Interface SystemHierarchySession

All Superinterfaces:
AutoCloseable, Closeable, OsidSession, OsidSession

public interface SystemHierarchySession extends OsidSession

This session defines methods for traversing a hierarchy of Systems . Each node in the hierarchy is a unique System . The hierarchy may be traversed recursively to establish the tree structure through getParentSystems() and getChildSystems() . To relate these Ids to another OSID, getSystemNodes() can be used for retrievals that can be used for bulk lookups in other OSIDs. Any System available in the Control OSID is known to this hierarchy but does not appear in the hierarchy traversal until added as a root system or a child of another system.

A user may not be authorized to traverse the entire hierarchy. Parts of the hierarchy may be made invisible through omission from the returns of getParentSystems() or getChildSystems() in lieu of a PERMISSION_DENIED error that may disrupt the traversal through authorized deviceways.

This session defines views that offer differing behaviors when retrieving multiple objects.

  • comparative system view: system elements may be silently omitted or re-ordered
  • plenary system view: provides a complete set or is an error condition