Use Case 36 - Resolve an Object Location

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Goal

Communicate the locations where a DataONE object can be found

Summary

Within DataONE, a registered object may be held on one or more Member Nodes (depending on replication policy) and in the case of science metadata, on Coordinating Nodes. Clients must be able to ask a Coordinating Node for those locations.

The response to this query is a list of member node identifiers and the URL endpoint of their DataONE API implementation.

The client will need to retrieve information about the node from the node registry (Use case 35) in order to accurately determine the URL that can be used to retrieve the object bytes (Use case 01).

Actors

• Coordinating Node
• Client requesting info

Preconditions

• Coordinating Nodes are operational
• Client has an identifier for an object
• Object exists in the DataONE system and has been recorded by the Coordinating Nodes

Triggers

• Request by client

Post Conditions

• Client has more information about the location of the object.

Figure 1. Use case diagram for Use Case 36.

Figure 2. Sequence diagram for implementation of use case 36.