The Factory (or Factory Method) is a creational design pattern responsible for managing the creation of instances of concrete classes through abstract factories. This pattern allows the extension or addition of new concrete classes without violating the Open-Closed principle from SOLID.
For example, consider a VideoExporter factory that supports multiple video encoding formats. The factory is responsible for creating the specific concrete classes, all of which inherit from a common VideoExporter interface or abstract class. The same principle applies to an AudioExporter factory, which similarly handles the creation of audio exporting objects.
In this pattern, a controller or mapping structure is often used to determine which factory to call based on the desired functionality. While this introduces a potential point of failure, it also enables easy expansion of the software, allowing new video or audio exporters to be added as the software grows.
- Flexibility: Enables the software to easily accommodate new exporters or classes without significant code changes.
- Adheres to Open-Closed Principle: New classes can be added without modifying existing code, keeping the system modular.
A VideoExporter factory can handle different video encoding formats, creating concrete classes like H264BPVideoExporter, H264HI422PVideoExporter, or LossLessVideoExport, each implementing a common interface. Similarly, an AudioExporter factory could manage audio exporting formats.