org.dspace.content

The DSpace Data Model

Submissions are created as Workspace Items. A Workspace Item is an Item in progress. Once item assembly is complete, one of two things may happen:

• If the Collection being submitted to has an associated workflow, it is started. At this point the Workspace Item becomes a Workflow Item.
• If the Collection has no associated workflow, the Workspace Item is removed and the assembled Item is included in the Collection.

Using the Content Management API

The classes in this package are then used to create in-memory snapshots that represent the corresponding logical objects stored in the system. When the reading or manipulating is done, the Context may either be aborted, in which case any changes made are discarded, or completed, in which case any changes made are committed to main DSpace storage.

If any error occurs if you are making changes, you should abort the current context, since the in-memory snapshots might be in an inconsistent state.

Typically, when changing a particular object in the system, the changes will not be written to main DSpace storage unless update is called on the object prior to Context completion. Where this is not the case, it is stated in the method documentation.

Instances of the classes in this package are tied to that Context; when the Context has been finished with the objects essentially become invalid.

An example use of the Content Management API is shown below:

try
{
    // Create a DSpace context
    context = new org.dspace.core.Context();

    // Set the current user
    context.setCurrentUser(authenticatedUser)

    // Create my new collection
    Collection c = Collection.create(context);
    c.setMetadata("name", "My New Collection");
    c.update();   // Updates the metadata within the context

    // Find an item
    item = Item.find(context, 1234);
    
    // Remove it from its old collections
    Collection[] colls = item.getCollections();
    colls[0].removeItem(item);
    
    // Add it to my new collection
    c.addItem(item);
   
    // All went well; complete the context so changes are written
    context.complete();
}
catch (SQLException se)
{
    // Something went wrong with the database; abort the context so
    // no changes are written
    context.abort();
}
catch (AuthorizeException ae)
{
    // authenticatedUser does not have permission to perform one of the
    // above actions, so no changes should be made at all.
    context.abort();
}

// The context will have been completed or aborted here, so it may
// no longer be used, nor any objects that were created with it (e.g. item)

When modifying the bitstream metadata, changes are not reflected in the database until update is called.

The corresponding Bitstream objects are loaded into memory.

The collection's metadata (name, introductory text etc), workflow groups, and default group of submitters are loaded into memory.

The community's metadata (name, introductory text etc.) is loaded into' memory.

Dates in the DSpace database are held in the ISO 8601 format.

This class holds in memory the item Dublin Core metadata, the bundles in the item, and the bitstreams in those bundles.

The schema object exposes a name which can later be used to generate namespace prefixes in RDF or XML, e.g.