Question

What is an accessor method? What is a mutator method?

Short answer

Answer: Accessor methods, also known as getter methods, are used to access or get the value of an object's attribute without directly accessing the attribute, promoting encapsulation. Mutator methods, also known as setter methods, allow the user to modify or set the value of an object's attribute indirectly, maintaining data hiding and integrity. Both methods serve the purpose of promoting encapsulation by restricting direct access to an object's attributes and controlling how the values are accessed or modified.

Step-by-step solution

Definition of Accessor Method

An accessor method, also known as a getter method, is a method that allows the user to access or get the value of an object's attribute without directly accessing the attribute itself. It provides an indirect way to read the attribute's value, ensuring encapsulation or data hiding.

Purpose of Accessor Method

The primary purpose of accessor methods is to promote encapsulation by restricting the direct access to an object's attributes. By providing an indirect way to access attribute values, we can control how the values are manipulated and maintain the integrity of the object's data.

Example of Accessor Method

Let's say we have a class called `Person` with an attribute called `name`. An accessor method for retrieving the `name` attribute would look like this in Python: ```python class Person: def __init__(self, name): self.__name = name def get_name(self): return self.__name ``` Here, the `get_name` method is the accessor method that returns the value of the `__name` attribute.

Definition of Mutator Method

A mutator method, also known as a setter method, is a method that allows the user to modify or set the value of an object's attribute without directly accessing the attribute itself. It provides an indirect way to update the attribute's value, maintaining encapsulation or data hiding.

Purpose of Mutator Method

The primary purpose of mutator methods is to promote encapsulation by restricting the direct access to an object's attributes. By providing an indirect way to modify attribute values, we can control how the values are updated, validate new values before assigning them, and maintain the integrity of the object's data.

Example of Mutator Method

Continuing the example with the `Person` class, a mutator method for updating the `name` attribute would look like this: ```python class Person: def __init__(self, name): self.__name = name def get_name(self): return self.__name def set_name(self, new_name): if isinstance(new_name, str) and len(new_name) > 0: self.__name = new_name else: print("Invalid name value") ``` Here, the `set_name` method is the mutator method that sets a new value to the `__name` attribute after validating the given input.