Contents
What is the purpose of a factory class?
The stated purpose of the Factory Patterns is: Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.
What is disadvantage of factory pattern?
One disadvantage of the Factory Method pattern is that it can expand the total number of classes in a system. Every concrete Product class also requires a concrete Creator class. The parameterized Factory Method avoids this downside.
What does class factory mean?
In the strictest sense a Class Factory is a function or method that creates or selects a class and returns it, based on some condition determined from input parameters or global context. This is required when the type of object needed can’t be determined until runtime.
Why is factory pattern bad?
That’s just a bad habit. The Factory Method is a design pattern that relies on inheritance. If you make it static , you can no longer extend it in subclasses, which defeats the purpose of the pattern. When a static creation method returns new objects it becomes an alternative constructor.
What problem does factory pattern solve?
In class-based programming, the factory method pattern is a creational pattern that uses factory methods to deal with the problem of creating objects without having to specify the exact class of the object that will be created.
What are factories used for?
A factory, manufacturing plant or a production plant is an industrial site, often a complex consisting of several buildings filled with machinery, where workers manufacture items or operate machines which process each item into another.
What are the benefits of the simple factory pattern?
The Advantages of the Simple Factory Pattern
- It provides an elegant way to abstract your code so there’s less visual clutter.
- It allows you to introduce specialized, focused classes with a single purpose (which is great if you follow the SOLID principles)
What is the disadvantage of abstract factory?
3 Answers. Quoting from “Design Patterns” by GoF (kind of programmer bible): “Supporting new kinds of products is difficult. Extending abstract factories to produce new kinds of Products isn’t easy. That’s because the AbstractFactory interface fixes the set of products that can be created.
Can we create immutable class in Java?
Immutable class in java means that once an object is created, we cannot change its content. In Java, all the wrapper classes (like Integer, Boolean, Byte, Short) and String class is immutable. We can create our own immutable class as well. The class must be declared as final so that child classes can’t be created.
When should I use factory pattern?
The Factory Method pattern is generally used in the following situations:
- A class cannot anticipate the type of objects it needs to create beforehand.
- A class requires its subclasses to specify the objects it creates.
- You want to localize the logic to instantiate a complex object.
What is the factory problem?