First, we must declare a persistent class as indexable. This is done by annotating the class with @Indexed (all entities not annotated with @Indexed will be ignored by the indexing process):

@Entity
@Indexed(index="indexes/essays")
public class Essay {
    ...
}

The index attribute tells Hibernate what the Lucene directory name is (usually a directory on your file system). It is recommended to define a base directory for all Lucene indexes using the hibernate.search.default.indexBase property in your configuration file. Alternatively you can specify a base directory per indexed entity by specifying hibernate.search.<index>.indexBase, where <index> is the fully qualified classname of the indexed entity. Each entity instance will be represented by a Lucene Document inside the given index (aka Directory).

For each property (or attribute) of your entity, you have the ability to describe how it will be indexed. The default (no annotation present) means that the property is completely ignored by the indexing process. @Field does declare a property as indexed. When indexing an element to a Lucene document you can specify how it is indexed:

Whether or not you want to store the original data in the index depends on how you wish to use the index query result. For a regular Hibernate Search usage storing is not necessary. However you might want to store some fields to subsequently project them (see Section 5.1.2.5, “Projection” for more information).

Whether or not you want to tokenize a property depends on whether you wish to search the element as is, or by the words it contains. It make sense to tokenize a text field, but tokenizing a date field probably not. Note that fields used for sorting must not be tokenized.

Finally, the id property of an entity is a special property used by Hibernate Search to ensure index unicity of a given entity. By design, an id has to be stored and must not be tokenized. To mark a property as index id, use the @DocumentId annotation. If you are using Hibernate Annotations and you have specified @Id you can omit @DocumentId. The chosen entity id will also be used as document id.

@Entity
@Indexed(index="indexes/essays")
public class Essay {
    ...

    @Id
    @DocumentId
    public Long getId() { return id; }

    @Field(name="Abstract", index=Index.TOKENIZED, store=Store.YES)
    public String getSummary() { return summary; }

    @Lob
    @Field(index=Index.TOKENIZED)
    public String getText() { return text; }
}

The above annotations define an index with three fields: id , Abstract and text . Note that by default the field name is decapitalized, following the JavaBean specification

Sometimes one has to map a property multiple times per index, with slightly different indexing strategies. For example, sorting a query by field requires the field to be UN_TOKENIZED. If one wants to search by words in this property and still sort it, one need to index it twice - once tokenized and once untokenized. @Fields allows to achieve this goal.

@Entity
@Indexed(index = "Book" )
public class Book {
    @Fields( {
            @Field(index = Index.TOKENIZED),
            @Field(name = "summary_forSort", index = Index.UN_TOKENIZED, store = Store.YES)
            } )
    public String getSummary() {
        return summary;
    }

    ...
}

The field summary is indexed twice, once as summary in a tokenized way, and once as summary_forSort in an untokenized way. @Field supports 2 attributes useful when @Fields is used:

See below for more information about analyzers and field bridges.

Associated objects as well as embedded objects can be indexed as part of the root entity index. This is useful if you expect to search a given entity based on properties of associated objects. In the following example the aim is to return places where the associated city is Atlanta (In the Lucene query parser language, it would translate into address.city:Atlanta).

@Entity
@Indexed
public class Place {
    @Id
    @GeneratedValue
    @DocumentId
    private Long id;

    @Field( index = Index.TOKENIZED )
    private String name;

    @OneToOne( cascade = { CascadeType.PERSIST, CascadeType.REMOVE } )
    @IndexedEmbedded
    private Address address;
    ....
}

@Entity
public class Address {
    @Id
    @GeneratedValue
    private Long id;

    @Field(index=Index.TOKENIZED)
    private String street;

    @Field(index=Index.TOKENIZED)
    private String city;

    @ContainedIn
    @OneToMany(mappedBy="address")
    private Set<Place> places;
    ...
}

In this example, the place fields will be indexed in the Place index. The Place index documents will also contain the fields address.id, address.street, and address.city which you will be able to query. This is enabled by the @IndexedEmbedded annotation.

Be careful. Because the data is denormalized in the Lucene index when using the @IndexedEmbedded technique, Hibernate Search needs to be aware of any change in the Place object and any change in the Address object to keep the index up to date. To make sure the Place Lucene document is updated when it's Address changes, you need to mark the other side of the bidirectional relationship with @ContainedIn.

@ContainedIn is only useful on associations pointing to entities as opposed to embedded (collection of) objects.

Let's make our example a bit more complex:

@Entity
@Indexed
public class Place {
    @Id
    @GeneratedValue
    @DocumentId
    private Long id;

    @Field( index = Index.TOKENIZED )
    private String name;

    @OneToOne( cascade = { CascadeType.PERSIST, CascadeType.REMOVE } )
    @IndexedEmbedded
    private Address address;
    ....
}

@Entity
public class Address {
    @Id
    @GeneratedValue
    private Long id;

    @Field(index=Index.TOKENIZED)
    private String street;

    @Field(index=Index.TOKENIZED)
    private String city;

    @IndexedEmbedded(depth = 1, prefix = "ownedBy_")
    private Owner ownedBy;

    @ContainedIn
    @OneToMany(mappedBy="address")
    private Set<Place> places;
    ...
}

@Embeddable
public class Owner {
    @Field(index = Index.TOKENIZED)
    private String name;
   ...
}

Any @*ToMany, @*ToOne and @Embedded attribute can be annotated with @IndexedEmbedded. The attributes of the associated class will then be added to the main entity index. In the previous example, the index will contain the following fields

The default prefix is propertyName., following the traditional object navigation convention. You can override it using the prefix attribute as it is shown on the ownedBy property.

The depth property is necessary when the object graph contains a cyclic dependency of classes (not instances). For example, if Owner points to Place. Hibernate Search will stop including Indexed embedded attributes after reaching the expected depth (or the object graph boundaries are reached). A class having a self reference is an example of cyclic dependency. In our example, because depth is set to 1, any @IndexedEmbedded attribute in Owner (if any) will be ignored.

Using @IndexedEmbedded for object associations allows you to express queries such as:

In a way it mimics the relational join operation in a more efficient way (at the cost of data duplication). Remember that, out of the box, Lucene indexes have no notion of association, the join operation is simply non-existent. It might help to keep the relational model normalized while benefiting from the full text index speed and feature richness.

When @IndexedEmbedded points to an entity, the association has to be directional and the other side has to be annotated @ContainedIn (as seen in the previous example). If not, Hibernate Search has no way to update the root index when the associated entity is updated (in our example, a Place index document has to be updated when the associated Address instance is updated).

Sometimes, the object type annotated by @IndexedEmbedded is not the object type targeted by Hibernate and Hibernate Search. This is especially the case when interfaces are used in lieu of their implementation. For this reason you can override the object type targeted by Hibernate Search using the targetElement parameter.

@Entity
@Indexed
public class Address {
    @Id
    @GeneratedValue
    @DocumentId
    private Long id;

    @Field(index= Index.TOKENIZED)
    private String street;

    @IndexedEmbedded(depth = 1, prefix = "ownedBy_", targetElement = Owner.class)
    @Target(Owner.class)
    private Person ownedBy;


    ...
}

@Embeddable
public class Owner implements Person { ... }

Lucene has the notion of boost factor. It's a way to give more weight to a field or to an indexed element over others during the indexation process. You can use @Boost at the @Field, method or class level.

@Entity
@Indexed(index="indexes/essays")
@Boost(1.7f)
public class Essay {
    ...

    @Id
    @DocumentId
    public Long getId() { return id; }

    @Field(name="Abstract", index=Index.TOKENIZED, store=Store.YES, boost=@Boost(2f))
    @Boost(1.5f)
    public String getSummary() { return summary; }

    @Lob
    @Field(index=Index.TOKENIZED, boost=@Boost(1.2f))
    public String getText() { return text; }

    @Field
    public String getISBN() { return isbn; }

}        

In our example, Essay's probability to reach the top of the search list will be multiplied by 1.7. The summary field will be 3.0 (2 * 1.5 - @Field.boost and @Boost on a property are cumulative) more important than the isbn field. The text field will be 1.2 times more important than the isbn field. Note that this explanation in strictest terms is actually wrong, but it is simple and close enough to reality for all practical purposes. Please check the Lucene documentation or the excellent Lucene In Action from Otis Gospodnetic and Erik Hatcher.

The default analyzer class used to index tokenized fields is configurable through the hibernate.search.analyzer property. The default value for this property is org.apache.lucene.analysis.standard.StandardAnalyzer.

You can also define the analyzer class per entity, property and even per @Field (useful when multiple fields are indexed from a single property).

@Entity
@Indexed
@Analyzer(impl = EntityAnalyzer.class)
public class MyEntity {
    @Id
    @GeneratedValue
    @DocumentId
    private Integer id;

    @Field(index = Index.TOKENIZED)
    private String name;

    @Field(index = Index.TOKENIZED)
    @Analyzer(impl = PropertyAnalyzer.class)
    private String summary;

    @Field(index = Index.TOKENIZED, analyzer = @Analyzer(impl = FieldAnalyzer.class)
    private String body;

    ...
}

In this example, EntityAnalyzer is used to index all tokenized properties (eg. name), except summary and body which are indexed with PropertyAnalyzer and FieldAnalyzer respectively.

@AnalyzerDef(name="customanalyzer",
        tokenizer = @TokenizerDef(factory = StandardTokenizerFactory.class),
        filters = {
                @TokenFilterDef(factory = ISOLatin1AccentFilterFactory.class),
                @TokenFilterDef(factory = LowerCaseFilterFactory.class),
                @TokenFilterDef(factory = StopFilterFactory.class, params = {
                    @Parameter(name="words", value= "org/hibernate/search/test/analyzer/solr/stoplist.properties" ),
                    @Parameter(name="ignoreCase", value="true")
                })
})
public class Team {
    ...
}

@Entity
@Indexed
@AnalyzerDef(name="customanalyzer", ... )
public class Team {
    @Id
    @DocumentId
    @GeneratedValue
    private Integer id;

    @Field
    private String name;

    @Field
    private String location;

    @Field @Analyzer(definition = "customanalyzer")
    private String description;
}

Analyzer analyzer = fullTextSession.getSearchFactory().getAnalyzer("customanalyzer");

@Entity
@Indexed
@AnalyzerDefs({
  @AnalyzerDef(name = "en",
    tokenizer = @TokenizerDef(factory = StandardTokenizerFactory.class),
    filters = {
      @TokenFilterDef(factory = LowerCaseFilterFactory.class),
      @TokenFilterDef(factory = EnglishPorterFilterFactory.class
      )
    }),
  @AnalyzerDef(name = "de",
    tokenizer = @TokenizerDef(factory = StandardTokenizerFactory.class),
    filters = {
      @TokenFilterDef(factory = LowerCaseFilterFactory.class),
      @TokenFilterDef(factory = GermanStemFilterFactory.class)
    })
})
public class BlogEntry {

    @Id
    @GeneratedValue
    @DocumentId
    private Integer id;

    @Field
    @AnalyzerDiscriminator(impl = LanguageDiscriminator.class)
    private String language;
    
    @Field
    private String text;
    
    private Set<BlogEntry> references;

    // standard getter/setter
    ...
}

public class LanguageDiscriminator implements Discriminator {

    public String getAnanyzerDefinitionName(Object value, Object entity, String field) {
        if ( value == null || !( entity instanceof Article ) ) {
            return null;
        }
        return (String) value;
    }
}

org.apache.lucene.queryParser.QueryParser parser = new QueryParser(
    "title", 
    fullTextSession.getSearchFactory().getAnalyzer( Song.class )
);

org.apache.lucene.search.Query luceneQuery = 
    parser.parse( "title:sky Or title_stemmed:diamond" );

org.hibernate.Query fullTextQuery = 
    fullTextSession.createFullTextQuery( luceneQuery, Song.class );

List result = fullTextQuery.list(); //return a list of managed objects