Can abstract factory use singleton pattern?

Can abstract factory use singleton pattern?

Summary: The specific factory can be used as a singleton. In general, singleton classes cannot be inherited. Singleton pattern can be transformed into abstract pattern to reuse code.

Can an abstract class be a singleton?

The Singleton pattern requires a private constructor and this already makes subclassing impossible. You’ll need to rethink your design. The Abstract Factory pattern may be more suitable for the particular purpose. The purpose of the private constructor in the Singleton is to prevent anyone else instantiating it.

Can a factory be a singleton?

A factory implemented as a singleton is actually an example of the Service Locator pattern. This is a role which is usually served by your IOC container, of which there should normally be only one instance in your project, invoked only at the topmost level of your code to create all your dependent services.

What is singleton and factory in Java?

Singleton – Ensures that at most only one instance of an object exists throughout application. Factory Method – Creates objects of several related classes without specifying the exact object to be created. Abstract Factory – Creates families of related dependent objects.

What is the difference between factory and prototype patterns?

Factory pattern is used to introduce loose coupling between objects as the factory will take care of all the instantiation logic hiding it from the clients. Prototype pattern on the other hand is used when the cost of creating an object is large and it is ok to copy an existing instance than creating a new instance.

What is abstract class in Java?

Abstract class: is a restricted class that cannot be used to create objects (to access it, it must be inherited from another class). Abstract method: can only be used in an abstract class, and it does not have a body. The body is provided by the subclass (inherited from).

Should Java factory be static?

Static factory methods are essentially named constructors, so yes, they must be static. I’m not familiar with instance factory methods, unless you are referring to the Abstract Factory pattern which has instance methods that are factories, but that is a different concept.

Is a factory always static?

No, factory class by default shouldn’t be static. Actually, static classes are not welcomed in OOP world since they can also convey some state and therefore introduce global application state. If you need only one factory object to be present, you can control it’s creation through singleton pattern.

What is a factory singleton?

A singleton pattern ensures that you always get back the same instance of whatever type you are retrieving, whereas the factory pattern generally gives you a different instance of each type. The purpose of the singleton is where you want all calls to go through the same instance.

What is factory method 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).

How do you implement a prototype design pattern in Java?

Design Patterns – Prototype Pattern

1. Create an abstract class implementing Clonable interface.
2. Create concrete classes extending the above class.
3. Create a class to get concrete classes from database and store them in a Hashtable.
4. PrototypePatternDemo uses ShapeCache class to get clones of shapes stored in a Hashtable.

Does Prototype require subclassing?

Prototype doesn’t require subclassing, but it does require an “initialize” operation. Factory Method requires subclassing, but doesn’t require Initialize. Designs that make heavy use of the Composite and Decorator patterns often can benefit from Prototype as well.

How does a singleton factory work in Java?

So a singleton factory that is responsible for creating objects makes use of the getInstance method to return the same object (which is there in the class) again and again. So how do we implement the Singleton Pattern in a Program?

What does abstract factory pattern mean in Java?

Abstract Factory Pattern Abstract Factory Pattern says that just define an interface or abstract class for creating families of related (or dependent) objects but without specifying their concrete sub-classes. That means Abstract Factory lets a class returns a factory of classes.

How are abstract factories used in client software?

Client software creates a concrete implementation of the abstract factory and then uses the generic interfaces to create the concrete objects that are part of the family of objects. The client does not know or care which concrete objects it gets from each of these concrete factories since it uses only the generic interfaces of their products.

Which is the abstract class in Java builder?

Builder Abstract class: An abstract class containing prototypes of all the functionality required to build a complex object. ConcreteBuilder Class: This is a concrete class that inherits from the Builder class and creates a particular complex object. We can have as many ConcreteBuilder classes as we need.