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For the VITAL system we are using the www.handle.net handle system. We decided early on that each datastream should have its own unique handle as well as the object as a whole. During development I wrestled with the problem of how to link a PID to a handle ID while still allowing individual datastreams to have handles.

My initial thought was to use the number portion of a PID for the local handle ID. For example llgc-id:100 would give the handle:


Where 10107 is our unique institution ID. The problem arises when you try and give datastreams a unique number which won't conflict with the PID IDs. I discovered the local handle ID doesn't have to be numeric so I used a - symbol as a divider so the format is as follows:


e.g. the Dublin Core datastream for llgc-id:100 would be:


I decided to use the following conventions for traceability:

Datastream Ids: 0-9 Are used for Metadata

* Not Present - Handle to the object
* 0 - Handle to the METS document
* 1 - Handle to the Dublin Core datastream
* 2 - Handle to the RELS-EXT datastream (RDF)
* 3 - XACML Policy for an object (Fedora) POLICY datastream only (ISSUE and PAGE policy do not require handles)
* 4 - METS rights for an object
* 5 - UKETD metadata for an object
* 6 - PREMISRights

10-onwards are used for data e.g. archive level files and derivatives

* 10 - Archive level file
* 11 - Main Reference file (50PNG, JPEG2000, JPEG)
* 12 - zoom
* 13 - thumbnail
* 14 - text
* 15 - coordinates (ALTO)
* 16 - Handle to Benchmarking document
* 17 - AbbyFineReader_XML_output
* 18 - datastream_100_PNG
* 19 - TEI
* 20 - Article - followed by number of article e.g. 20-1 (http://hdl.handle.net/10107/12345-20-1 
* 21 - 650pxPNG
* 22 - textMD

The above datastreams are present in all objects and could be classed as administration datastreams. To keep the image datastreams unique I decided to start their IDS at 10. The order of the images is decided by the order in the ingest METS document.

Some Example handles for object llgc-id:21 (only works internally)

Handle Record

There is more than just the URL stored in the handle record. When a handle points to an object the handle looks as follows:

index=100 type=HS_ADMIN 
index=1 type=URL rwr- "http://dams.llgc.org.uk:8080/fedora/get/llgc-id:21"
index=2 type=FEDORA-PID rwr- "llgc-id:21"

This should allow easy handle resolution. For datastreams the record looks as follows:

index=100 type=HS_ADMIN 
index=1 type=URL rwr- "http://dams.llgc.org.uk:8080/fedora/get/llgc-id:21/METS"
index=2 type=FEDORA-PID rwr- "llgc-id:21"
index=3 type=FEDORA-DS-ID rwr- "METS"


Code available soon. I have created a library which uses the handle.net client libraries available at http://www.handle.net/client_download.html. They are located in the package uk.org.llgc.handles. More details to follow.