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In Ruby, object creation typically involves using constructors, specifically the `initialize` method within a class. However, static factory methods offer an alternative that can provide additional flexibility, readability, and maintainability. By implementing static factory methods, you can encapsulate object creation logic, enforce specific rules, and even return instances from a pool or cache, all while maintaining a clear and expressive codebase.

Static factory methods in Ruby offer several advantages over traditional constructors: 1. **Improved Naming**: Static factory methods can have descriptive names, making the purpose of the method clear and the code more readable. 2. **Control Over Instantiation**: Static factory methods can control how instances are created, including returning existing instances or subtypes, enhancing flexibility and efficiency. 3. **Encapsulation**: Static factory methods can encapsulate complex object creation logic, keeping the class’s constructor simple and focused.

1. Basic Constructor Using `initialize`

```ruby class Person

 attr_reader :name, :age

 def initialize(name, age)
   @name = name
   @age = age
 end

john = Person.new(“John Doe”, 30) ```

1. Static Factory Method

```ruby class Person

 attr_reader :name, :age

 private_class_method :new  # Make the constructor private

 def self.create(name, age)
   return nil if age < 0  # Validation logic
   new(name, age)
 end

 private

 def initialize(name, age)
   @name = name
   @age = age
 end

john = Person.create(“John Doe”, 30) ```

In this example, the `create` method serves as a static factory method, controlling the instantiation of `Person` objects and allowing for validation before an object is created.

1. Traditional Constructor Approach

```ruby class Logger

 attr_reader :level

 def initialize(level)
   @level = level
 end

logger1 = Logger.new(“INFO”) logger2 = Logger.new(“INFO”) ```

1. Static Factory Method with Caching

```ruby class Logger

 attr_reader :level

 @@instances = {}

 private_class_method :new

 def self.get_logger(level)
   @@instances[level] ||= new(level)
 end

 private

 def initialize(level)
   @level = level
 end

logger1 = Logger.get_logger(“INFO”) logger2 = Logger.get_logger(“INFO”) ```

In this example, `get_logger` is a static factory method that returns a cached instance of `Logger` if it already exists, avoiding the creation of duplicate objects.

1. Traditional Constructor Approach

```ruby class Shape

 attr_reader :type, :size

 def initialize(type, size)
   @type = type
   @size = size
 end

1. Static Factory Method with Subtype Selection

```ruby class Shape

 private_class_method :new

 def self.create_shape(type, size)
   case type
   when "Circle"
     Circle.new(size)
   when "Square"
     Square.new(size)
   else
     raise "Unknown shape type"
   end
 end

class Circle < Shape

 def initialize(radius)
   @radius = radius
 end

class Square < Shape

 def initialize(side)
   @side = side
 end

circle = Shape.create_shape(“Circle”, 10) square = Shape.create_shape(“Square”, 5) ```

In this example, `create_shape` is a static factory method that determines which subtype (`Circle` or `Square`) to create based on the `type` argument, providing flexibility in object creation.

1. Traditional Constructor Approach

```ruby class Account

 attr_reader :balance

 def initialize(balance)
   @balance = balance
 end

account = Account.new(100) ```

1. Static Factory Method for Immutability

```ruby class Account

 attr_reader :balance

 private_class_method :new

 def self.create(balance)
   new(balance.freeze)
 end

 private

 def initialize(balance)
   @balance = balance
 end

account = Account.create(100) ```

In this example, `create` is a static factory method that ensures the `balance` is frozen, creating an immutable `Account` object.

Static factory methods are particularly useful in the following scenarios: - **Complex Object Initialization**: When object creation involves validation, caching, or complex initialization logic, static factory methods provide a clean and maintainable solution. - **Immutability**: For creating immutable objects, static factory methods can enforce immutability while maintaining clarity and simplicity. - **Subtype Creation**: When different subtypes of an object need to be created based on input parameters, static factory methods offer a flexible and extensible approach.

In Ruby, static factory methods offer a powerful alternative to traditional constructors, providing greater control over object creation and improving code readability and maintainability. By using static factory methods, you can encapsulate complex logic, implement caching, and enforce object immutability, making your code more robust and easier to manage. This approach aligns with modern Ruby development practices, where flexibility and clarity are key considerations.

For more information on best practices in Ruby and object-oriented programming techniques, consider exploring the following resources:

• https://ruby-doc.org/core-3.0.0/Class.html
• https://rubystyle.guide/
• https://pragprog.com/titles/ruby3/programming-ruby-3-2-0/

These resources provide additional insights and best practices for writing efficient and optimized code in Ruby.