The evidence controller is responsible for the majority of business processing required to maintain evidence. It provides a balance between the common infrastructure applied across all evidence types for maintaining evidence and any parts of evidence maintenance which have been customized to meet business requirements.
Common logic is provided in the evidence controller for enacting the steps in the processes which form part of the overall evidence pattern. This prevents this logic from having to be repeated across all evidence types in a custom evidence solution.
To provide a balance, the evidence controller also orchestrates the logic specific to an evidence type. It contains methods which call evidence interface methods for the evidence types. Each custom evidence entity, therefore, must implement this interface to take part in the evidence pattern.