Spring — Factory Pattern | Code Factory

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• What is factory and use of factory?
• We use to create object of other classes.
• * Factory classes main aim is to they will make clients independent by returning object in the form of Interface reference.
• * Example: DriverManager is a factory class. Connection is an interface. DriverManager.getConnection() method will return object of Connection irrespective of database. Same code is use for any database so it will making us database independent.
• By factory we will hide object creation logic.
• * Logger is a static factory and SessionFactory is a instance factory.
• Some points of factory
  - Hide instantiation logic
  - By returning instance into Interface reference Factory will make clients independent irrespective of implementation
• Many databases given implementation for Connection interface.

interface Car {
	public void drive();
}
class CarFactory {
	private CarFactory() {
	}
	public static Car getCar(String carName) {
		return (Car) Class.forName(carName).newInstance();
	}
}
class JLR implements Car {
	public void drive() {
		sop("Maximum speed is 250");
	}
}
class Audi implements Car {
	public void drive() {
		sop("Maximum speed is 200");
	}
}
class Test {
	psvm(String args[]) {
		Car c = CarFactory.getCar("JLR");
	}
}

• To implement factories in Spring we have 3 approaches.

1. Spring — Static Factories
2. Spring — Instance Factories
3. Spring — FactoryBean