Spring Boot: Get an object from MongoDB document? - mongodb

Question

I am using Spring Boot 2.1.3.RELEASE and MongoDB. And I am looking for a way to retrieve a part of a document.
Repository:
#Repository
public interface CompanyRepository extends MongoRepository<Company, String> {
}
Object:
#Data
#Document
public class Company {
public GeneralInfo info;
public Map<String, List<Employee>> officeIdEmployeeMap;
#Data
public class GeneralInfo {
#Id
public String companyId;
public String name;
}
#Data
public class Employee {
public String firstName;
public String lastName;
}
}
I need to get only GeneralInfo objects and then if some conditions are true get the List<Employee> from the officeIdEmployeeMap, not the whole map.
Can this be done by MongoRepository?

Answer 1

This is possible with MongoTemplate.
finalString officeName = "IT";
final Query query = new Query();
query.addCriteria(Criteria.where("officeIdEmployeeMap." + officeName).exists(true));
query.fields().exclude("officeIdEmployeeMap");
final Company company = mongoTemplate.findOne(query, Company.class, "collection");
This will return the Company object but only GeneralInfo will be set.

Answer 2

In CompanyRepository add the following method:
#Query(value="{}", fields = "{'info':1}")
public List<Company> getCompanies();
Call this when you need to get only General Info otherwise, call findAll() to get all details. You may write a new Query in the repository restricting the selected fields and optionally the criteria.
In case you want to achieve both the scenarios (get GeneralInfo only and get both) in the same query conditionally, instead of annotation create a query like below:
#Autowired
private MongoTemplate mongoTemplate;
Query query = new Query();
boolean someCondition = true; // Put your condition here
if(someCondition) {
query.fields().exclude("officeIdEmployeeMap");
}
return mongoTemplate.find(query, Company.class);
Assuming your company data in the database looks like this:
{ "_id" : ObjectId("5d3afb75b2ebf8a9ec2f906f"), "info" : { "companyId" : "1", "name" : "abc" }, "officeIdEmployeeMap" : { "g1" : [ { "firstName" : "A", "lastName" : "B" }, { "firstName" : "C", "lastName" : "D" } ] } }