Chapter 215. Lucene Component Available as of Camel version 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: <dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-lucene</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency> 215.1. URI format lucene:searcherName:insert[?options] lucene:searcherName:query[?options] You can append query options to the URI in the following format, ?option=value&option=value&... 215.2. Insert Options The Lucene component supports 2 options, which are listed below. Name Description Default Type config (advanced) To use a shared lucene configuration LuceneConfiguration resolveProperty Placeholders (advanced) Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. true boolean The Lucene endpoint is configured using URI syntax: with the following path and query parameters: 215.2.1. Path Parameters (2 parameters): Name Description Default Type host Required The URL to the lucene server String operation Required Operation to do such as insert or query. LuceneOperation 215.2.2. Query Parameters (5 parameters): Name Description Default Type analyzer (producer) 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 Analyzer indexDir (producer) A file system directory in which index files are created upon analysis of the document by the specified analyzer File maxHits (producer) An integer value that limits the result set of the search operation int srcDir (producer) An optional directory containing files to be used to be analyzed and added to the index at producer startup. File synchronous (advanced) Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). false boolean 215.3. Spring Boot Auto-Configuration The component supports 11 options, which are listed below. Name Description Default Type camel.component.lucene.config.analyzer 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 Analyzer camel.component.lucene.config.authority String camel.component.lucene.config.host The URL to the lucene server String camel.component.lucene.config.index-directory A file system directory in which index files are created upon analysis of the document by the specified analyzer File camel.component.lucene.config.lucene-version Version camel.component.lucene.config.max-hits An integer value that limits the result set of the search operation Integer camel.component.lucene.config.operation Operation to do such as insert or query. LuceneOperation camel.component.lucene.config.source-directory An optional directory containing files to be used to be analyzed and added to the index at producer startup. File camel.component.lucene.config.uri URI camel.component.lucene.enabled Enable lucene component true Boolean camel.component.lucene.resolve-property-placeholders Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. true Boolean 215.4. Sending/Receiving Messages to/from the cache 215.4.1. Message Headers Header Description QUERY The Lucene Query to performed on the index. The query may include wildcards and phrases RETURN_LUCENE_DOCS Camel 2.15: Set this header to true to include the actual Lucene documentation when returning hit information. 215.4.2. 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 215.4.3. Lucene Processor There is a processor called LuceneQueryProcessor available to perform queries against lucene without the need to create a producer. 215.5. Lucene Usage Samples 215.5.1. Example 1: Creating a Lucene index RouteBuilder builder = new RouteBuilder() { public void configure() { from("direct:start"). to("lucene:whitespaceQuotesIndex:insert? analyzer=#whitespaceAnalyzer&indexDir=#whitespace&srcDir=#load_dir"). to("mock:result"); } }; 215.5.2. Example 2: Loading properties into the JNDI registry in the Camel Context @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()); 215.5.3. Example 2: Performing searches using a Query Producer 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:"); from("direct:").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"); } }; 215.5.4. Example 3: Performing searches using a Query Processor 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:"); } catch (Exception e) { e.printStackTrace(); } from("direct:").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"); } };

Commands:
<dependency> <groupId>org.apache.camel</groupId> <artifactId>camel-lucene</artifactId> <version>x.x.x</version> <!-- use the same version as your Camel core version --> </dependency>
lucene:searcherName:insert[?options] lucene:searcherName:query[?options]
lucene:host:operation
RouteBuilder builder = new RouteBuilder() { public void configure() { from("direct:start"). to("lucene:whitespaceQuotesIndex:insert? analyzer=#whitespaceAnalyzer&indexDir=#whitespace&srcDir=#load_dir"). to("mock:result"); } };
@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());
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"); } };
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"); } };