如何使用 java 从 model 动态计算 null 字段的计数

Question

How to calculate profile completion percentage? Refer to the below Profile model file, Each attribute is another model(EX: BasicInfo has some 15 elements, need to take the count of this and then finally adding the count of this one to Profile total count). I need to get BasicInfo count dynamically without adding if condition check for all fields. Refer the below code

Logic:

1. Each attribute has a weight of 1
2. There are 13 elements in Profile
3. Each attribute has many elements (assuming BasicInfo has 15 and user has filled 10), then you should return 10/15 = 0.67
4. Then sum all of the attributes and divide by 13.

// model sample

Profile.java

    private BasicInfo basicInfo;

    private ReligionInfo religionInfo;

    private LocationInfo locationInfo;

    private ProfessionalInfo professionalInfo;

    private FamilyInfo familyInfo;

    private LifestyleInfo lifestyleInfo;

    private Configuration configuration;

    private BasicPreferences basicPreferences;

    private ReligionPreferences religionPreferences;

    private LocationPreferences locationPreferences;

    private ProfessionalPreferences professionalPreferences;

// What I tried

public long getProfileList(String id) {
   Profile profile = findById(id);
    int count = getBasicInfo(profile);
   
    
    return count;
    }
  
  private int getBasicInfo(Profile profile) {
      
        int counter = 0;
        if (ObjectUtils.isEmpty(profile.getBasicInfo().getBirthDate())) {
            counter++;
        }

        if (ObjectUtils.isEmpty(profile.getBasicInfo().getDobt())) {
            counter++;
        }
        
        return counter;
    }

Answer 1

Have you tried reflection ? You can get all the declared fields of a class. I coded a tiny method to filter nulls as you asked

import java.util.*;
import java.util.stream.*;
import java.lang.reflect.Field;

class Example {
   private String emptyField;
   private String emptyField2;
   private String nonNullField = "non null";
}

public class Main {

    static boolean isFieldNull(Field field, Object obj) {
        try {
            return Objects.isNull(field.get(obj));
        } catch(IllegalAccessException ignored) {
            return false;
        }
    }

    public static void main (String[] args) {
        Example main = new Example();
        Field[] fields = Example.class.getDeclaredFields();

        //For getting access to private fields
        Arrays.stream(fields).forEach(f -> f.setAccessible(true));

        System.out.println(Arrays.stream(fields)
            .filter(f -> isFieldNull(f, main))
            .count());

    }

Here's the output of this code

   java -classpath .:/run_dir/junit-4.12.jar:target/dependency/* Main
   2