<dependency>
      <groupId>org.apache.cxf</groupId>
      <artifactId>cxf-rt-rs-extension-search</artifactId>
      <version>2.6.0</version>
   </dependency>

   <!-- If working with OData -->
   <!--
       <dependency>
            <groupId>org.apache.olingo</groupId>
            <artifactId>olingo-odata2-core-incubating</artifactId>
            <version>1.1.0</version> 
        </dependency>
   -->
 

@Path("books")
public class Books {

    private Map<Long, Book> books;
    @Context
    private SearchContext context;

    @GET
    public List<Book> getBook() {

        SearchCondition<Book> sc = searchContext.getCondition(Book.class);
        // SearchCondition#isMet method can also be used to build a list of matching beans

        // iterate over all the values in the books map and return a collection of matching beans
        List<Book> found = sc.findAll(books.values());
        return found;
    }
}

public class Book {

    private int id;
    private OwnerInfo ownerinfo;
    //setters and getters omitted for brewitybrevity
}

@Embeddable
public class OwnerInfo {

    private Address address;
    private Name name;
    //setters and getters omitted for brewitybrevity
}

@Embeddable
public class Name {

    private String name;
    //setters and getters omitted for brewitybrevity
}

public class Name {

    private String name;
    public Name() {
    } 
    public Name(String name) {
        this.name = name;
    }
    //setters and getters omitted for brewitybrevity
}

// ?_s="level=gt=10"
SearchCondition<SearchBean> sc = searchContext.getCondition(SearchBean.class);

Map\<, String\> fieldMap = new HashMap\<String, String\>();
fieldMap.put("level", "LEVEL_COLUMN");

SQLPrinterVisitor<SearchBean> visitor = new SQLPrinterVisitor<SearchBean>(fieldMap, "table", "LEVEL_COLUMN");
sc.accept(visitor);
assertEquals("SELECT LEVEL_COLUMN FROM table 
              WHERE LEVEL_COLUMN > '10'",
              visitor.getResultgetQuery());

// ?_s="name==ami*;level=gt=10"
SearchCondition<Book> sc = searchContext.getCondition(Book.class);
SQLPrinterVisitor<Book> visitor = new SQLPrinterVisitor<Book>("table");
sc.accept(visitor);
assertEquals("SELECT * FROM table 
              WHERE 
              name LIKE 'ami%' 
              AND 
              level > '10'",
              visitor.getResultgetQuery());

// ?_s="level=gt=10"
SearchCondition<Book> sc = searchContext.getCondition(Book.class);

Map<String, String> fieldMap = new HashMap<String, String>();
fieldMap.put("level", "LEVEL_COLUMN");

SQLPrinterVisitor<Book> visitor = new SQLPrinterVisitor<Book>(fieldMap, "table", "LEVEL_COLUMN");
sc.accept(visitor);
assertEquals("SELECT LEVEL_COLUMN FROM table 
              WHERE LEVEL_COLUMN > '10'",
              visitor.getResultgetQuery());

public class Book {

    private String title;
    private Date date;
    private OwnerInfo ownerinfo;
    //setters and getters omitted for brewitybrevity
}

@Embeddable
public class OwnerInfo {

    private Address address;
    private Name name;
    //setters and getters omitted for brewitybrevity
}

@Embeddable
public class Name {

    private String name;
    //setters and getters omitted for brewitybrevity
}

@Embeddable
public class Address {

    private String street;
    //setters and getters omitted for brewitybrevity
}

public static class BookInfo {
        private int id;
        private String title;

        public BookInfo() {
            
        }
        
        public BookInfo(Integer id, String title) {
            this.id = id;
            this.title = title;
        }
        //setters and getters omitted for brewitybrevity
 }

// actual application code:

SearchCondition<Book> sc = searchContext.getCondition(Book.class);
JPACriteriaQueryVisitor<Book, BookInfo> visitor = 
    new JPACriteriaQueryVisitor<Book, BookInfo>(entityManager, Book.class, BookInfo.class);
sc.accept(visitor);

List<SingularAttribute<Book, ?>> selections = new LinkedList<SingularAttribute<Book, ?>>();
// Book_ class is generated by JPA2 compiler
selections.add(Book_.id);
selections.add(Book_.title);

visitor.selectConstruct(selections);

TypedQuery<BookInfo> query = visitor.getQuery();

List<BookInfo> bookInfo = typedQuery.getResultList();
return bookInfo;

@Entity(name = "Book")
public class Book {

    private List<BookReview> reviews = new LinkedList<BookReview>();
    private List<String> authors = new LinkedList<String>();
    // other properties omitted

    @OneToMany
    public List<BookReview> getReviews() {
        return reviews;
    }

    public void setReviews(List<BookReview> reviews) {
        this.reviews = reviews;
    }

    @ElementCollection
    public List<String> getAuthors() {
        return authors;
    }

    public void setAuthors(List<String> authors) {
        this.authors = authors;
    }
}

@Entity
public class BookReview {
    private Review review;
    private List<String> authors = new LinkedList<String>();
    private Book book;
    // other properties omitted    

    public Review getReview() {
        return review;
    }

    public void setReview(Review review) {
        this.review = review;
    }

    @OneToOne
    public Book getBook() {
        return book;
    }

    public void setBook(Book book) {
        this.book = book;
    }

    @ElementCollection
    public List<String> getAuthors() {
        return authors;
    }

    public void setAuthors(List<String> authors) {
        this.authors = authors;
    }

    public static enum Review {
        GOOD,
        BAD
    }
}

SearchCondition<Book> filter = new FiqlParser<Book>(Book.class).parse("reviews.review==good;reviews.authors==Ted");
// in practice, map "reviews.review" to "review", "reviews.authors" to "reviewAuthor" 
// and have a simple query like "review==good;reviewAuthor==Ted" instead

SearchConditionVisitor<Book, TypedQuery<Book>> jpa = new JPATypedQueryVisitor<Book>(em, Book.class);
filter.accept(jpa);
TypedQuery<Book> query = jpa.getQuery();
return query.getResultList();

public class CustomSQLVisitor<T> extends AbstractSearchConditionVisitor<T, String> {

    private String tableName;
    private StringBuilder sb = new StringBuilder();

    public void visit(SearchCondition<T> sc) {
        
        if (sb == null) {
            sb = new StringBuilder();
            // start the expression as needed, example
            // sb.append("Select from ").append(tableName);
        }
        
        PrimitiveStatement statement = sc.getStatement();
        if (statement != null) {
                // ex "a > b"
                // use statement.getValue()
                // use statement.getConditionType() such as greaterThan, lessThan
                // use statement.getProperty();
                // to convert "a > b" into SQL expression
                sb.append(toSQL(statement));         
        } else {
            // composite expression, ex "a > b;c < d"
            for (SearchCondition<T> condition : sc.getSearchConditions()) {
                // pre-process, example sb.append("(");
                condition.accept(this);
                // post-process, example sb.append(")");
            }
        }
    }

    public String getQuery() {
        return sb.toString();
    }
}

public class CustomTypedVisitor<T> extends AbstractSearchConditionVisitor<T, Query> {

    private Stack<List<Query>> queryStack = new Stack<List<Query>>();

    public void visit(SearchCondition<T> sc) {
                
        PrimitiveStatement statement = sc.getStatement();
        if (statement != null) {
                // ex "a > b"
                // use statement.getValue()
                // use statement.getConditionType() such as greaterThan, lessThan
                // use statement.getProperty();
                // to convert "a > b" into Query object
                Query query = buildSimpleQuery(statement);
                queryStack.peek().add(query);                 

        } else {
            // composite expression, ex "a > b;c < d"
            queryStack.push(new ArrayList<Query>());

            for (SearchCondition<T> condition : sc.getSearchConditions()) {
                condition.accept(this);
            }

            boolean orCondition = sc.getConditionType() == ConditionType.OR;
            List<Query> queries = queryStack.pop();
            queryStack.peek().add(createCompositeQuery(queries, orCondition));
        }
    }

    public Query getResultgetQuery() {
        return queryStack.peek().get(0);
    }
}

@Path("/search")
public class SearchEngine {
    @Context
    private UriInfo ui;

    @GET
    public List<Book> findBooks() {
        MultivaluedMap<String, String> params = ui.getQueryParameters();
        String query = params.getFirst("_s"); // or $filter, etc
        // delegate to your own custom handler 

        // note that the original search expression can also be retrieved 
        // using a SearchContext.getSearchExpression() method
}

import java.util.ArrayList;
import java.util.List;
import org.apache.cxf.jaxrs.JAXRSServerFactoryBean;
import org.apache.cxf.jaxrs.ext.search.QueryContextProvider;
import org.apache.cxf.jaxrs.ext.search.SearchBean;
import org.apache.cxf.jaxrs.ext.search.visitor.SBThrealLocalVisitorState;
import org.apache.cxf.jaxrs.ext.search.sql.SQLPrinterVisitor;

import books.BookStore;

// Register the visitor:
JAXRSServerFactoryBean sf = new JAXRSServerFactoryBean();
List<Object> providers = new ArrayList<Object>();
providers.add(new QueryContextProvider());
sf.setProviders(providers);

SQLPrinterVisitor<SearchBean> sqlVisitor = new SQLPrinterVisitor<SearchBean>("books");
sqlVisitor.setVisitorState(new SBThrealLocalVisitorState());
sf.getProperties(true).put("search.visitor", sqlVisitor);


sf.setResourceClasses(BookStore.class);
server = sf.create();

@Path("/")
public class BookStore { 
    @GET
    @Path("/books/{expression}")
    @Produces("application/xml")
    public List<Book> getBookQueryContext(@PathParam("expression") String expression, 
                                      @Context QueryContext searchContext) 
        throws BookNotFoundFault {
        String sqlExpression = searchContext.getConvertedExpression(expression, Book.class);
        // pass it to the SQL DB and return the list of Books
    }
}

// GET /search?a=a1&a=v2
String exp = searchContext.getSearchExpression();
assertEquals("(a==a1,a==a2)", exp);

// GET /search?a=a1&b=b1
exp = searchContext.getSearchExpression();
assertEquals("(a==a1;b==b1)", exp);