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• "Constructing" an object may be misconstrued as the action of creating an object in the DSpace system, for example one might expect something like:

  Code Block
  Context dsContent = new Context(); Item myItem = new Item(context, id)

  to construct a brand new item in the system, rather than simply instantiating an in-memory instance of an object in the system.
• find methods may often be called with invalid IDs, and return null in such a case. A constructor would have to throw an exception in this case. A null return value from a static method can in general be dealt with more simply in code.
• If an instantiation representing the same underlying archival entity already exists, the find method can simply return that same instantiation to avoid multiple copies and any inconsistencies which might result.

Collection, Bundle and Bitstream do not have create methods; rather, one has to create an object using the relevant method on the container. For example, to create a collection, one must invoke createCollection on the community that the collection is to appear in:

Context context = new Context();
Community existingCommunity = Community.find(context, 123);
Collection myNewCollection = existingCommunity.createCollection();

The primary reason for this is for determining authorization. In order to know whether an e-person may create an object, the system must know which container the object is to be added to. It makes no sense to create a collection outside of a community, and the authorization system does not have a policy for that.

Item_s are first created in the form of an implementation of _InProgressSubmission. An InProgressSubmission represents an item under construction; once it is complete, it is installed into the main archive and added to the relevant collection by the InstallItem class. The org.dspace.content package provides an implementation of InProgressSubmission called WorkspaceItem; this is a simple implementation that contains some fields used by the Web submission UI. The org.dspace.workflow also contains an implementation called WorkflowItem which represents a submission undergoing a workflow process.

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