4.4. Boosting
Lucene uses boosting to attach more importance to specific fields or documents over others. Lucene differentiates between index and search-time boosting.
4.4.1. Static Index Time Boosting
The
@Boost annotation is used to define a static boost value for an indexed class or property. This annotation can be used within @Field, or can be specified directly on the method or class level.
In the following example:
- the probability of Essay reaching the top of the search list will be multiplied by 1.7.
@Field.boostand@Booston a property are cumulative, therefore the summary field will be 3.0 (2 x 1.5), and more important than the ISBN field.- The text field is 1.2 times more important than the ISBN field.
Example 4.7. Different ways of using @Boost
@Indexed
@Boost(1.7f)
public class Essay {
...
@Field(name="Abstract", store=Store.YES, boost=@Boost(2f))
@Boost(1.5f)
public String getSummary() { return summary; }
@Field(boost=@Boost(1.2f))
public String getText() { return text; }
@Field
public String getISBN() { return isbn; }
}