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- A specific Fedora object, its children objects, and associated Datastreams can be exported
- The serialization of the Fedora object is more portable than the compact form found in the backup/restore feature
- Exported objects are serialized in a standard JCR/XML format
- An exported object or hierarchy of objects can be imported at any time
Versioning
- Versions can be created across the entire repository or on particular API calls.
- A previous version can be restored via the REST-API.
Policy-Driven Storage
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- Different types of
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- content can be routed to different back-end
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- stores on ingest
- Policies can be written to route content based on properties (e.g. filetype)
Data Modelling
Nodes
- Both objects and datastreams are represented as nodes.
- Object nodes can have both Objects and Datastreams as children.
- The tree structure allows for inheritance of things like security policies.
Properties
- Nodes have a number of properties, which are expressed as RDF triples.
- The node itself is the implicit subject of each triple.
- Properties can be RDF literals (e.g. dc:title) or they can express relationships both internal and external to the repository.
- Any number of RDF namespaces can be defined and used.
Content Models
- Content can be modelled using Compact Node Definitions (CNDs).
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- Mixins can be used to define
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- any number of properties
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- . A mixin can be added to a CND to be applied to objects.
- An object can inherit properties from any number of mixins; their effects are cumulative.
Linked Data
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- Fedora 4.0 is compliant with the LDP 1.0 spec.
Node properties are RDF triples.
- Metadata can be represented as RDF triples that point to objects outside the repository.
- Many possibilities for exposing, importing, sharing resources with other web applications.
User Interface
Administrative Console
Tour of the HTML administrative interface.
Internal Search
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- Internal search can search across all node properties.
- It also functions as a limited SPARQL endpoint.
External Components
Indexing
Triplestore
Similar to external search, an external triplestore can be plugged into Fedora 4. The same JMS message consumer relays repository events to the triplestore index (e.g. Fuseki, Sesame).
External Search
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- Indexing repository content for external applications can be accomplished by using the JMS Message Consumer web application.
- This is just one possible implementation - different message consumer implementations could be written.
- The JMS Message Consumer receives JMS messages on repository updates and relays these messages to one or more external applications.
- Repository content needs to be assigned the rdf:type property "indexible" in order to be indexed.
Triplestore
- An external triplestore can be used to index the RDF triples of content managed by Fedora.
- Any triplestore that supports SPARQL-update can be used; Fuseki and Sesame have been tested.
External Search
- An external search application can be used to perform more complex search queries on repository content.
- Any search application that supports SPARQL-update can be used; Solr has been tested.
Authorization
Pluggable authorization framework.
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