# Package org.eclipse.incquery.runtime.api.scope

- Interface Summary
  Interface | Description
  --- | ---
  IBaseIndex | Represents the index maintained on the model.
  IEngineContext | The context of the engine is instantiated by the scope, and provides information and services regarding the model the towards the engine.
  IEngineContext.IQueryBackendInitializer |
  IIndexingErrorListener | This interface contains callbacks for various internal errors from the `base index`.
  IInstanceObserver | Listener interface for lightweight observation of changes in edges leaving from given source instance elements.
  IncQueryBaseIndexChangeListener | Listener interface for change notifications from the IncQuery Base index.

- Class Summary
  Class | Description
  --- | ---
  IncQueryScope | Defines a scope for the IncQuery engine, which determines the set of model elements that query evaluation operates on.