concurrently. Each vector sub task gives the average sum of their respective sub task. 

Links:

1. http://tutorials.jenkov.com/java-concurrency/concurrency-vs-parallelism.html (the proper article sourced for the information)
2. https://github.com/Chris-Archive/Vector-Parallelism-Concurrency (my GitHub repository of the example I used above in C++)

From the blog CS@Worcester – Chris's CS Blog by Chris and used with permission of the author. All other rights reserved by the author.

Hello everyone and welcome to my blog! This week I decided to write a blog on design smells. In programming, we write a lot of code and even a small mistake in the code tends to break the whole program which brings down the efficiency of the code. Design smells refer to the mistakes in the code that had to do with the way the programmer wrote the code which then tends to make a lot of problems due to the design on how the code is written. Design smells are structures in the design that indicate a violation of fundamental design principles and negatively impact design quality. If a programmer focuses less on code design, later the program tends to break easily even if a small feature needs to be added to it. In the article, Mr. Fowler says code smell is a surface indication that usually corresponds to a deeper problem in the system. Design smells are easy to spot if we know about them and what they are, hence, some of the common design smells are:

Rigidity: The program breaks if a single change is made in the code, hence had to go back, and make several changes to make the code work.

• Immobility: the parts of the code if can be used in other system can’t be moved because of the high risk of breaking the original code.

• Fragility: changes in the code that could make error in the different unrelated parts to the program, hence making it difficult to even change small section of the code.

• Viscosity: Making the changes in the program in a right way is harder hence, code is easy to be broken.

• Needless Complexity: having the code that is not useful and make the code hard to understand.

• Needless Repetition: Various Repetition of functions in the code can be removed by refactoring the program.

• Opacity: The functionality of a system or feature is unclear, or the code is unclear and very difficult to understand.

I choose this article because as a programmer above things are something we don’t want in our code, by learning about design smells one can know where to find it in the code and once you find it following the best practices such as refactoring can help solve design smells. As a programmer in the future knowing about these design smells helps me later in my everyday task in my job.

Links used:

https://martinfowler.com/bliki/CodeSmell.html

From the blog CS@Worcester – Mausam Mishra's Blog by mousammishra21 and used with permission of the author. All other rights reserved by the author.