grouping logic: A and (B or C) with search API

bcn · **Joined:** Sun Sep 18, 2011 4:44 pm **Posts:** 22

How can I use the Hibernate search API to implement a logic like A and (B or C)?
Somehow BooleanJunction is missing a parenthesis method.

Thanks in advance

sanne.grinovero · **Posted:** Mon Sep 26, 2011 10:04 am

Hi,
when using the Boolean queries you can combine several queries, like with

Code:

orderQB.bool()
  .must(
      orderQB.range()
           .onField(“price”).above(100).excludeLimit().createQuery() )
  .must(
      orderQB.keyword(“user.city”).matching(“Paris”)
      .createQuery()
).createQuery();

Now if you need to nest them, each keyword query from this example can be a boolean query in itself.

bcn · **Joined:** Sun Sep 18, 2011 4:44 pm **Posts:** 22

Still, I am unable to achieve the desired logic. Maybe it is a Lucene feature and not Hibernate Search specific.
Say, a, b, c are the resp. queries.
Then
qb.bool().must(a).must(qb.bool().should(b).should(c))
includes results for which neither b nor c is true. What I want is that either b or c must be true.

Thanks

sanne.grinovero · **Posted:** Mon Sep 26, 2011 10:55 am

Quote:

What I want is that either b or c must be true.

you mean "either or but not both" ?

bcn · **Joined:** Sun Sep 18, 2011 4:44 pm **Posts:** 22

No, I mean either b or c or both.
Just the normal boolean logic.

There seems to be no way to achieve the parenthesis logic with the API. You can only chain queries,
but should(b).should(c) still allows other elements in the result list (I guess with a lower score,
but I want to exclude them completely).

Thanks

sanne.grinovero · **Posted:** Tue Sep 27, 2011 5:49 pm

Actually if you write something like

Quote:

should(b).should(c)

it's going to contain exclusively documents matching b or c or both, and nothing else.

If you see different values being returned you might have a problem with the chosen Analyzer.
Can you provide a test ?

You could also use Projections on FullTextQuery.EXPLANATION to have the query engine explain why it's returning each result.

bcn · **Joined:** Sun Sep 18, 2011 4:44 pm **Posts:** 22

The query I use has
bj = bj.should(qb.keyword().wildcard().onField("field1")
.matching(estabName + "*").createQuery());
bj = bj.should(qb.keyword().onField("field1")
.matching(estabName).createQuery());
The field is annotated like
@Field(index = Index.YES, analyze = Analyze.YES, store = Store.NO)

(I omit other must junctions.)

Nothing special. But when I search with some words "XXX YYY", the result contains also fields which do not contain any of the words or start with them.
When I get some time, I will check with EXPLANATION.

Thanks