spring-data-mongodb

I have an aggregation pipeline which includes a project like this: $project: { start: { $cond: { if: { $eq: ["$start", "EARLY"] }, then: "$deltastart.start", else: "$deltastart.end" } },... },... which works fine in mongo shell. How to express this using the Aggregation framework in Spring-Mongodb? I have seen ProjectionOperationBuilder, ExpressionProjectionOperationBuilder types but not an example how to use them... any suggestions? If using the current Spring Data release which has support for the $cond operator via the $project pipeline, then this can be converted to (untested): import

I have a very simple Spring Boot application that uses Spring-Data-Mongodb All I want to do is set a JSR-303 validation rule that says the object I'm saving must have a username. I read that JSR-303 was added to spring-data-mongodb in version 1.1 so I assumed that when I save an object it's validated but this isn't the case. Does anyone have a simple example setup that shows how this works? My User pojo looks like public class User { @Id private String id; @NotNull(message = "User Name is compulsory") private String userName; private String password; public User() {} public String getId() {

Mongodb is a no-schema document database, but in spring data, it's necessary to define entity class and repository class, like following: Entity class: @Document(collection = "users") public class User implements UserDetails { @Id private String userId; @NotNull @Indexed(unique = true) private String username; @NotNull private String password; @NotNull private String name; @NotNull private String email; } Repository class: public interface UserRepository extends MongoRepository<User, String> { User findByUsername(String username); } Is there anyway to use map not class in spring data mongodb

I have a trouble(/(ㄒoㄒ)/~~). Suppose that collection A is { "_id" : ObjectId("582abcd85d2dfa67f44127e1"), "bid" : [ DBRef("B", ObjectId("582abcd85d2dfa67f44127e0")), DBRef("B", ObjectId("582abcd85d2dfa67f44127e1")) ] } and Collection B: { "_id" : ObjectId("582abcd85d2dfa67f44127e0"), "status" : NumberInt(1), "seq" : NumberInt(0) }, { "_id" : ObjectId("582abcd85d2dfa67f44127e1"), "status" : NumberInt(1), "seq" : NumberInt(0) } I don't know how to $lookup the 'bid'. I tried db.A.aggregate( [ {$unwind: {path: "$bid"}}, {$lookup: {from: "B", localField: "bid", foreignField: "_id", as: "bs"}}, ] )