Factory design pattern in java pdf

You can handle such scenario according to your requirement. In this tutorial, we discussed Factory Method Pattern. This creational pattern is one of the commonly used pattern in frameworks. We hope this tutorial was helpful. Real-life example There are different types of tables, like dining table, study table and so on.

Programming example There are different type of databases like Oracle, MySql and so on. I protect. I destroy. I am Villain. Exception in thread "main" java. Exception: Character: Father cannot be instantiated at com. The Factory method lets a class defer instantiation to subclasses. Page content. Overview When to use Factory Design Pattern? How to implement Factory Design Pattern?

Advantages of Factory Design Pattern. Virtual Constructor This pattern replaces the direct object construction calls using new operator from client with calls to factory method. When to use Factory Design Pattern? In Java constructors are not polymorphic, but by allowing subclass to create an object, we are adding polymorphic behavior to the instantiation.

In short, we are trying to achieve Pseudo polymorphism by letting the subclass to decide what to create, and so this Factory method is also called as Virtual constructor.

Problem Statement : Consider we want to implement a notification service through email, SMS, and push notification. First we will design a UML class diagram for this. In the above class diagram we have an interface called Notification , and three concrete classes are implementing Notification interface. A factory class NotificationFactory is created to get a Notification object. Create all implementation classes SMSNotification. Calendar, NumberFormat, and ResourceBundle uses factory method design pattern.

All the wrapper classes like Integer, Boolean etc, in Java uses this pattern to evaluate the values using valueOf method. DriverManager getConnection , java. Conclusion So far we learned what is Factory method design pattern and how to implement it. I believe now we have a fair understanding of the advantage of this design mechanism. Skip to content.