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Essentially, encapsulation prevents external code from being concerned with the internal workings of an object. Encapsulation allows developers to present a consistent interface that is independent of its internal implementation. As one example, encapsulation can be used to hide the values or state of a structured data object inside a class.
The class will be accessible to other classes in the same package but will be inaccessible to classes outside the package. When we say that a class is inaccessible, it simply means that we cannot create an object of that class or declare a variable of that class type. The protected access specifier too cannot be applied to a class.
So a primitive wrapper class is a wrapper class that encapsulates, hides or wraps data types from the eight primitive data types, [1] so that these can be used to create instantiated objects with methods in another class or in other classes. [2] [3] The primitive wrapper classes are found in the Java API.
Usually the accessor methods have public visibility while the field being encapsulated is given private visibility - this allows a programmer to restrict what actions another user of the code can perform. [1] Compare the following Java class in which the name field has not been encapsulated:
PHP defines the "magic methods" __getand__set for properties of objects. [9] In this example of a simple class representing a student with only the name stored, one can see the variable name is private, i.e. only visible from the Student class, and the "setter" and "getter" is public, namely the getName() and setName('name') methods.
The class defines the data format or type (including member variables and their types) and available procedures (class methods or member functions) for a given type or class of object. Objects are created by calling a special type of method in the class known as a constructor .
The object methods include access to the object state (via an implicit or explicit parameter that references the object) whereas class methods do not. If the language supports inheritance , a class can be defined based on another class with all of its state and behavior plus additional state and behavior that further specializes the class.
This can require significantly less programming effort if the base class contains many methods providing default behavior and only a few of them need to be overridden within the derived class. For example, in the C# code below, the variables and methods of the Employee base class are inherited by the HourlyEmployee and SalariedEmployee derived ...