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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 check outabout Lucene, please see the following links

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 when the payload header contains a QUERY.

This component only supports 2 producer endpoints and a query processor.

URI format

Code Block
lucene:searcherName:insert[?options] lucene:searcherName:query[?options]

You can append query options to the URI in the following format, ?option=value&option=value&...

Insert Options

Name	Default Value	Description
`maxElementsInMemory` `analyzer`	`1000`	The numer of elements that may be stored in the defined cache	`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.

Query Options

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
`memoryStoreEvictionPolicy`	`MemoryStoreEvictionPolicy.LFU`	The number of elements that may be stored in the defined cache. Options include MemoryStoreEvictionPolicy.LFU - Least frequently used MemoryStoreEvictionPolicy.LRU - Least recently used MemoryStoreEvictionPolicy.FIFO - first in first out, the oldest element by creation time
`overflowToDisk`	`true`	Specifies whether cache may overflow to disk
`eternal`	`false`	Sets whether elements are eternal. If eternal, timeouts are ignored and the element is never expired.
`timeToLiveSeconds`	`300`	The maximum time between creation time and when an element expires. Is only used if the element is not eternal
`timeToIdleSeconds`	`300`	The maximum amount of time between accesses before an element expires
`diskPersistent`	`true`	Whether the disk store persists between restarts of the Virtual Machine. The default value is false.
`diskExpiryThreadIntervalSeconds`	`120`	The number of seconds between runs of the disk expiry thread. The default value is 120 seconds

Sending/Receiving Messages to/from the cache

Message Headers

Header

Description

CACHE_OPERATION QUERY

The operation Lucene Query to be performed on the cacheindex. The valid options are

ADD
UPDATE
DELETE
DELETEALL

CACHE_KEY

The cache key used to store the Message in the cache. The cache key is optional if the CACHE_OPERATION is DELETEALL

Cache Producer

Sending data to the cache involves the ability to direct payloads in exchanges to be stored in a pre-existing or created-on- demand cache. The mechanics of doing this involve

setting the Message Exchange Headers shown above.
ensuring that the Message Exchange Body contains the message directed to the cache

Cache Consumer

Receiving data from the cache involves the ability of the CacheConsumer to listen on a pre-existing or created-on-demand Cache using an event Listener and receive automatic notifications when any cache activity take place (i.e ADD/UPDATE/DELETE/DELETEALL). Upon such an activity taking place

an exchange containing Message Exchange Headers and a Message Exchange Body containing the just added/updated payload is placed and sent.
in case of a DELETEALL operation, the Message Exchange Header CACHE_KEY and the Message Exchange Body are not populated.

Cache Processors

There are a set of nice processors with the ability to perform cache lookups and selectively replace payload content at the

body
token
xpath level

Cache Usage Samples

Example 1: Configuring the cache

query may include wildcards and phrases

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

Lucene Processor

There is a processor called LuceneQueryProcessor available to perform queries against lucene without the need to create a producer.

Lucene Usage Samples

Example 1: Creating a Lucene index

Code Block


RouteBuilder builder = new RouteBuilder() {
    public void configure() {

Code Block


from("cache://MyApplicationCache" +
          "?maxElementsInMemory=1000" + 
from("direct:start").
            "&memoryStoreEvictionPolicy=" +to("lucene:whitespaceQuotesIndex:insert?analyzer=#whitespaceAnalyzer&indexDir=#whitespace&srcDir=#load_dir").
           to("mock:result");
   "MemoryStoreEvictionPolicy.LFU" +
          "&overflowToDisk=true" + }
};

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

Code Block


@Override
protected JndiRegistry createRegistry() throws Exception {
  JndiRegistry registry =
          "&eternal=true" +new JndiRegistry(createJndiContext());
  registry.bind("whitespace", new       "&timeToLiveSeconds=300" + File("./whitespaceIndexDir"));
  registry.bind("load_dir",
        new  "&timeToIdleSeconds=true" +
  File("src/test/resources/sources"));
  registry.bind("whitespaceAnalyzer",
        "&diskPersistent=true" +new WhitespaceAnalyzer());
  return registry;
}
...
CamelContext context =     "&diskExpiryThreadIntervalSeconds=300")new DefaultCamelContext(createRegistry());

Example 2:

...

Performing searches using a Query Producer

Code Block

RouteBuilder builder = new RouteBuilder() {
    public void configure() {
       from("direct:start").
     .     setHeader("CACHE_OPERATIONQUERY", constant("ADDSeinfeld")).
      .setHeader("CACHE_KEY", constant("Ralph_Waldo_Emerson"))
    to("lucene:searchIndex:query?analyzer=#whitespaceAnalyzer&indexDir=#whitespace&maxHits=20").
          .to("cachedirect://TestCache1next");
     }
};

Example 2: Updating existing keys in a cache

Code Block


RouteBuilder builder = new RouteBuilder           
       from("direct:next").process(new Processor() {
          public void configureprocess(Exchange exchange) throws Exception {
            from("direct:start")
 Hits hits = exchange.getIn().getBody(Hits.class);
      .setHeader("CACHE_OPERATION", constant("UPDATE"))
       printResults(hits);
          }

      .setHeader("CACHE_KEY", constant("Ralph_Waldo_Emerson"))     private void printResults(Hits hits) {
     .to("cache://TestCache1")
   }
};

Example 3: Deleting existing keys in a cache

Code Block


RouteBuilder builder = new RouteBuilder() {
    public void configure() {
     from("direct:start")
     .setHeader("CACHE_OPERATION", constant("DELETE"))
     .setHeader("CACHE_KEY", constant("Ralph_Waldo_Emerson"))
     .to("cache://TestCache1")         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");
   }
};

Example

...

3: Performing searches using a Query Processor

Code Block

RouteBuilder builder = new RouteBuilder() {
    public void configure() {            
        try {
            from("direct:start").
             .   setHeader("CACHE_OPERATIONQUERY", constant("DELETEALLRodney Dangerfield")).
          .to      process(new LuceneQueryProcessor("cache:target//TestCache1");
    }
};

Example 5: Notifying any changes registering in a Cache to Processors and other Producers

Code Block


RouteBuilder builder = new RouteBuilder() {
stdindexDir", analyzer, null, 20)).
         public void configure() {
     fromto("cachedirect://TestCache1next");
     .process(new Processor(   } catch (Exception e) {
         public  void process(Exchange exchange) e.printStackTrace();
        }
        throws Exception {
      
     String operation = from(String) exchange.getIn().getHeader("CACHE_OPERATION");"direct:next").process(new Processor() {
           String keypublic =void process(String)Exchange exchange.getIn().getHeader("CACHE_KEY");
) throws Exception {
               Object Hits bodyhits = exchange.getIn().getBody(Hits.class);
            //   Do somethingprintResults(hits);
            } 

                    })
   } 
};

Example 6: Using Processors to selectively replace payload with cache values

Code Block


RouteBuilder builder = new RouteBuilder() {
   publicprivate void configureprintResults(Hits hits) {
     //Message Body Replacer
     from("cache://TestCache1")
     LOG.filterdebug(header("CACHE_KEY").isEqualTo("greeting"))
"Number of hits: " + hits.getNumberOfHits());
              .process(new CacheBasedMessageBodyReplacer("cache://TestCache1","farewell"))
     .to("direct:next");  

    //Message Token replacer
    from("cache://TestCache1")
    .filter(header("CACHE_KEY").isEqualTo("quote"))
    .process(new CacheBasedTokenReplacer("cache://TestCache1","novel","#novel#"))
    .process(new CacheBasedTokenReplacer("cache://TestCache1","author","#author#"))
    .process(new CacheBasedTokenReplacer("cache://TestCache1","number","#number#"))
    .to("direct:next");

    //Message XPath replacer
    from("cache://TestCache1").
    .filter(header("CACHE_KEY").isEqualTo("XML_FRAGMENT"))
    .process(new CacheBasedXPathReplacer("cache://TestCache1","book1","/books/book1"))
    .process (new CacheBasedXPathReplacer("cache://TestCache1","book2","/books/book2"))
    .to("direct:next  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");
   }
};

Child pages

Versions Compared

Old Version 1

New Version 2

Key

URI format

Insert Options

Query Options

Sending/Receiving Messages to/from the cache

Message Headers

Cache Producer

Cache Consumer

Cache Processors

Cache Usage Samples

Example 1: Configuring the cache

Lucene Producers

Lucene Processor

Lucene Usage Samples

Example 1: Creating a Lucene index

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

Example 2:

Performing searches using a Query Producer

Example 2: Updating existing keys in a cache

Example 3: Deleting existing keys in a cache

Example

3: Performing searches using a Query Processor

Example 5: Notifying any changes registering in a Cache to Processors and other Producers

Example 6: Using Processors to selectively replace payload with cache values