Object-Oriented Programming (OOP) languages use objects that contain both data and code. The principles of object oriented programming are encapsulation, abstraction, polymorphism, and inheritance.
Object-oriented programming languages are everywhere we look. Many of the most widely used coding languages that make up the computing world today are object-oriented; many computer programs and much of the content on the web is built on high-level, object-oriented languages. Understanding how object-oriented languages work and why they are useful is important for almost every career in computing.
In this article, we’re going to take a look at what object-oriented languages are, their pros and cons, and a shortlist of some of the most popular OOP languages in use today.
What is an Object-Oriented Programming Language?
Computers are powerful machines. With a computer, we can calculate numbers extremely quickly, and we are able to produce amazing programs for many applications. However, to take advantage of this power, we need to communicate with the computer is something less painful than manually typing ones and zeros.
Therefore, we have programming languages, which are propped up by machine code that’s already been written. However, the further removed we get from machine code the more abstract and specialized languages become in handling data. This is why we have so many different languages; no one language is perfect, and they all have different and overlapping applications.
To this note, programming languages are often separated by their programming paradigm. A programming paradigm is one way of looking at and accessing data. The two primary paradigms are Object-Oriented and Functional, although there are many more (including some that are underlying principles for the above).
Object-Oriented programming is built around objects, data structures that contain both data (properties or attributes) and code (procedures or methods). Objects are able to modify themselves (with ‘this’ or ‘self’) and in most OOP languages almost everything is an object that can have both values and executable code. Each object is unique, and though it may be a copy of another object it’s variables can be different from any other object’s variables.
The objects in object-oriented software design can be thought of like actual objects. Think of an object, like a watch. That watch has properties, it’s made of metal, it’s black in color, it has a specific weight. But that object also does things, it displays the time, and it also can affect itself; spinning gears to change the position of its hands.
Another feature of objects is that we don’t always need to know how the watch functions to get it to function. Assuming the watch is well built it will reliably tell time, without us having to interfere with its inner workings.
Object oriented languages have objects similar to real world objects. They can have properties and functions. They also tend to follow a certain set of principles.
Object-oriented languages come with four principles; common properties that define them and make them significantly more efficient to use. Some people call them the four pillars of object-oriented programming:
- Encapsulation – Encapsulation is the concept of binding data to functions, which works as a security function to keep that data safe. For example, many OOP languages prevent anything other than specific methods in the class owning the data to access that data; this is often done explicitly to keep certain data safe. This also works on a functional level, as it prevents unwanted message passing; code outside of an object from interfering with code and data meant to stay within an object, and vice versa.
- Abstraction – Abstraction is the idea that if you’re doing one thing too often it should be its own entity. If a programmer is rewriting the same function over and over again for different objects, that function could be abstracted to become its own entity, and instanced by any object that requires it.
- Inheritance – Inheritance is what it sounds like, and is most often defined as a “is a” relationship. It lets certain classes be under the umbrella of other classes, and inherit information and functionality from that class, while also being able to expand on that functionality. It lets us reuse code that we’ve already typed in other classes.
- Polymorphism – Polymorphism means to take more than one shape, and in the sense of OOP languages, it refers to the ability to handle objects differently depending on what they are. It allows us to define different methods for handling objects based on their derived class. For example, if we needed to find the size of something, we might change how we measure it based on what it is. if it is a plank of wood I would measure it in inches, as opposed to a volume of water, which I would measure by weight. If we utilize polymorphism, we can create a function that can accept either object and still give us a sane measurement.
|Functional Programming Languages VS Object-Oriented Languages|
|Functional languages are more based on the flow of information manipulated through pure mathematical functions. OOP languages focus more on manipulating data through objects and events. Objects can have different values, but variables in functional languages are immutable.|
The Pros and Cons of Object-Oriented Programming Languages
While OOP languages can be powerful, they aren’t useful for every situation and come with some baggage that must be considered.
- Reusability – Object-oriented code is extremely modular by design, and because of polymorphism and abstraction you can make one function that can be used over and over again, or copy information and functionality that’s already been written with inheritance. This saves time, reduces complexity, saves space, and makes coding a lighter load on our fingers.
- Parallel Development – because of the four pillars, when the main classes are defined there is enough groundwork for parts of the program to be developed separately from each other and still function. This makes concurrent development much easier for larger development teams.
- Maintenance – Because most, if not all, of our code is in one place, being called and reused, that code is much easier to maintain. Instead of having to go through a hundred different instances where a function is called and fix each individually, we can fix the one modular and polymorphic function that’s called a hundred times.
- Security – While most languages have some security, object-oriented languages are convenient because security is built-in with encapsulation. Other methods and classes cannot access private data by default, and programs written in OOP languages are more secure for it.
- Reflects the real world – Because objects in object-oriented programming act like real-life objects, the code is much easier to use and visualize. We think about the world around us this way–of objects having information and functions—so programming this way is a little less challenging.
- Often Messy – Because object-oriented languages are so customizable and scalable, it can be easy to lose an understanding of how the code works. OOP code can function in many ways, and there are many methodologies for programming in OOP that don’t work well with other methodologies, or are just inefficient or difficult to use to begin with. Essentially, as programmers are often allowed too much freedom, that freedom is often abused to make programs that could be much more efficient, or are inherently buggy.
- Requires More Planning – Because these languages are so modular and scalable, going in without a clear design ahead of time is a recipe for disaster. Creating an efficient program requires a solid plan, more so than with other programming paradigms. Programmers need to have a good understanding of what they’re doing to make a program that can be as scalable, efficient, and powerful as the object-oriented language will allow it to be.
- Opacity – This is as much a pro as it is a con. Because objects and functions can operate so independently, taking in information and (usually) spitting out reliable results, they can end up being black boxes—where what they do isn’t always apparent. While the programmer probably created that object and knows what it does, OOP languages simply aren’t as transparent as other languages. In functional languages, all of the code is laid out in front of them instead of being parceled up and hidden away like in object-oriented languages.
- Performance – Object-oriented languages often take a performance hit. Programs made in OOP languages are often larger in size and require more computational effort to run than functional languages. However, this isn’t always true, or important. C++ is an OOP language, but it’s one of the fastest languages available. On the same note, speed isn’t always important, and the difference in speed really only becomes apparent when processing huge or complex calculations, or in instances where extreme speed is required. Otherwise, most programming languages will function at an apparent same speed depending on the function.
Popular Object-Oriented Languages
Now that we have a bit of an understanding of how object-oriented languages function, and where they tend to shine, let’s look at some of the most popular object-oriented programming languages. These languages include:
- Java – Java is everywhere, and it is one of the most used and in-demand languages of all time. Java’s motto is ‘write once, run anywhere,’ and that is reflected in the number of platforms it runs on, and places it’s used.
- Python – Python is general purpose, and used in many places. However, Python has a strong foothold in the machine learning and data science and is one of the preferred languages for that new and ever-growing field.
- C++ – C++ has the speed of C with the functionality of classes and an object-oriented paradigm. It’s a compiled, fast, reliable, and powerful language used in so many applications that it’s even used to build compilers and interpreters for other languages.
Now that you have a firm grasp of what an object-oriented language is, what it’s good for, and which are the most popular, you’re ready to pick one and start learning. Programming in these languages can be as enjoyable as it is profitable, and your career in development is only a few steps away.