How to programatically trigger javax validations in a POJO class

Question

I have a spring boot project in which I'm facing a data validation issue while doing a post request.

Problem

While doing a post request I'm mapping the request body to a POJO which does not have any javax validations in itself, but the class has fields of another two POJOs which have data validations in them. How can I trigger data validations in the inner POJOs programmatically and throw relevant exceptions if required. I'm using Spring boot v2.5.2.

In the post request I have:

@PostMapping("/signup")
public ResponseEntity<String> addNewUser(@RequestBody @Valid NewUserDetailsPojo newUserDetailsPojo) {
    log.debug("Adding new User: {}", newUserDetailsPojo);
    Integer userId = userService.addNewUser(newUserDetailsPojo);
    if (userId == null) {
        return ResponseEntity.badRequest().build();
    } else {
        URI location = ServletUriComponentsBuilder.fromCurrentRequest().path("/{id}").buildAndExpand(userId).toUri();
        return ResponseEntity.created(location).build();
    }
}

Where NewUserDetailsPojo is a simple POJO class having structure:

public class NewUserDetailsPojo {  
private BasicDetailsPojo basicDetailsPojo;   
private DoctorPojo doctorPojo;

// constructor
public NewUserDetailsPojo(BasicDetailsPojo basicDetailsPojo, DoctorPojo doctorPojo) {
    /** before mapping the incoming data to the fields, I want to validate the data
    * with my predefined javax.validations constraints declared in the respective 
    * classes
    */
    this.basicDetailsPojo = basicDetailsPojo;
    this.doctorPojo = doctorPojo;
  }
}

So, as I mentioned earlier, NewUserDetailsPojo does not have any data validations in itself, but its two fields which are of the class

• BasicDetailsPojo
• DoctorPojo

have data validations in them. I want to invoke javax validations in the constructor of NewUserDetailsPojo and throw suitable exceptions if nessecery.

I'm giving the structures of BasicDetailsPojo and DoctorPojo below:

public class BasicDetailsPojo {
  @Size(min = 5, message = "Name should be at least 5 characters long")
  private String name;
  @Email
  private String email;
  @Size(min = 10, message = "Contact number must be of 10 digits")
  private String contactNo;
  private String role;
  @NotNull
  @Size(min = 8, message = "Password must be 8 characters long")
  private String password;
}

This is the structure of DoctorPojo:

public class DoctorPojo extends BasicDetailsPojo {
  @NotNull
  private String regNo;
  @NotNull
  private String degree;
  @NotNull
  private String specialization;
  private String experience;
}

Answer 1

I think your problem will be fixed by putting @Valid annotation in the NewUserDetailsPojo class over the basicDetailsPojo and doctorPojo atributes https://docs.jboss.org/hibernate/stable/validator/reference/en-US/html_single/?v=5.3#section-object-graph-validation