Apollo is the applicatin object through which all requests are handled.

Collection holds key data about a collection; its PID and Title.

CollectionHit contains all of the search hits grouped by collection.

ControlledValue is a controlled vocabulary for node values.

DB wraps the database connection object.

Node is a single element in a tree of metadata.

NodeIdentifier holds the primary apollo IDs for an item; PID and ID.

NodeType is a controlled vocabulary for node names.

SearchHit is one match found in the search.

SearchResults contains all of the results for a search operation.