What is Factory Method Pattern in Java?

What is Factory Method Pattern in Java?

Factory method is a creational design pattern which solves the problem of creating product objects without specifying their concrete classes. Factory Method defines a method, which should be used for creating objects instead of direct constructor call ( new operator).

What is a factory class Java?

A Factory Pattern or Factory Method Pattern says that just define an interface or abstract class for creating an object but let the subclasses decide which class to instantiate. In other words, subclasses are responsible to create the instance of the class.

What is the factory method patterns explain with examples?

Example. The Factory Method defines an interface for creating objects, but lets subclasses decide which classes to instantiate. Injection molding presses demonstrate this pattern. Manufacturers of plastic toys process plastic molding powder, and inject the plastic into molds of the desired shapes.

How do you write a factory class in Java?

Design Pattern – Factory Pattern

1. Implementation.
2. Create an interface.
3. Create concrete classes implementing the same interface.
4. Create a Factory to generate object of concrete class based on given information.
5. Use the Factory to get object of concrete class by passing an information such as type.
6. Verify the output.

What are the types of factory pattern?

the abstract factory pattern, the static factory method, the simple factory (also called factory).

What type of design pattern is factory?

Factory method is a creational design pattern, i.e., related to object creation. In Factory pattern, we create objects without exposing the creation logic to the client and the client uses the same common interface to create a new type of object.

Where is factory design pattern used?

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.

Which are the three types of factory method?

There are 3 types of factory design pattern.

• Simple factory.
• Factory method.
• Abstract factory.

What is an object factory in Java?

An ObjectFactory is responsible for creating objects of a specific type. An object factory must implement the ObjectFactory interface. In addition, the factory class must be public and must have a public constructor that accepts no parameters.

What is the purpose of factory pattern?

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.

Why do we need factory pattern in Java?

Factory design pattern is used to create objects or Class in Java and it provides loose coupling and high cohesion. Factory pattern encapsulate object creation logic which makes it easy to change it later when you change how object gets created or you can even introduce new object with just change in one class.

What is the use of factory class?

Factory classes are useful when you need a complicated process for constructing the object, when the construction need a dependency that you do not want for the actual class, when you need to construct different objects etc.

What is factory design pattern in Java?

The factory design pattern says that define an interface (A java interface or an abstract class) and let the subclasses decide which object to instantiate. The factory method in the interface lets a class defer the instantiation to one or more concrete subclasses.

What is super class in factory design pattern in Java?

Super class in factory design pattern can be an interface, abstract class or a normal java class. For our factory design pattern example, we have abstract super class with overridden toString () method for testing purpose. Let’s say we have two sub-classes PC and Server with below implementation.

What is the most used design pattern in Java?

Design Pattern – Factory Pattern. Factory pattern is one of the most used design patterns in Java. This type of design pattern comes under creational pattern as this pattern provides one of the best ways to create an object.

What is the use of factory method in interface in Java?

The factory method in the interface lets a class defer the instantiation to one or more concrete subclasses. Since this design patterns talk about instantiation of an object and so it comes under the category of creational design pattern.