English meaning of encapsulation

• 1. To encase in or as if in a capsule

  2. To express in a brief summary

Technical translation of encapsulation

• 1. Encapsulation can be described as a protective measure that prevents the code and data from being accessed and manipulated by other code defined outside of the class.

  2. Wrapping of data in a construct such that it hides its internal data (use of access modifiers, see list below)

  3. Provide behaviour methods to control access of data in desired fashion (use of setter and getter methods)

Benefits of Encapsulation

• 1. Flexibility:

     1. Makes it easy to model real-world entities – hence easy to understand and maintain

     2. Control the way data is accessed or modified

     3. Gives flexibility to the design: Provides the ability to implement code without breaking the code created by others.

  2. Extensibility:

     1. Makes the class easy to use for clients

     2. Increase reusability

  3. Maintainability:

     1. Provides the easy to update or fix code without interfering with the usage others are making of the classes being maintained.

Encapsulation as an OOP Concept

Encapsulation is one of the four fundamental OOP concepts. The other three are inheritance, polymorphism, and abstraction.

• • • A language feature that enforces information hiding

    • Information hiding is the practice of hiding the details of a module with the goal of controlling access to the details

    • The bundling of data and actions in such a way that the logical properties of the data and actions are separated from the implementation details.

    • Each class encapsulates its data but shares their values through knowledge responsibilities/ through methods

To achieve encapsulation in Java

• 1. Declare the variables of a class as private.

  2. Provide public mutator/setter and accessor/getter methods to modify and view the variables values.

Example

/**

 *

 * @author maanderson

 */

public class Student {

   private String name;

   private int age;

   public Student(String name, int age) {

      this.name = name;

      this.age = age;

   }

   public void setAge(int age) {

      this.age = age;

   }

   public void setName(String name) {

      this.name = name;

   }

   public String getName() {

      return name;

   }

   public int getAge() {

      return age;

   }   

}