The SparqlIndexer listens to the repository generated JMS events and index records to a triplestore like Fuseki, Sesame etc. It implements the org.fcrepo.indexer.Indexer interface for the indexing functionalities, which consists of the methods to handle new/updated records and deleted records.
Once the SparqlIndexer index the records to the triplestore, we can use the triplestore to perform external SPARQL searchings for SPARQL Recipes.
Configuration
The SparqlIndexer is configured using Spring that can be done using Java bean setter methods. Here is a sample configuration fragment showing how to configure and use it:
<!-- Copy object RDF to a Fuseki triplestore using SPARQL Update -->
<bean id="sparqlUpdate" class="org.fcrepo.indexer.SparqlIndexer">
<!-- base URL for triplestore subjects, PID will be appended -->
<property name="prefix" value="http://localhost:${test.port:8080}/rest/objects/"/>
<property name="queryBase" value="http://localhost:3030/test/query"/>
<property name="updateBase" value="http://localhost:3030/test/update"/>
<property name="formUpdates">
<value type="java.lang.Boolean">false</value>
</property>
</bean>
<!-- Main indexer class that processes events, gets RDF from the repository and calls the workers -->
<bean id="indexerGroup" class="org.fcrepo.indexer.IndexerGroup">
<constructor-arg name="repositoryURL" value="http://${fcrepo.host:localhost}:${fcrepo.port:8080}${fcrepo.context:/}rest" />
<constructor-arg name="indexers">
<set>
...
<ref bean="sparqlUpdate"/>
...
</set>
</constructor-arg>
...
</bean>
