This is an example fcrepo 4.x <=> solr indexer that listens to the Fedora JMS topic and indexes things into Solr accordingly. It is built relying heavily on Spring machinery, including:

• spring-lang
• spring-jms
• activemq-spring (?)

Running the indexer

Beats me. I assume we should have a stand-alone mode that implements a main() method, but probably should also do something so it runs inside e.g. an OSGi container or Tomcat itself.

Configuring the indexer

There is an example Spring configuration in the tests, but it goes something like this:

 <bean class="org.apache.solr.client.solrj.impl.HttpSolrServer">
    <constructor-arg value="http://localhost:8983/solr" />

  </bean>

  <bean class="org.fcrepo.indexer.RepositoryProfile">
    <property name="repositoryURL" value="http://localhost:${test.port:8080}/rest" />
  </bean>

  <lang:jruby id="rubyScriptClass" script-interfaces="org.fcrepo.indexer.solr.ScriptIndexer" script-source="classpath:demo_ruby_solr_indexer.rb" />

  <!-- this is the Message Driven POJO (MDP) -->
  <bean id="solrIndexer" class="org.fcrepo.indexer.solr.ScriptingSolrIndexer" />

  <bean id="destination" class="org.apache.activemq.command.ActiveMQTopic">
    <constructor-arg value="fedora" />
  </bean>

  <!-- and this is the message listener container -->
  <bean id="jmsContainer" class="org.springframework.jms.listener.DefaultMessageListenerContainer">
    <property name="connectionFactory" ref="connectionFactory"/>
    <property name="destination" ref="destination"/>
    <property name="messageListener" ref="solrIndexer" />
    <property name="sessionTransacted" value="true"/>
  </bean>

The magic is in the jmsContainer bean. It will listen to the destination for messages, and pass them onto our messageListener. In this case, the messageListener is a Ruby script that is loaded in the lang:jruby construct.

The messageListener class implements the ScriptingSolrIndexer interface (which implements the javax.jms.MessageListener interface). It should respond to an onMessage call by taking the message and indexing the object appropriately.