用于ManyToMany的QueryDSL代码生成

Question

I'm porting some complex JPQL queries in a large Hibernate/JPA2 application to use QueryDSL 2.3.0, and I'm stuck on one.

My Client entity contains

@ManyToMany
private List<Group> groups;

My existing query fragment is

EXISTS(SELECT g FROM Group g WHERE g MEMBER OF slr.groups AND 
             UPPER(g.description) LIKE :group)

The QueryDSL code generation has produced the following in my QClient class:

public final SimplePath<java.util.List<Group>> groups = 
          createSimple("groups", java.util.List.class);

The code generation using SimplePath doesn't let me use the in or contains methods to query membership. I think I need a CollectionPath instead. Is there a way to annotate the Client class so that QueryDSL uses the correct type for querying a collection?

Answer 1

I have an answer. This looks like a bug introduced in QueryDSL 2.2.5, which only happens when working in Eclipse .

The correct solution is to not use Eclipse to generate the source (don't enable annotation processing). Instead, I'm using m2eclipse and generating the source in Maven.

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For reference, my first workaround was to extend the generated QClient class with my own QQClient class, which adds one member:

public final ListPath<Group, QGroup> fixedgroups = 
                  createList("groups", Group.class, QGroup.class);

At that point the equivalent to my original query is:

QGroup g = QGroup.group;
JPQLSubQuery subquery = new JPQLSubQuery().from(g);
subquery = subquery.where(slr.fixedgroups.contains(g), 
    g.description.upper().like("%" + group.toUpperCase() + "%"));
query = query.where(subquery.exists());

( query is the larger query this is part of. slr is an instance of QQClient brought into the outer query by a left join.)