I have an repository layer that have many methods combination, to match search criterias.. What is the best approach to reuse this criterias? I think that methods name like findByNameAndIdAndBirthdayAndAccounaNumber is not a good idea ! Thanks !
public Order findByIdAndName(String orderId) {
List<OrderEntity> list = entityManager.createNamedQuery(OrderEntity.QUERY_FIND_BY_ORDERID_AND_NAME, OrderEntity.class)
.setParameter("orderId", orderId)
.setParameter("name", name).getResultList();
if (list.isEmpty()) {
return null;
}
OrderEntity orderEntity = list.get(0);
return toOrder(orderEntity);
}
Sounds like you may be looking for the Specification pattern which would allow you write a method like:
public Order findOrderBySpecification(Specification specification) {
}
and then call this using a combination of one or more specifications eg by account number, by account number and name etc.
There is an example here using the Criteria API:
http://java.dzone.com/articles/java-using-specification
See also the article below which refers to the Spring Data project but which is probably worth a read anyway even if you are not using Spring.
http://spring.io/blog/2011/04/26/advanced-spring-data-jpa-specifications-and-querydsl/
Also, you can achieve this more simply using the QueryDSL library referenced in the article above rather than the rather verbose Criteria API with Straight JPA (ie without Spring).
http://blog.mysema.com/2010/04/querydsl-as-alternative-to-jpa-2.html http://www.querydsl.com/static/querydsl/2.1.0/reference/html/ch02s02.html
Try to use the specification pattern in your repository implementation.
OrderSpecificationByName.java
public class OrderSpecificationByName implements OrderSpecification, HibernateSpecification {
private String name;
public OrderSpecificationByName(String name) {
super();
this.name = name;
}
@Override
public boolean isSatisfiedBy(Object order) {
return ((Order)order).hasName(name);
}
@Override
public Criterion toCriteria() {
return Restrictions.eq("name", name);
}
}
OrderSpecificationById.java
public class OrderSpecificationById implements OrderSpecification, HibernateSpecification {
private Long id;
public OrderSpecificationById(String id) {
super();
this.id = id;
}
@Override
public boolean isSatisfiedBy(Object order) {
return ((Order)order).hasId(id);
}
@Override
public Criterion toCriteria() {
return Restrictions.eq("id", id);
}
}
Then you must implment the logical specifications AndSpecification
, OrSpecification
, NotSpecification
, etc..
AndSpecification.java
public class AndSpecification implements HibernateSpecification {
private Specification first;
private Specification second;
public AndSpecification(Specification first, Specification second) {
first = first;
second = second;
}
@Override
public boolean isSatisfiedBy(Object candidate) {
return first.isSatisfiedBy(candidate) && second.isSatisfiedBy(candidate);
}
@Override
public Criterion toCriteria() {
Conjunction conjuntion = Restrictions.conjunction();
conjuntion.add(first.toCriteria());
conjuntion.add(second.toCriteria());
return conjuntion;
}
}
OrderRepository.java
public List<Order> query(HibernateSpecification specification) {
Session session = sessionFactory.getCurrentSession();
Criteria criteria = session.createCriteria(Order.class);
criteria(specification.toCriteria());
return criteria.list();
}
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