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Using Apache Solr's boost query function with Spring in Java

I'm writing a Java application that is using Apache Solr to index and search through a list of articles. A requirement I am dealing with is that when a user searches for something, we are supplying a list of recommended related search terms, and the user has the option to include those extra terms in their search. The problem I'm having, however, is that we want the user's original search term to be prioritized, and results that match that should appear before results that only match related terms.
My research suggests that Solr's boost function is the solution for this, but I'm having some trouble getting it to work with Spring. The code all runs fine and I get my search results as expected, but the boost function doesn't seem to actually be re-ordering my searches at all. For example, I'm trying to do something like this:
Query query = new SimpleQuery();
Criteria searchCriteria = Criteria.where("title").contains("A").boost((float) 2);
Criteria extraCriteria = Criteria.where("title").contains("B").boost((float) 1);
query.addCriteria(searchCriteria.or(extraCriteria));
In this example I would be searching for any document whose title contains "A" or "B", but I want to boost results that match "A" to the top of the list.
I've also tried using the Extended DisMax Query Parser with a different syntax to achieve the same result, with similar lack of success. To follow the same example pattern, I'm trying to use the expression criteria as follows:
Query query = new SimpleQuery();
Criteria searchCriteria = Criteria.where("title").expression("A^2.0 OR B^1.0");
query.setDefType("edismax");
query.addCriteria(searchCriteria);
Again I would expect this to return documents with titles matching "A" or "B" but boost results matching "A", and again it simply doesn't seem to actually affect the ordering of my results at all.

Okay, I figured out the problem here. Elsewhere in the code someone else had added this snippet:
query.setPageRequest(pageable);
This was done to support pagination of the search results, but the pageable object ALSO contained some sort orders that looks like they got added to the query as part of the .setPageRequest method. Something to look out for in the future, it looks like sorts override boosting when working with Spring Solr queries in this scenario.

Querying Hibernate Search with a logic pattern

I'm integrating Hibernate Search in my project and at the moment it works fine.
Now I want to refine my search in this way: basically I'd like to pass, as a user, a query like term1 AND term2 OR term3 and so on. The number of terms could be different of course.
So my idea is to build a proper search with logical operators to help the users to find what they want to.

You have to separate your conditions which are using AND and OR by using ().
e.g.
(term1 AND term2) OR term3
If you are again wanted to use some term the it should be like ((term1 AND term2) OR term3) AND term4 like this.....

You can use this stackoverflow answer if you have one entity.
You can use a boolean query like :
Query luceneQuery = b.bool()
.must(b.keyword().onField("fieldName").matching("term1").createQuery())
.must(b.keyword().onField("fieldName").matching("term2").createQuery())
.should(b.keyword().onField("fieldName").matching("term3").createQuery())
.except(b.keyword().onField("fieldName").matching("term4").createQuery())
.createQuery();
must : the query must much this term (like AND).
should : the query should this query (like OR).
except : to exclude the document that contains this term (like NOT).

IN Equivalent Query In Solr and Solrj

I am using solr5.0.0. I would like to know the equivalent query for
IN in solr or solrj.
If I need to query products of different brands, I can use IN clause. If I have brands like dell, sony, samsung. I need to find the product with these brands using Solr and in Java Solrj.
Now I am using this code in Solrj
qry.addFilterQuery("brand:dell OR brand:sony OR brand:samsung");
I know that I can use OR here, but need to know about IN in Solr. And the performance of OR.

As you can read in Solr's wiki about its' query syntax, Solr uses per default a superset of Lucene's Query parser. As you can see when reading both documents, something like IN does not exist. But you can get shorter than the example query you presented.
In case that your default operator is OR you can leave it out from the query. In addition you can make use of Field Grouping.
qry.addFilterQuery("brand:(dell sony samsung)");
In case OR is not your default operator or you are not sure about this, you can employ Local Parameters for the filter query so that OR is enforced. Afterwards you can again make use of Field Grouping.
qry.addFilterQuery("{!q.op=OR}brand:(dell sony samsung)");
Keep in mind that you need to surround a phrase with " to keep the words together
qry.addFilterQuery("{!q.op=OR}brand:(dell sony samsung \"packard bell\")");

Sort the values by Date in mongodb

I am new to mongodb and I am trying to sort all my rows by date. I have records from mixed sources and I trying to sort it separately. I didn't update the dateCreated while writing into db for some records. Later I found and I added dateCreated to all my records in the db. Say I have total of 4000 records, first 1000 I don't have dateCreated. Latest 3000 has that column. Here I am trying to get the last Updated record using dateCreated column. Here is my code.
db.person.find({"source":"Naukri"}&{dateCreated:{$exists:true}}).sort({dateCreated: 1}).limit(10)
This code retruns me some results (from that 1000 records) where I can't see that dateCreated column at all. Moreover if I change (-1) here {dateCreated: -1} I am getting results from some other source, but not Naukri.
So I need help this cases,
How do I sort by dateCreated to get the latest updated record and by sources also.
I am using Java API to get the records from Mongo. I'd be grateful if someone helps me to find how I will use the same query with java also.
Hope my question is clear. Thanks in advance.

From the documentation you will (and you will, won't you - nod yes) read, you will find that the first argument to the find command you are using is what is called a query document. In this document you are specifying a list of fields and conditions, "comma" separated, which is the equivalent of an and condition in declarative syntax such as SQL.
The problem with your query is it was not valid, and did not match anything. The correct syntax would be as follows:
db.person.find({"source":"Naukri", dateCreated:{$exists:true}})
.sort({dateCreated: -1})
.limit(10)
So now this will filter by the value provided for "source" and where the "dateCreated" field exists, meaning it is there and it contains something.
I recommend looking at the links below, the first of the two concerned with structuring mongoDB queries and the find method and it's arguments. All of the functionality translates to every language implementation.
As for the Java API and how to use, there are different methods depending on which you are comfortable with. The API provides a BasicDBObject class which is more or less equivalent to the JSON document notation, and is sort of a hashmap concept. For something a bit more along the lines of the shell methods and a helper to be a little more like some of the dynamic languages approach, there is the QueryBuilder class which the last two links give example and information on. These allow chaining to make your query more readable.
There are many examples on Stack Overflow alone. I suggest you take a look.
http://docs.mongodb.org/manual/tutorial/query-documents/
http://docs.mongodb.org/manual/reference/method/db.collection.find/
How to do this MongoDB query using java?
http://api.mongodb.org/java/2.2/com/mongodb/QueryBuilder.html

Your query is not correct.Update it as follows :
db.person.find({"source":"Naukri", dateCreated:{$exists:true}}).sort({dateCreated: 1}).limit(10)
In Java, you can do it as follows :
Mongo mongo = ...
DB db = mongo.getDB("yourDbName");
DBCollection coll = db.getCollection("person");
DBObject query = new BasicDBObject();
query.put("source", "Naukri");
query.put("dateCreated", new BasicDBObject($exists : true));
DBCursor cur = coll.find(query).sort(new BasicDBObject("dateCreated", 1)).limit(10);
while(cur.hasNext()) {
DBObject obj = cur.next();
// Get data from the result object here
}

GAE - Java - Best way to do a query filter "LIKE"

In my GAE Datastore I have "Person" Entity with name, surname and country
I need to do a query like
"SELECT * FROM Country WHERE name LIKE '%spa%'"
This answer offers a solution like this:
Query query = new Query("Person");
query.addFilter("name", FilterOperator.GREATER_THAN_OR_EQUAL, "pe");
query.addFilter("name", FilterOperator.LESS_THAN, "pe"+ "\uFFFD");
But I don't have any success, always return 0 results... I'm missing something?
It seems that another alternative is useing the "Search API", but... How I migrate all my data of "Persons" in my Datastore to a new Document to do the search?
Any solutions?
Thanks

That answer is not the same as your question. The query they provide is a prefix query: ie all names that start with "pe". You seem to want a query for all names which contain "pe" anywhere, which is not possible for the reasons explained in the accepted answer to that question.
The Search API is indeed the answer to doing this, and the details of how to create documents to represent your datastore objects are contained in the link you posted. (Note this isn't a migration: your data should stay in the datastore, the Search API is a separate system used only for full-text search.)