How To Apply Example Matcher in JPA custom findAll query-CodePudding

hi I am trying to make a JPA custom query call using Examplematcher . Below is the code i am trying . If i get the stateId i need to use it in query condition otherwise i need pull all counties irrespective of state . I dont want to make two repo calls like to achieve it in a single repo call .

StateCountyId stateCountyId = new StateCountyId();
StateCounty stateCounty = new StateCounty();
if(null != stateId){
  stateCountyId.setStateId(stateId);
}
stateCounty.setStateCountyId(stateCountyId);
return countiesRepository.findAllByStateCountyIdStateIdOrderByStateCountyIdCountyNameAsc
 (Example.of(stateCounty,  ExampleMatcher.matchingAll().withIgnoreCase()))
 .stream().map(this::countyAsDropDown).collect(Collectors.toList());

@Repository
public interface CountiesRepository extends JpaRepository<StateCounty, StateCountyId> {
List<StateCounty> findAllByStateCountyIdStateIdOrderByStateCountyIdCountyNameAsc(Example 
stateId);
}


@Entity
@Builder
public class StateCounty implements Serializable {
@EmbeddedId
StateCountyId stateCountyId;
@Column(name = "CODE_NBR")
private String codeNbr;
}

@Embeddable
@EqualsAndHashCode
public class StateCountyId implements Serializable {
@Column(name = "STATE_ID")
private String stateId;
@Column(name = "COUNTY_NAME")
private String countyName;
}

If i make the repo call with just string stateId like below its working , but if stateId is empty it will bring back empty result , i need all need to comeback .

countiesRepository.findAllByStateCountyIdStateIdOrderByStateCountyIdCountyNameAsc
(stateId)
.stream().map(this::countyAsDropDown).collect(Collectors.toList());

CodePudding user response：

Use a Specification like this:

@Repository
public interface CountiesRepository extends JpaRepository<StateCounty, StateCountyId> {
  List<StateCounty> findAllByStateCountyIdStateIdOrderByStateCountyIdCountyNameAsc(Specification<StateCounty> specification);
}

countiesRepository.findAllByStateCountyIdStateIdOrderByStateCountyIdCountyNameAsc(
    (root, query, cb) -> {
        if (stateId == null) return null;
        return cb.equal(root.get("stateCountyId").get("stateId"), stateId);
    }
)
.stream().map(this::countyAsDropDown).collect(Collectors.toList());