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Introduction : Encapsulation is one of the fundamental concepts of object-oriented programming (OOP), and it plays a crucial role in designing robust and maintainable software systems. In Java, encapsulation is the process of wrapping data and behavior within an object, providing a level of abstraction and protection from direct access and modification. By using encapsulation, developers can hide the internal details of a class, reduce the coupling between objects, and increase the overall stability and security of a system.
In this article, we will briefly discuss about what OOP is, the four basic concept of OOP, the basics of encapsulation in Java and explore some best practices for achieving encapsulation in your code. I hope this article will help provide valuable insights and practical tips to help you improve your OOP skills and build better applications.
Prerequisites : In order to understand the example of implementing encapsulation in java I will be using, it is necessary that you have prior knowledge of programming language (i used java in this article).
let’s GO !
Before we delve into the topic of encapsulation in Java, let us first have a brief overview of Object-Oriented Programming (OOP) and its fundamental principles.
what is Object-Oriented Programming (OOP) ?
Object-Oriented Programming (OOP) is a programming paradigm that is based on the concept of “objects”, An object is a combination of data and behavior, which can represent a real-world entity, such as a person, a car, or a bank account. OOP provides a way to organize code and create reusable, modular components that can interact with each other.
In OOP, the behavior of an object is defined by its methods, and the data is stored in fields or properties.
The four basic principles of OOP are:
Encapsulation: Encapsulation is the mechanism of wrapping data and functions within an object, hiding the implementation details from the outside world. This helps in protecting the data from unauthorized access and modification, and ensures that the object’s behavior remains consistent even if the implementation changes.
Abstraction: Abstraction refers to the ability to focus on the essential features of an object, ignoring the non-essential details. In OOP, abstraction is achieved through classes, which provide a blueprint for objects
Inheritance: Inheritance is the mechanism of creating new classes based on existing classes. The new classes inherit the properties and behaviors of the existing classes, and can also add new features and modify existing ones. This helps in creating a hierarchical class structure and promotes code reusability.
Polymorphism: Polymorphism is the ability of an object to take on many forms. In OOP, polymorphism is achieved through method overriding and method overloading, which allow objects of different classes to respond to the same method call in different ways.
These principles work together to provide a structured and organized approach to programming, and help to promote software modularity, maintainability, and extensibility.
To read more about OOP and its principles, check out
check out this article from Educative.
check out this article from spiceworks
Now let me talk about how we can achieve encapsulation in java, there are various ways to achieve encapsulation in java.
There are several best practices for achieving encapsulation in Java:
Declare instance variables as private: This ensures that the variables can only be accessed within the class and not from outside.
Use getters and setters: Getters and setters provide controlled access to the instance variables. This allows you to validate data before setting the value and perform additional actions after getting the value.
Use constructor arguments to set required values: This allows you to set required values for an object and ensures that these values are set when the object is created.
Avoid using public static variables: Public static variables can be accessed from anywhere in the code and their values can be changed by any part of the code. Instead, use private static variables and provide getters and setters if necessary.
Using access modifiers
One of the most important ways to achieve encapsulation in Java is through the use of access modifiers. Java provides several access modifiers such as public, private, protected, and default, that allow you to control the visibility of your class members. For example, you can make a class member private by using the private access modifier. This makes the member only accessible within the class, making it impossible for any other class to access it directly.
In java encapsulation can be achieved by using access modifiers such as private and public to control the visibility of class variables and methods.
public class Employer {
private String name;
private String address;
}
The java code above is an “Employer” class with two private variables of type String, named “name” and “address”.
Using the getter and setter methods
Another way to achieve encapsulation in Java is through the use of getter and setter methods. Getter methods allow you to retrieve the value of a class member, while setter methods allow you to set the value of a class member. You can make a class member private and only provide access to it through these methods. This way, you can ensure that the value of a class member can only be changed through the setter method and that it can only be retrieved through the getter method. This ensures that the data is protected and that it can only be accessed through well-defined interfaces.
public class Employer {
private String name;
private String address;
public String getName(){
return name;
}
public void setName(String name){
this.name = name;
}
public String getAddress(){
return address;
}
public void setAddress(String address){
this.address = address;
}
}
The code above defines a Java class called “Employer”. It has two private instance variables, “name” and “address”, which are both of type String. This means that these variables can only be accessed within the class.
The class also provides four methods:
getName()- returns the value of the "name" instance variable.setName(String name)- sets the value of the "name" instance variable to the value passed as an argument.getAddress()- returns the value of the "address" instance variable.setAddress(String address)- sets the value of the "address" instance variable to the value passed as an argument.
These methods are used to access and update the private variables from outside the class. The use of getters and setters is considered a good practice as it provides a level of abstraction and encapsulation to the class. The this keyword is used to refer to the current instance of the class within its own methods.
The principle of encapsulation is achieved by keeping the variables private and exposing public get and set methods. This allows us to hide the internal state of the student object and protects it from unauthorized access and modification.
By doing so, we can change the implementation of the student object in the future without affecting the client code, making the code more maintainable and flexible. Encapsulation provides a level of abstraction that is crucial for software development.
In summary, OOP provides a powerful and flexible way to model real-world entities and organize code, making it easier to create complex software systems that are easier to maintain and evolve over time.