Page History

*Available as of Camel 2.2

*

The *lucene* component is based on the Apache Lucene project. Apache Lucene is a powerful high-performance, full-featured text search engine library written entirely in Java. For more details about Lucene, please see the following

 links 
    * [http://lucene.apache.org/java/docs/

]
    * [http://lucene.apache.org/java/docs/features.html

]

The lucene component in camel facilitates integration and utilization of Lucene endpoints in enterprise integration patterns and scenarios. The lucene component does the following

* builds a searchable index of documents when payloads are sent to the Lucene Endpoint

* facilitates performing of indexed searches in Camel

  
This component only supports producer endpoints.

 

Maven users will need to add the following dependency to their {{pom.xml}} for this component:

}}

h3. Insert Options
{div:class=confluenceTableSmall}
|| Name || Default Value || Description ||
| {{analyzer}} | {{StandardAnalyzer}} | An Analyzer builds TokenStreams, which analyze text. It thus represents a policy for extracting index terms from text. The value for analyzer can be any class that extends the abstract class org.apache.lucene.analysis.Analyzer. Lucene also offers a rich set of analyzers out of the

 box |
| {{indexDir}} | {{./indexDirectory

}} | A file system directory in which index files are created upon analysis of the document by the specified

 analyzer |
| {{srcDir}} | {{null}} | An optional directory containing files to be used to be analyzed and added to the index at producer startup. |
{div}

h3. Query Options
{div:class=confluenceTableSmall}
|| Name || Default Value || Description ||
| {{analyzer}} | {{StandardAnalyzer}} | An Analyzer builds TokenStreams, which analyze text. It thus represents a policy for extracting index terms from text. The value for analyzer can be any class that extends the abstract class org.apache.lucene.analysis.Analyzer. Lucene also offers a rich set of analyzers out of the

 box |
| {{indexDir}} | {{./indexDirectory

}} | A file system directory in which index files are created upon analysis of the document by the specified

 analyzer |
| {{maxHits}} | {{10}} | An integer value that limits the result set of the search operation |
{div}

h3. Sending/Receiving Messages to/from the cache

h4. Message Headers
{div:class=confluenceTableSmall}
|| Header || Description ||
| {{QUERY}} | The Lucene Query to performed on the index. The query may include wildcards and phrases |
{div}

h4. Lucene Producers 
This component supports 2 producer endpoints.
* *insert* - The insert producer builds a searchable index by analyzing the body in incoming exchanges and associating it with a token ("content"). 
* *query* - The query producer performs searches on a pre-created index. The query uses the searchable index to perform score & relevance based searches. Queries are sent via the incoming exchange contains a header property name called 'QUERY'. The value of the header property 'QUERY' is a Lucene Query. For more details on how to create Lucene Queries check out [http://lucene.apache.org/java/3_0_0/queryparsersyntax.html

{code}

h4. Example 2: Loading properties into the JNDI registry in the Camel Context

 
{code

}
@Override
protected JndiRegistry createRegistry() throws Exception {
  JndiRegistry registry =
         new JndiRegistry(createJndiContext());
  registry.bind("whitespace", new File("./whitespaceIndexDir"));
  registry.bind("load_dir",
        new File("src/test/resources/sources"));
  registry.bind("whitespaceAnalyzer",
        new WhitespaceAnalyzer());
  return registry;
}
...
CamelContext context = new DefaultCamelContext(createRegistry());

{code}

h4. Example 2: Performing searches using a Query Producer

{code

}
RouteBuilder builder = new RouteBuilder() {
    public void configure() {
       from("direct:start").
          setHeader("QUERY", constant("Seinfeld")).
          to("lucene:searchIndex:query?analyzer=#whitespaceAnalyzer&indexDir=#whitespace&maxHits=20").
          to("direct:next");
                
       from("direct:next").process(new Processor() {
          public void process(Exchange exchange) throws Exception {
             Hits hits = exchange.getIn().getBody(Hits.class);
             printResults(hits);
          }

          private void printResults(Hits hits) {
              LOG.debug("Number of hits: " + hits.getNumberOfHits());
              for (int i = 0; i < hits.getNumberOfHits(); i++) {
                 LOG.debug("Hit " + i + " Index Location:" + hits.getHit().get(i).getHitLocation());
                 LOG.debug("Hit " + i + " Score:" + hits.getHit().get(i).getScore());
                 LOG.debug("Hit " + i + " Data:" + hits.getHit().get(i).getData());
              }
           }
       }).to("mock:searchResult");
   }
};

{code}

h4. Example 3: Performing searches using a Query Processor

 
{code

}
RouteBuilder builder = new RouteBuilder() {
    public void configure() {            
        try {
            from("direct:start").
                setHeader("QUERY", constant("Rodney Dangerfield")).
                process(new LuceneQueryProcessor("target/stdindexDir", analyzer, null, 20)).
                to("direct:next");
        } catch (Exception e) {
            e.printStackTrace();
        }
                
        from("direct:next").process(new Processor() {
            public void process(Exchange exchange) throws Exception {
                Hits hits = exchange.getIn().getBody(Hits.class);
                printResults(hits);
            }
                    
            private void printResults(Hits hits) {
                LOG.debug("Number of hits: " + hits.getNumberOfHits());
                for (int i = 0; i < hits.getNumberOfHits(); i++) {
                    LOG.debug("Hit " + i + " Index Location:" + hits.getHit().get(i).getHitLocation());
                    LOG.debug("Hit " + i + " Score:" + hits.getHit().get(i).getScore());
                    LOG.debug("Hit " + i + " Data:" + hits.getHit().get(i).getData());
                }
            }
       }).to("mock:searchResult");
   }
};
{code}