| AbstractSurrogate | Abstract class implementing Surrogate capabilities to Request and Response instances. |
| Esi | Esi implements the ESI capabilities to Request and Response instances. |
| HttpCache | Cache provides HTTP caching. |
| ResponseCacheStrategy | ResponseCacheStrategy knows how to compute the Response cache HTTP header based on the different response cache headers. |
| Ssi | Ssi implements the SSI capabilities to Request and Response instances. |
| Store | Store implements all the logic for storing cache metadata (Request and Response headers). |
| SubRequestHandler | |