New Features for the Curation System

Introduced in DSpace 1.7, and expanded in 1.8, the Curation System (CS) is still a comparatively new denizen in the DSpace ecosystem. As more tasks and 'suites' are produced, we are learning a lot about what additional functionality the framework could offer to support more powerful, flexible, and easily implemented tasks. This page is intended to be a place to collect these insights, as well as designs that address these needs. Many new features are already being developed, and we welcome participation in their evolution.

Object Selectors

In CS, the unit of curation is a DSpaceObject (which may be an Item, Collection, or Community). Thus the API offers these basic methods (on the Curator class):

public void curate(DSpaceObject object) throws IOException;

public void curate(Context c, String id) throws IOException;

A task may elect to restrict its scope of operation to a particular type or subset of objects (typically, only items, not containers), and can thus apply filters in business logic code to the objects it is given, but often we may wish to perform a given task on a set of objects that do not correspond to any natural container, so filtering will be of no help. For example, we may wish to perform a task on all recently installed items (whatever the collection). We may do this, of course, by writing custom code that pulls the necessary items, then feeds them one-by-one to a curator, but our code is not very portable/repurposable. We could not, e.g., easily use the same code in a command-line context and a UI context, as we have come to expect with CS.

This is the primary motivation for a new feature of the curation API known as object selectors. 'ObjectSelector' is a new interface (which essentially just offers a DSpaceObject Iterator), that is directly supported by the curation API:

public void curate(ObjectSelector selector) throws IOException;

The curator will perform the configured tasks on all the DSpaceObjects delivered by the selector, and the selector can deliver any set of objects it wishes.