Overview of common customizations

This is a list of interfaces or abstract classes in DD4T that are very commonly implemented cq. extended.

Interface	Rationale	Examples	Known customers	Priority	Notes
ILogger	Implement a different logging mechanism	Serilog, MEF	Essity, Ecclesiastical	High
IDependencyMapper	Add dependency mapping independently from any DI implementation	For custom DI implementations: read dependency mappings For any other customization: write dependency mappings	Essity, Ecclesiastical	Very High
DD4T ViewModel base attributes	See ViewModel base attributes for a complete overview	Various extensions to the ViewModel attributes	Fujitsu, Essity, Ricoh	High
ICacheAgent	Implement a different caching mechanism	Redis, serialized cache agent	Essity, Ecclesiastical	High
IPublicationResolver	Implement a custom publication resolving mechanism	Common practice is to create a publication resolver wrapped around the DynamicMappingsRetriever (which isn't out of the box in DD4T). Other use cases would be to use browser settings or Geolocation.	Many	Low	In Web 8 one could argue that the DynamicMappingsRetriever is always an improvement, and DXA 2.0 does not support older Tridion versions.