OAIzer : customized OAI-ORE and OAI-PMH exports of compound objects for the Fedora repository

Modern Digital Library Systems (DLSs) are based on docu- ment models which surpass the traditional payload-metadata document model to incorporate further entities involved in the research life-cycle. Such DLSs manage graphs of interconnected objects, hence oer tools for the creation, visualization and exports of such graphs. In particular, ob- jects in the graph are exported via standard OAI-ORE and OAI-PMH pro- tocols, encoded as (XML) packages of interlinked information objects", also known as compound objects. Fedora is a well-known repository plat- form, designed to support the realization of DLSs implementing modern document models. To date, Fedora does not provide tools to customize compound object exports from DLS object graphs. This paper presents Fedora-OAIzer, an extension of Fedora which allows DLS developers to customize the structure of compound objects to be exported from a given DLS document model { expressed in terms of Fedora Content Models { and to select the OAI protocol of preference. In order to prove the com- pleteness of the approach, Fedora-OAIzer is compared to other solutions for exporting compound objects from Fedora repositories.