Definition and explanation of creational design patterns
As we’ve seen in the previous article, Design pattern gives us an efficient way to handle reappearing problems that a programmer may encounter in its daily experience, this toolkit covers a large range of difficulties that vary : creational, structural and behavioral pattern.
As a first step to cover them all, we’ll shed some light on the creational pattern.
Creational design patterns are crucial design patterns that address object creation mechanisms in software development. They offer solutions to creating objects while hiding the creation logic rather than instantiating objects directly using new operator, which enables flexibility and adaptability to changing requirements over time. The importance of creational design patterns lies in their ability to provide reusable and maintainable code that simplifies the object creation process, thus enhancing the overall software quality and development experience.
To put it more explicitly, this category of design pattern focuses on decoupling the object creation process from other parts of the software program, while considering various constraints that may emerge during the development process. By doing so, creational design patterns enable the creation of objects in a flexible, maintainable, and reusable way.
Types of creational design patterns
Singleton pattern
There are several types of creational design patterns, each with its unique way of handling object creation. The first type is the Singleton pattern, which ensures that a class has only one instance and provides a global point of access to that instance. This pattern is useful when only one instance of an object is needed throughout the application, such as a database connection. The Singleton pattern is straightforward to implement, but it can be challenging to test and maintain because of its global nature. Imagine an application dealing with a database. In this scenario, we only need one instance of the database connection throughout the application, and we want to ensure that there is only one connection to the database. By using the Singleton pattern, we can create a single instance of the connection manager, and all database connections can use this instance. This helps to improve performance and reduce memory consumption.
Factory pattern
The second pattern is the Factory Method pattern, which provides an interface for creating objects in a superclass, but allows subclasses to alter the type of objects that will be created. This pattern is useful when we need to create objects of different types, but we want to keep the creation process decoupled from the rest of the application. The Factory Method pattern is flexible and straightforward to maintain, as it separates the creation process from the rest of the application. However, it can be challenging to extend the Factory Method pattern when we need to create objects with more complex hierarchies.
Suppose we have a UI component library that contains multiple types of UI components, such as buttons, text boxes, and labels, and we want to create them dynamically at runtime. By using the Factory Method pattern, we can define a common interface for creating UI components, and each component can implement this interface in a different way. This allows us to create new UI components dynamically without having to modify the existing code.
The Abstract Factory pattern
The Abstract Factory pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes. This pattern is useful when we need to create families of objects that are related and depend on each other, such as a UI component library. The Abstract Factory pattern is highly decoupled and provides a flexible way of creating objects. However, it can be challenging to extend the Abstract Factory pattern when we need to add new object families to the application.
A real-world example of the Abstract Factory pattern is an automobile manufacturing plant. In this scenario, we have multiple types of automobiles, such as cars, trucks, and buses, and each type has multiple parts, such as engines, tires, and seats. By using the Abstract Factory pattern, we can define a common interface for creating automobile parts, and each type of automobile can implement this interface in a different way. This allows us to create different types of automobiles and their parts dynamically, without having to modify the existing code.
The Builder pattern
The Builder pattern separates the construction of a complex object from its representation, allowing the same construction process to create various representations. This pattern is useful when we need to create complex objects that require multiple steps to be constructed, such as a report or a document. The Builder pattern provides a flexible way of constructing objects while hiding the construction logic from the client code. However, implementing the Builder pattern can be complex, as it requires creating multiple builder classes for each type of object that needs to be constructed.
Think of a report generator. we need to generate reports with different formats, such as PDF, HTML, and CSV, and each format requires a different set of steps to be constructed. By using the Builder pattern, we can define a common interface for constructing reports, and each format can implement this interface in a different way. This allows us to generate reports with different formats without having to modify the existing code.
The Prototype pattern
The fifth type of creational design pattern is the Prototype pattern, which creates new objects by cloning existing ones, rather than creating new objects from scratch. This pattern is useful when we need to create many similar objects with only minor differences, such as a document with different formatting or layout. The Prototype pattern provides a way to create new objects without the overhead of object creation and initialization. However, it can be challenging to implement if the object has complex dependencies, as it requires cloning all the dependencies as well.
In the scenario of a drawing application, we need to create multiple instances of the same object, such as a rectangle, with only minor differences, such as size or color. By using the Prototype pattern, we can define a common interface for creating rectangles and create a prototype object. We can then clone this object multiple times and modify the clones as needed. This allows us to create multiple objects with minor differences efficiently, without having to create new objects from scratch.
In conclusion, the creational design patterns provide a set of solutions to common object creation problems in software design. These patterns help to decouple object creation from the rest of the system, making it easier to modify and maintain the codebase over time. It is important to choose the right creational pattern for the specific problem at hand, taking into account factors such as the complexity of the system, the number of objects to be created, and the desired level of flexibility and extensibility.