Question

I have 3 entities Agent, Person and Machine

abstract Agent
  Long id

Person extends Agent
  String firstName
  String lastName

Machine extends Agent
   String label

I searched for a solution to query all my agents on given parameter "name", which would lookup on firstName and lastName of Person, or on label of Machine.

Is it possible with a jpql query?

Thanks

Answer 1

I am a little late but since querydsl 3.6.2(which corrected the use of instanceOf), you can do this with java code.

BooleanBuilder builder = new BooleanBuilder();
QAgent qAgent = QAgent.Agent;
builder.or(qAgent.as(QPerson.class).firstName.eq("someFirstName")
.and(qAgent.instanceOf(Person.class));

builder.or(qAgent.as(QMachine.class).label.eq("someLabel")
.and(qAgent.instanceOf(Machine.class));

Page<Agent> agentsPage = agentRepository.findAll(builder);

On the downside i would reconsider your class structure, this will result in union queries, if you could use a projection with common properties on the superclass maybe the resulting query would be less expensive.

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