Encapsulation is an object-oriented programming principle that focuses on hiding the internal implementation details of a class and providing a well-defined interface to interact with the class. It helps in organizing and structuring code, as well as protecting data from unauthorized access and modification. Encapsulation in Dart is achieved through the use of classes, access modifiers, and getter/setter methods.
Here are the key aspects of encapsulation in Dart:
1. Classes : Classes serve as the building blocks of encapsulation in Dart. A class encapsulates related data (attributes/properties) and behavior (methods/functions) into a single unit. It defines the structure and behavior of objects.
2. Access Modifiers : Dart provides three access modifiers to control the visibility and accessibility of class members (variables and methods):
* Public Access (default) : Class members declared without any access modifier are considered public and can be accessed from anywhere.
* Private Access (_) : By prefixing an identifier with an underscore (_), it becomes private to the library or file in which it is defined. Private members cannot be accessed from outside the defining library or file.
* Protected Access (deprecated) : Dart does not have a built-in protected access modifier. Previously, the `protected` keyword was available, but it has been deprecated.
By using access modifiers appropriately, you can control the visibility of class members and limit their access to specific parts of your code.
3. Getter and Setter Methods : Dart provides getter and setter methods, also known as accessors, to provide controlled access to private class members and enforce data encapsulation. Getters retrieve the value of a private member, and setters allow modification of the value.
* Getter : A getter is a method used to retrieve the value of a private member. It provides read-only access to the member. Getters are defined using the `
get` keyword followed by the method name. For example:
class MyClass {
int _myPrivateVar = 42;
int get myPrivateVar => _myPrivateVar;
}​
* Setter : A setter is a method used to modify the value of a private member. It provides write-only access to the member. Setters are defined using the `
set` keyword followed by the method name. For example:
class MyClass {
int _myPrivateVar = 42;
set myPrivateVar(int value) {
_myPrivateVar = value;
}
}​
By using getter and setter methods, you can encapsulate the internal state of an object and control how the data is accessed and modified.
Encapsulation allows you to define clear boundaries between different parts of your code, making it easier to manage and maintain. It promotes code reusability, as the internal implementation details of a class can be modified without affecting the code that interacts with it. Encapsulation also provides data protection and reduces the likelihood of bugs caused by unauthorized access or modification of class members.
