Overview

In order to be able to use someone else’s software for your own software project, you must attain a software license. This license establishes the rights and limitations that you have when using the product owner’s software. Software licenses are attained by licensing agreements, where you sign a contract with the owner of the software to use the patented technology.In that contract contain the rights, responsibilities, and limitations you have as a user. I think if you develop some sort of software, it is crucial that you and your team are recognized as the owners of it, and that outside users don’t use it however they feel like. There are many types of software licenses that have different terms and conditions. An article that I read by Ben Lutkevich went more into depth of what a software license and agreement will usually look like, as well as the different types.

Attaining a License

You are about to sign the licensing agreement to officially be able to use someone else’s software. Here’s what to expect. On it will be basic information about both sides. Your name, your address, contact information, as well as the lending party’s. It will contain when the agreement officially goes into effect, and you are able to use the software. It will contain the duration of how long you are able to use the software. It will include how much you have to pay for the software, how many users are eligible. It will give a disclaimer of warranties, as well as maintenance, upgrades and support. Most importantly, it will include the permissions and limitations on distributing the software, user rights of copying and modifying the software. These licensing agreements may differ depending on the type of software license.

Types of Software Licenses

The most common software licenses you find are Proprietary and FOSS. A proprietary software license is commonly referred to as closed-source. Proprietary licenses do not allow users to freely alter the software. Whereas FOSS (Free and Open-Source Software) is the opposite, where the customer is allowed to use the source code and alter the software. FOSS is commonly referred to as open-source. This is the type of license that we will be using in class. Two other licenses that are familiar are Permissive and Copyleft. Permissive software licenses establish some requirements for distribution or modification of the software, and Copyleft notes that licensed code may be distributed or modified as part of a software application or project if all code involved is distributed under the same license. New products containing old code with a copyleft license have the same restrictions as the old code’s license.

Conclusion

If planning to create a software product, it is a smart idea to establish copyright for it, so you are credited for the work you put in. And if you are using someone else’s product for your own product or project, it is the smart decision to attain a licensing agreement, avoiding any potential lawsuits.

Article URL

https://www.techtarget.com/searchcio/definition/software-license#:~:text=A%20software%20license%20is%20a,the%20software%20without%20violating%20copyrights.

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

This week, I wanted to continue writing about the SOLID software design principles. The next principle I have to cover is the Liskov substitution principle. This principle expands upon the Open/Closed principle I wrote about the previous week, providing a guideline on how a superclass and its child classes should behave.

This principle was first defined by Barbara Liskov in 1987, and later adopted by Robert C. Martin. From a paper that Barbara Liskov cowrote with Jeanette Wing, they defined the Liskov substitution principle as a mathematical property: “Let Φ(x) be a property provable about objects x of type T. Then Φ(y) should be true for objects y of type S where S is a subtype of T.”

Translated into plain English, this principle states that instances of a superclass in a program should be able to be replaced by one of its subclasses without breaking the program. Overridden methods from a subclass must accept the same input as the superclass’s original method, and the return value of a subclass’s method must be able to be used the same way as the value returned by a superclass’s original method.

Creating code that abides by this principle isn’t simple, as the compiler can only verify that the structure of your code is correct, not that any specific behavior of your code always executes when desired. Creating robust test classes and cases is the best way to check if your code is following the Liskov substitution principle, checking portions of your program using all subclasses of a particular component to ensure there are no resulting errors or loss in performance.

The author of this article series has included another code example representing a coffee machine to illustrate this design principle, as they have done in their previous articles. They present the problem of creating different subclasses of coffee machines from a generic parent class, with two classes with an “addCoffee()” method that accepts two different types of objects, CoffeeBean and GroundCoffee. The author suggests two solutions, either creating a common Coffee class that can be utilized by both the BasicCoffeeMachine class and the PremiumCoffeeMachine class, or create a common implementation of a “brewCoffee()” method that also appears in both CoffeeMachine classes. The first solution would violate the Liskov substitution principle, because each CoffeeMachine class would need to validate that they are receiving the correct input type for the addCoffee() method, as the BasicCoffeeMachine class can only use the GroundCoffee type, and not the CoffeeBean type. The author’s preferred solution is to remove the addCoffee() method from both CoffeeMachine classes and implement a common brewCoffee() method in the CoffeeMachine interface implemented by BasicCoffeeMachine and PremiumCoffeeMachine. Since all CoffeeMachines are expected to brew filtered coffee grounds, this brewCoffee() method should have that responsibility.

I want to further understand this principle because in a past project, I made a simple video game that used lots of objects of different subtypes that inherited from a single GameObject parent class. If I want to return to that project, or begin a similar one in the future, I want to make sure that I am not losing any functionality as I design and implement subclasses of a broader parent class.

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

SOLID Design Principles

SOLID is a subcategory of five principles, the first being:

Single Responsibility Principle (SRP)

SRP states that a class, module, or function should only have a singular function.

For example, having a class ‘Animal’ with methods ‘displayAnimalName()’, ‘animalSound()’, ‘feedAnimal()’ would be a violation of SRP because each method has a different function. Creating three separate classes that would each represent a functionality resolves the violation. This entails new classes are created for DisplayName, Sound, and Feeding. Although this may lead to more code overall, having separate classes allows for better maintainability. Without SRP, making changes to one functionality may break another.

Open-Closed Principle (OCP)

OCP states that code should be open for extension, but closed for modification. Therefore the code’s behavior should be extended by adding more code rather than modifying the existing code.

Function ‘getArea()’ calculates the area of a shape using a switch statement where there are cases for a square and circle. To add another shape, the switch statement must be modified to add a case for the new shape, violating OCP. To satisfy OCP, one would create separate classes for each shape that implements the Area interface. Now to add a new shape, one would add a new class and implement the Area interface rather than modify the original switch statement.

Liskov Substitution Principle (LSP)

LSP states that child class objects must be substitutable with objects of the parent class without affecting the correctness of the code.

Imagine a parent class ‘Bird’ with method ‘fly()’, and child classes ‘Penguin’ and ‘Eagle’. Both inherit ‘fly()’ because ‘Penguin’ and ‘Eagle’ are child classes of ‘Bird’. Because penguins cannot fly, the ‘fly()’ method in ‘Penguin’ has been overridden to do nothing. Doing this would violate LSP because objects of ‘Penguin’ would not be substitutable for objects of ‘Bird’.

Interface Segregation Principle (ISP)

ISP states that users should not be forced to implement interfaces they will not use.

Imagine an interface ‘Worker’ that has methods ‘work()’ and ‘eatOfficeLunch()’. Classes ‘FieldWorker’ and ‘OfficeWorker’ both implement the ‘Worker’ interface. Because ‘FieldWorker’ does not eat in office, the method ‘eatOfficeLunch()’ is unnecessary. This violates ISP because ‘FieldWorker’ is forced to implement ‘eatOfficeLunch()’ although the method will not be used.

Dependency Inversion Principle (DIP)

DIP states that high-level modules should not depend on low-level modules, keeping that as separate as possible.

For example, there’s a project with high-level systems (backend logic), that relies on low-level modules (database access). However the project’s team wants to change the database from one type to a different. Because the high-level systems are specifically written and depend on the database type, they would no longer work once the database type changes. Having high-level systems be more abstract and able to be implemented in different ways is ideal.

Conclusion

The article used was chosen because it gave examples with code, making understanding easy. As someone who wishes to have a career in software development, knowing the best practices for designing maintainable code is crucial. I expect to apply these principles to all future projects.

Resources:

https://www.freecodecamp.org/news/solid-design-principles-in-software-development/

From the blog CS@Worcester – Zack's CS Blog by ztram1 and used with permission of the author. All other rights reserved by the author.

In the intricate world of software development, as developers strive to create elegant and efficient solutions, they encounter not only best practices but also pitfalls to avoid. These pitfalls, often referred to as anti-patterns, are common design and coding practices that may initially seem like solutions but ultimately lead to more problems than they solve. Understanding and recognizing these anti-patterns is a crucial part of becoming a seasoned software developer.

At its core, an anti-pattern is a recurring design or coding practice that appears to be helpful but is counterproductive in the long run. It’s like a mirage in the desert – promising relief but ultimately leaving you more parched. Anti-patterns often arise from misapplications of well-intentioned ideas or a lack of experience in software development.

One common anti-pattern is known as “Spaghetti Code,” where the codebase becomes entangled and challenging to maintain. While quick fixes and shortcuts may seem like a solution, they often lead to a tangled mess that hampers productivity.

Another notorious anti-pattern is “Cargo Cult Programming,” where developers mimic code without understanding its purpose. This blind imitation can lead to code that lacks context and may introduce errors.

By studying anti-patterns, developers can proactively identify and avoid these pitfalls. It’s akin to recognizing warning signs on the road and taking detours to smoother coding practices. In the ever-evolving landscape of software development, understanding what not to do is as important as knowing what to do. Recognizing anti-patterns empowers developers to make informed decisions and craft robust and maintainable software solutions.

References:

• Anti-patterns
• Design Patterns and Anti-patterns
• Common Anti-Patterns in Software Development

From the blog CS-343 – Hieu Tran Blog by Trung Hiếu and used with permission of the author. All other rights reserved by the author.

Hello and thanks for stopping by to read another round of Comfy Blog. This week, I read up on the apprenticeship pattern “Draw Your Own Map.” I was interested in this pattern immediately once I read the title since I myself am not sure how to walk the long road down the computer science path. For a short summary, this pattern emphasizes the importance of creating your own career path as a software developer and having an understanding that others are not supposed to hold your hand down the path. 

In this pattern, the first step is the most important step, since it is the one that creates all the momentum to your career goals. But what exactly is the first step? Is taking computer science courses in university the first step? Or does the first step skip university classes and is just apply for jobs you are interested in? For me, the first step was realizing my passion for computer science. That passion led me to taking classes in university, and led me to today, my capstone class here at Worcester State University.

Another element that this apprenticeship pattern emphasizes is to set small goals for yourself, rather than set high-level goals and expectations. I think many people’s goals would be to be an employee of a large computer science based company, such as Google, Facebook, or Microsoft. But working there as an apprentice is highly unlikely since you would lack the experience you need. Instead, set small goals and use those small goals as a plan and road map for your career. A small goal would be for example to work at a startup company and develop skills there. Then, maybe move onto a new company down the road that is slightly bigger since you have more skills. There is not a set path that every apprentice should take. Everyone’s path will be different. It is important to note, however, that your small goals roadmap may change as new opportunities open up. My roadmap that I will eventually make may need to constantly change and I may need to go into unfamiliar territory in order to progress.

From the blog Comfy Blog by Angus Cheng and used with permission of the author. All other rights reserved by the author.

Hello and thanks for stopping by to read another round of Comfy Blog. This week, I read up on the apprenticeship pattern “Draw Your Own Map.” I was interested in this pattern immediately once I read the title since I myself am not sure how to walk the long road down the computer science path. For a short summary, this pattern emphasizes the importance of creating your own career path as a software developer and having an understanding that others are not supposed to hold your hand down the path. 

In this pattern, the first step is the most important step, since it is the one that creates all the momentum to your career goals. But what exactly is the first step? Is taking computer science courses in university the first step? Or does the first step skip university classes and is just apply for jobs you are interested in? For me, the first step was realizing my passion for computer science. That passion led me to taking classes in university, and led me to today, my capstone class here at Worcester State University.

Another element that this apprenticeship pattern emphasizes is to set small goals for yourself, rather than set high-level goals and expectations. I think many people’s goals would be to be an employee of a large computer science based company, such as Google, Facebook, or Microsoft. But working there as an apprentice is highly unlikely since you would lack the experience you need. Instead, set small goals and use those small goals as a plan and road map for your career. A small goal would be for example to work at a startup company and develop skills there. Then, maybe move onto a new company down the road that is slightly bigger since you have more skills. There is not a set path that every apprentice should take. Everyone’s path will be different. It is important to note, however, that your small goals roadmap may change as new opportunities open up. My roadmap that I will eventually make may need to constantly change and I may need to go into unfamiliar territory in order to progress.

From the blog Comfy Blog by Angus Cheng and used with permission of the author. All other rights reserved by the author.

Hello and thanks for stopping by to read another round of Comfy Blog. This week, I read up on the apprenticeship pattern “Draw Your Own Map.” I was interested in this pattern immediately once I read the title since I myself am not sure how to walk the long road down the computer science path. For a short summary, this pattern emphasizes the importance of creating your own career path as a software developer and having an understanding that others are not supposed to hold your hand down the path. 

In this pattern, the first step is the most important step, since it is the one that creates all the momentum to your career goals. But what exactly is the first step? Is taking computer science courses in university the first step? Or does the first step skip university classes and is just apply for jobs you are interested in? For me, the first step was realizing my passion for computer science. That passion led me to taking classes in university, and led me to today, my capstone class here at Worcester State University.

Another element that this apprenticeship pattern emphasizes is to set small goals for yourself, rather than set high-level goals and expectations. I think many people’s goals would be to be an employee of a large computer science based company, such as Google, Facebook, or Microsoft. But working there as an apprentice is highly unlikely since you would lack the experience you need. Instead, set small goals and use those small goals as a plan and road map for your career. A small goal would be for example to work at a startup company and develop skills there. Then, maybe move onto a new company down the road that is slightly bigger since you have more skills. There is not a set path that every apprentice should take. Everyone’s path will be different. It is important to note, however, that your small goals roadmap may change as new opportunities open up. My roadmap that I will eventually make may need to constantly change and I may need to go into unfamiliar territory in order to progress.

From the blog Comfy Blog by Angus Cheng and used with permission of the author. All other rights reserved by the author.