Understanding Getter and Setter Methods in Ruby💎

Why?

Getter and setter methods in Ruby provide a controlled way to access and modify the values of instance variables from outside the class. This helps maintain data integrity and adheres to the principle of encapsulation, which means hiding the internal state of an object and only exposing necessary parts.

What?

Getter Methods: Allow reading the value of an instance variable.
Setter Methods: Allow modifying the value of an instance variable.

How?
Ruby simplifies the creation of these methods with attr_accessor, attr_reader, and attr_writer.

attr_reader: Generates only getter methods.
attr_writer: Generates only setter methods.
attr_accessor: Generates both getter and setter methods.

Example

class Product
  attr_reader :name     # Generates only a getter for `name`
  attr_writer :price    # Generates only a setter for `price`
  attr_accessor :stock  # Generates both getter and setter for `stock`

  def initialize(name, price, stock)
    @name = name
    @price = price
    @stock = stock
  end
end

product = Product.new("T-Shirt", 19.99, 10)
puts product.name        # Output: T-Shirt (using getter)
product.price = 24.99    # No getter for `price`, but setter allows modification
product.stock = 5        # Both getter and setter available for `stock`

Listing Instance Variables and Methods

Ruby provides built-in methods to inspect an object's instance variables and methods:

#instance_variables: Returns a list of instance variables.
#public_methods: Returns a list of public methods.

p product.instance_variables  # Output: [:@name, :@price, :@stock]
p product.public_methods      # Output: List of public methods, including `name`, `price=`, and `stock`

By using these tools, you can better understand the structure and capabilities of your objects.

Understanding Getter and Setter Methods in Ruby💎

Table of contents

Example

Listing Instance Variables and Methods