Examples of EntityIdentifierReader

Identifiers are read from the ResultSet in 2 distinct phases:

First we hydrate the identifier values (see {@link #hydrate}). During this "phase" 2 things happen:
1. Any "optional identifier" specified on QueryParameters is considered. If the "optional identifier" is to be used for this identifier read, it is used to build an EntityKey which is associated with the {@link ResultSetProcessingContext.EntityReferenceProcessingState} for the EntityReference under{@link ResultSetProcessingContext.EntityReferenceProcessingState#registerEntityKey}
2. All other id values are hydrated from the ResultSet. Those hydrated values are then registered with the {@link ResultSetProcessingContext.EntityReferenceProcessingState} for the EntityReferenceunder {@link ResultSetProcessingContext.EntityReferenceProcessingState#registerIdentifierHydratedForm}
Then we resolve the identifier. This is again a 2 step process:
1. For all fetches that "come from" an identifier (key-many-to-ones), we fully hydrate those entities
2. We then call resolve on root identifier type, and use that to build an EntityKey,which is then registered with the {@link ResultSetProcessingContext.EntityReferenceProcessingState} for theEntityReference whose identifier we are reading under {@link ResultSetProcessingContext.EntityReferenceProcessingState#registerEntityKey}

@author Steve Ebersole