DATAMONGO-972 - Handle references correctly when using QueryDSL.

[christophstrobl]

!!! DO NOT MERGE !!! - it's a discussion base.

SpringDataMongodbSerializer now uses the overrides for isReference and asReference to create the appropriate DBRef when serializing.

Therefore we look for the meta-annotation @Reference and inspect the given Path to determine the property and its meta information like collection.

ATTENTION

• The change will only take effect when using QueryDSL 3.4.1 and above. See Improve mongodb reference handling querydsl/querydsl#803 for details.
• This change requires to run on java 7. See Upgrade to Querydsl 3.4.2 spring-data-build#90 for details.

Run it anyway
mvn -Dquerydsl=4.3.1 clean install

[odrotbohm]

Applied to master and bugfix branch. Ignored test cases for now. See the ticket for details.

[simonered]

Seems not to work anymore.

Trying to use eq on reference's $id, with no luck.

This is my simplified code:

public class Book {
     @DBRef
     private Library library;
} 

public class Library {
     @Id
     private String id;
}

[...]

String library_id = [SOME_ID];
QBook book = QBook.book;
BooleanExpression exp = book.library.id.eq(library_id);

List<Book> list = bookRepository.findAll(exp);  // EMPTY

Doing:

Library library = libraryRepository.findById(library_id);
QBook book = QBook.book;
BooleanExpression exp = book.library.eq(library);

List<Book> list = bookRepository.findAll(exp);  // EXPECTED ITEMS

or:

List<Book> list = bookRepository.findByLibraryId(library_id)   // EXPECTED ITEMS

[christophstrobl]

@simonered please open an issue in JIRA and provide versions of sd-mongodb and querydsl used. thanks!

[simonered]

Opened