Looking for an HQL builder (Hibernate Query Language)

Question

I\'m looking for a builder for HQL in Java. I want to get rid of things like:

StringBuilder builder = new StringBuilder()
    .append(\"select stock from \")
            


        

Answer 1

It looks like you want to use the Criteria query API built into Hibernate. To do your above query it would look like this:

List<Stock> stocks = session.createCriteria(Stock.class)
    .add(Property.forName("id").eq(id))
    .list();

If you don't have access to the Hibernate Session yet, you can used 'DetachedCriteria' like so:

DetachedCriteria criteria = DetachedCriteria.forClass(Stock.class) 
    .add(Property.forName("id").eq(id));

If you wanted to get all Stock that have a Bonus with a specific ID you could do the following:

DetachedCriteria criteria = DetachedCriteria.forClass(Stock.class)
     .createCriteria("Stock")
          .add(Property.forName("id").eq(id)));

For more infromation check out Criteria Queries from the Hibernate docs

Answer 2

Now are also available the standard JPA Type Safe query and an less standard but also good Object Query

Examples:

JPA Type Safe

EntityManager em = ...
CriteriaBuilder qb = em.getCriteriaBuilder();
CriteriaQuery<Stock> c = qb.createQuery(Stock.class);
Root<Stock> = c.from(Stock.class);
Predicate condition = qb.eq(p.get(Stock_.id), id);
c.where(condition);
TypedQuery<Stock> q = em.createQuery(c); 
List<Stock> result = q.getResultList();

Object Query

EntityManager em = ...
ObjectQuery<Stock> query = new GenericObjectQuery<Stock>(Stock.class);
Stock toSearch = query.target();
query.eq(toSearch.getId(),id);
List<Stock> res = (List<Stock>)JPAObjectQuery.execute(query, em);

Answer 3

I wrote a GPL'd solution for OMERO which you could easily build suited to your situation.

• Source: QueryBuilder.java
• Test: QueryBuilderMockTest

Usage:

QueryBuilder qb = new QueryBuilder();
qb.select("img");
qb.from("Image", "img");
qb.join("img.pixels", "pix", true, false);

// Can't join anymore after this
qb.where(); // First
qb.append("(");
qb.and("pt.details.creationTime > :time");
qb.param("time", new Date());
qb.append(")");
qb.and("img.id in (:ids)");
qb.paramList("ids", new HashSet());
qb.order("img.id", true);
qb.order("this.details.creationEvent.time", false);

It functions as a state machine "select->from->join->where->order", etc. and keeps up with optional parameters. There were several queries which the Criteria API could not perform (see HHH-879), so in the end it was simpler to write this small class to wrap StringBuilder. (Note: there is a ticket HHH-2407 describing a Hibernate branch which should unify the two. After that, it would probably make sense to re-visit the Criteria API)

Answer 4

I know this thread is pretty old, but I also was looking for a HqlBuilder And I found this "screensaver" project
It is NOT a Windows screensaver, it's a "Lab Information Management System (LIMS) for high-throughput screening (HTS) facilities that perform small molecule and RNAi screens."

It contains an HQLBuilder that is looking quite good.
Here is a sample list of available methods:

...
HqlBuilder select(String alias);
HqlBuilder select(String alias, String property);
HqlBuilder from(Class<?> entityClass, String alias);
HqlBuilder fromFetch(String joinAlias, String joinRelationship, String alias);
HqlBuilder where(String alias, String property, Operator operator, Object value);
HqlBuilder where(String alias, Operator operator, Object value);
HqlBuilder where(String alias1, Operator operator, String alias2);
HqlBuilder whereIn(String alias, String property, Set<?> values);
HqlBuilder whereIn(String alias, Set<?> values);
HqlBuilder where(Clause clause);
HqlBuilder orderBy(String alias, String property);
HqlBuilder orderBy(String alias, SortDirection sortDirection);
HqlBuilder orderBy(String alias, String property, SortDirection sortDirection);
String toHql();
...

Answer 5

For a type-safe approach to your problem, consider Querydsl.

The example query becomes

HQLQuery query = new HibernateQuery(session);
List<Stock> s = query.from(stock, bonus)
  .where(stock.someValue.eq(bonus.id))
  .list(stock);

Querydsl uses APT for code generation like JPA2 and supports JPA/Hibernate, JDO, SQL and Java collections.

I am the maintainer of Querydsl, so this answer is biased.

Answer 6

Doesn't the Criteria API do it for you? It looks almost exactly like what you're asking for.