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Why do we need Abstract factory design pattern?

Most of the definition says:

An abstract factory provides an interface for creating families of related objects without specifying their concrete classes

What is the use of Abstract Factory Pattern as we can achieve the task via creating object of concrete class itself. Why do we have a factory method that creates object of Concrete class?

Please provide me any real life example where I must implement abstractFactory pattern?

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Amit Avatar asked Feb 17 '10 11:02

Amit


People also ask

Why do we use Abstract Factory pattern?

The purpose of the Abstract Factory is to provide an interface for creating families of related objects, without specifying concrete classes. This pattern is found in the sheet metal stamping equipment used in the manufacture of Japanese automobiles.

What benefit does the Abstract Factory pattern provide?

The Abstract Factory pattern helps you control the classes of objects that an application creates. Because a factory encapsulates the responsibility and the process of creating product objects, it isolates clients from implementation classes. Clients manipulate instances through their abstract interfaces.

Why do we need factory design pattern?

Advantage of Factory Design Pattern Factory Method Pattern allows the sub-classes to choose the type of objects to create. It promotes the loose-coupling by eliminating the need to bind application-specific classes into the code.

What is the use of Abstract Factory design pattern in Java?

Abstract Factory is a creational design pattern, which solves the problem of creating entire product families without specifying their concrete classes. Abstract Factory defines an interface for creating all distinct products but leaves the actual product creation to concrete factory classes.


2 Answers

Abstract Factory is a very central design pattern for Dependency Injection (DI). Here's a list of Stack Overflow questions where application of Abstract Factory has been accepted as the solution.

To the best of my understanding, these questions represent real concerns or problems that people had, so that should get you started with some real-life examples:

  • Is there a pattern for initializing objects created via a DI container
  • Can't combine Factory / DI
  • WCF Dependency injection and abstract factory
  • How to set up IoC when a key class needs Session (or other context-specific variable)
  • How to Resolve type based on end-user configuration value?
  • Strategy Pattern and Dependency Injection using Unity
  • Abstract factory pattern on top of IoC?
  • Is this the correct way to use and test a class that makes use of the factory pattern?
  • DDD Book, Eric Evans: Please explain what is meant by "The FACTORY should be abstracted to the type desired rather than the concrete class(es) created."
  • DI container, factory, or new for ephemeral objects?
  • How to unit test instance creation?
  • What is the best strategy for Dependency Injection of User Input?
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Mark Seemann Avatar answered Oct 07 '22 17:10

Mark Seemann


A real life example for the use of the Abstract Factory pattern is providing data access to two different data sources. Assume your application supports different data stores. (e.g. a SQL Database and an XML file). You have two different data access interfaces e.g. an IReadableStoreand IWritableStore defining the common methods expected by your application regardless of the type of data source used.

Which type of data source shall be used shouldn't change the way client code retrieves it's data access classes. Your AbstractDataAccessFactory knows which type of data source is configured and provides a concrete Factory for the client code, i.e. SqlDataAccessFactory or XmlDataAccessFactory. These concrete factories can create the concrete implementations, e.g. SqlReadableStore and SqlWriteableStore.

The DbProviderFactory in .NET Framework is an example of this pattern.

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Johannes Rudolph Avatar answered Oct 07 '22 15:10

Johannes Rudolph