Hibernate Search and Lucene

ben503 · **Joined:** Thu Sep 11, 2008 5:22 pm **Posts:** 3

Hello,

I am working on a Seam application that uses Hibernate Search to build and search Lucene indexes. I have put Hibernate Search annotations all over my JPA Entities, and the Hibernate Search is building searchable indexes. Perfect.

However, I need to create an index that I do not believe can be created via Hibernate Search. Let me give an example. Consider the following object:

Code:

@Entity
@Indexed
public class Person implements HasFavoriteNumber {

  @Field(index = Index.UN_TOKENIZED ) private String id;
  @Field(index = Index.TOKENIZED ) private String name;
  @Field(index = Index.UN_TOKENIZED ) private int favoriteNumber; // a number from 1 to 10

  //getters and setters follow..
}

Let's pretend that I would like to create a Lucene index that stores the spelling of the person's favorite number: i.e. if the person's favorite number is 7, I want an index called favoriteNumberInEnglish that would contain the value "seven" for this Person. I have created a class (FavoriteNumberInEnglishListener) that implements PostInsertEventListener, PostUpdateEventListener PostDeleteEventListener. Hibernate calls my class after update. However, it appears that Hibernate Search has not indexed the Person -- when I create Query object and search by ID, I get zero hits:

Code:

//omitting insert and delete, since they're very similar to update, but they are there in my actual code

public class FavoriteNumberInEnglishListener implements PostUpdateListener {

  public void onPostUpdate(PostUpdateEvent event) {
    Object o = event.getEntity();
    if( o instanceof HasFavoriteNumber ) {
      HasFavoriteNumber hasFavoriteNumber = ( HasFavoriteNumber ) o;
      try {
        Directory d = FSDirectory.getDirectory(DIRECTORY);
        IndexReader ir = indexReader.open(d);
        QueryParser parser = new QueryParser("id", new StandardAnalyzer());
        Query q = parser.parse(hasFavoriteNumber.getId());
        Hits hits = new IndexSearcher(ir).search(q); // this always has zero results
        if( hits.length() == 1 ) { // never returns true, as hits.length() is always zero
          Document doc = hits.doc(0);
          doc.add( new Field("favoriteNumberInEnglish", hasFavoriteNumber.getFavoriteNumber(), Field.Store.YES, Field.Index.UN_TOKENIZED));
           // and then write the document using an IndexWriter
        }
      }
      catch( Exception e ) {}
    }
  }

I thought that perhaps the problem was that Hibernate was calling my Listener before it was calling FullTextIndexEventListener, so I made my listener subclass FullTextIndexEventListener and put a call to the superclass as the first line in onPostUpdate, but I still found zero hits.

Any ideas what I'm doing wrong? I get the feeling my approach may be completely off -- if there is a better way for me to do this, I can change my approach.

Thank you in advance for any assistance.[/code]

sanne.grinovero · **Posted:** Sat Sep 13, 2008 8:39 am

I don't understand why you are implementing an eventlistener.
If you only want to code the favorite number from int 7 to String "seven"
you need a StringBridge and let Search do the work for you.

http://www.hibernate.org/hib_docs/search/reference/en/html_single/#d0e1622

ben503 · **Joined:** Thu Sep 11, 2008 5:22 pm **Posts:** 3

Ah, that makes sense. That will work well.

One other question: let's assume that I have made the following changes:

Code:

@Entity
@Indexed
public class PersonAttribute {
  @Field private String attributeName;
  @Field private String attributeValue;
}

@Entity
@Indexed
public class Person {
  @Field(index = Index.UN_TOKENIZED ) private String id;
  @Field(index = Index.TOKENIZED ) private String name;
  @Field(index = Index.UN_TOKENIZED )  public int favoriteNumber;
  private Set<PersonAttribute> attributes = new HashSet<PersonAttribute>();
}

We do something similar to this, to allow for flexibility in our model across multiple installations. How could I create indexes on the PersonAttribute objects? For example, if I create a person named Fred, whose attributes Collection contains one PersonAttribute with attributeName of "favoriteColor" and attribute value of "green", I would like to be able to write the query +favoriteColor:green and be returned Fred. Is there any way to do this? I don't think that @IndexEmbeded and @ContainedIn will work here, will it?