Encapsulation in Java
Encapsulation is defined as the wrapping up of data under a single unit. It is the mechanism that binds together code and the data it manipulates.Other way to think about encapsulation is, it is a protective shield that prevents the data from being accessed by the code outside this shield.
- Technically in encapsulation, the variables or data of a class is hidden from any other class and can be accessed only through any member function of own class in which they are declared.
- As in encapsulation, the data in a class is hidden from other classes using the data hiding concept which is achieved by making the members or methods of class as private and the class is exposed to the end user or the world without providing any details behind implementation using the abstraction concept, so it is also known as combination of data-hiding and abstraction..
- Encapsulation can be achieved by: Declaring all the variables in the class as private and writing public methods in the class to set and get the values of variables.
// Java program to demonstrate encapsulation public class Encapsulate { // private variables declared // these can only be accessed by // public methods of class private String geekName; private int geekRoll; private int geekAge; // get method for age to access // private variable geekAge public int getAge() { return geekAge; } // get method for name to access // private variable geekName public String getName() { return geekName; } // get method for roll to access // private variable geekRoll public int getRoll() { return geekRoll; } // set method for age to access // private variable geekage public void setAge( int newAge) { geekAge = newAge; } // set method for name to access // private variable geekName public void setName(String newName) { geekName = newName; } // set method for roll to access // private variable geekRoll public void setRoll( int newRoll) { geekRoll = newRoll; } } In the above program the class EncapsulateDemo is encapsulated as the variables are declared as private. The get methods like getAge() , getName() , getRoll() are set as public, these methods are used to access these variables. The setter methods like setName(), setAge(), setRoll() are also declared as public and are used to set the values of the variables.
The program to access variables of the class EncapsulateDemo is shown below:
public class TestEncapsulation { public static void main (String[] args) { Encapsulate obj = new Encapsulate(); // setting values of the variables obj.setName("Harsh"); obj.setAge(19); obj.setRoll(51); // Displaying values of the variables System.out.println("Geek's name: " + obj.getName()); System.out.println("Geek's age: " + obj.getAge()); System.out.println("Geek's roll: " + obj.getRoll()); // Direct access of geekRoll is not possible // due to encapsulation // System.out.println("Geek's roll: " + obj.geekName); } } |
Output:
Favorable circumstances of Encapsulation:
Information Hiding: The client will have no clue about the inward usage of the class. It won’t be obvious to the client that how the class is putting away qualities in the factors. He just realizes that we are passing the qualities to a setter strategy and factors are getting instated with that esteem.
Expanded Flexibility: We can make the factors of the class as perused just or compose just relying upon our necessity. In the event that we wish to make the factors as perused just, at that point we need to overlook the setter techniques like setName(), setAge() and so on from the above program or on the off chance that we wish to make the factors as compose just, at that point we need to discard the get strategies like getName(), getAge() and so on from the above program
Reusability: Encapsulation additionally improves the re-ease of use and simple to change with new prerequisites.
Testing code is simple: Encapsulated code is anything but difficult to test for unit testing.
