[FIXED] Spring data mongoDB : Find all by child object id with Example Executor and Pageable

Issue

I am facing issue in querying repository with find all by child object ID, Example and Pageable.

StudentController.java

@RestController
@RequestMapping("/students")
public class StudentController {
    @Autowired
    private StudentService studentService;
    
    @RequestMapping(method = RequestMethod.GET)
    public Page<Student> getStudentsPage(
            @PageableDefault(page = 0, size = 10) @SortDefault.SortDefaults({
                    @SortDefault(sort = "id", direction = Direction.DESC) }) Pageable pageable,
            Student student) {
        return studentService.getStudentPage(student, pageable);
    } 
}

StudentService.java

@Service
public class StudentService {
    private static final Logger logger = LoggerFactory.getLogger(StudentService.class);    
    @Autowired
    private UserService userService;
    
    @Autowired
    private StudentRepository studentRepository;
    
    public Page<Student> getStudentsPage(Student student, Pageable pageable) {
        logger.debug("Getting Students : {}, {}", student, pageable);
        //gets organization Id of the student from the session
        String organizationId = userService.getUserMe().getOrganization().getId(); 
        Page<Student> studentPage = studentRepository.findAllByOrganizationId(organizationId, Example.of(student), pageable);
        
        logger.debug("Students: {}", studentPage.getContent());
        return studentPage;
    }
}

StudentRepository.java

@Repository
public interface StudentRepository extends MongoRepository<Student, String> {    
    Page<Student> findAllByOrganizationId(String organizationId, Example<Student> example, Pageable pageable);
    
}

Student.java

@Document(collection = "students")
public class Student {
    @Id
    private String       id;
    private String       firstName;
    private String       lastName;
    @DBRef(db = "organizations")
    private Organization organization;
    
    public String getId() {
        return id;
    }
    
    public void setId(String id) {
        this.id = id;
    }
    
    public String getFirstName() {
        return firstName;
    }
    
    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }
    
    public String getLastName() {
        return lastName;
    }
    
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    
    public Organization getOrganization() {
        return organization;
    }
    
    public void setOrganization(Organization organization) {
        this.organization = organization;
    }
    
    @Override
    public String toString() {
        return "Student [id=" + id + ", firstName=" + firstName + ", lastName=" + lastName + ", organization="
               + organization + "]";
    }
    
}

Organization.java

@Document(collection = "organizations")
public class Organization {
    @Id
    private String id;
    private String name;
    
    public String getId() {
        return id;
    }
    
    public void setId(String id) {
        this.id = id;
    }
    
    public String getName() {
        return name;
    }
    
    public void setName(String name) {
        this.name = name;
    }
    
    @Override
    public String toString() {
        return "Organization [id=" + id + ", name=" + name + "]";
    }
    
}

The GET API request: http://localhost:8080/students?page=0&size=10&sort=id,desc&lastName=xyz

the repository method Page findAllByOrganizationId(String organizationId, Example example, Pageable pageable); should return all the records with matching organizationId and lastName=xyz, But it returns the records that match with the organization Id along with all the students irrespective of the lastName.

Is something wrong with the code?

Solution

Finally found answer. findBy and Example Executor doesn't work together.

By setting the child object filter and query by Example Executor as shown below.

public Page<Student> getStudentsPage(Student student, Pageable pageable) {
        logger.debug("Getting Students : {}, {}", student, pageable);
        //gets organization Id of the student from the session
        String organizationId = userService.getUserMe().getOrganization().getId(); 
        student.setOrganization(new Organization(organizationId));
        Page<Student> studentPage = studentRepository.findAll(Example.of(student), pageable);
        
        logger.debug("Students: {}", studentPage.getContent());
        return studentPage;
    }    

This works as expected!!

Thanks!!

Answered By - Mallikarjun Vishwanath