Java中的RavenDB查询别名

Question

I'm sure I'm missing the glaringly obvious, but I can't figure out what the "Q"-prefixed types are supposed to be, or how to resolve them. Basically, all over the Java documentation, QSomething classes are used, yet I can't find an explanation what they really are, how the prefix works, or how they are resolved. Even at the very beginning, here , QCategory c = QCategory.category; is used without any pointers as to how those Q-prefixed types are resolved. Predictably, when I try to create an object according to that syntax logic, I get "[abc] cannot be resolved to a type". So if someone could shed some light on that "mystical" Qsometype stuff, I'd be very grateful.

Edit: I'm not currently using Maven for my Eclipse setup (the tutorial mentions Maven pom) Is this impossible without using Maven ? I've investigated some more and I understand the Q-classes are auto-generated by QueryDSL and Maven. My project type in Eclipse is dynamic web, and I'm not sure I want to/should convert this to a Maven project. In fact, I'm not even sure that would solve my problem.

Thanks

Answer 1

Those are auto generated classes, if you setup using Maven, it just works. The configuration entry for this is <processor>net.ravendb.querydsl.RavenDBAnnotationProcessor</processor>

This is using QueryDSL to generate the query classes.

The explanation in the docs is:

Please note that plugins section contains net.ravendb.querydsl.RavenDBAnnotationProcessor . As Java does not have LINQ, all definitions of indexes/transformers must be created using strings. Alternatively, you can use the Studio to create indexes/transformers, yet you can also use QueryDSL for strongly-typed querying. In order to use QueryDSL you have to mark your entities with @QueryEntity annotation and enable code generation in pom.xml.

You can generate this manually, see http://www.querydsl.com/static/querydsl/2.7.3/reference/html/ch03s02.html