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Can you create objects from interfaces?
We can’t create instance(interface can’t be instantiated) of interface but we can make reference of it that refers to the Object of its implementing class. A class can implement more than one interface. A class that implements interface must implements all the methods in interface.
Which interface provides factory methods?
Based on the type passed into the Factory object, we are returning the original concrete object as the interface IPerson . A factory method is just an addition to Factory class. It creates the object of the class through interfaces but on the other hand, it also lets the subclass decide which class is instantiated.
What is the use of an object factory?
Typically, an object factory is quite simple and small. Its main role is to collect the information necessary to create an instance of the intended object’s class and then to invoke that class’s constructor. However, the complexity of the objects that it creates can vary significantly.
Can an interface be a type?
When you define a new interface, you are defining a new reference data type. You can use interface names anywhere you can use any other data type name.
CAN interface have main method?
No you cannot, because main has to be static in order to be used as an entry point, and Interfaces dont allow the use of static, until Java 7 .
Which is an example of an objectfactory in Java?
An ObjectFactory is responsible for creating objects of a specific type. In the above example, you may have a PrinterObjectFactory for creating Printer objects. 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 do you need to know about object factories?
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. The getObjectInstance () method of an object factory may be invoked multiple times, possibly using different parameters. The implementation is thread-safe.
How are factories invoked in object oriented programming?
Factories may be invoked in various ways, most often a method call (a factory method ), sometimes by being called as a function if the factory is a function object (a factory function ). In some languages factories are generalizations of constructors, meaning constructors are themselves factories and these are invoked in the same way.
How is a factory function implemented in Python?
In Python, a factory function f that instantiates a class A can be implemented as: A simple factory function implementing the singleton pattern is: This will create an object when first called, and always return the same object thereafter.