Using random enum to generate objects in java

Question

There are four classes that interact with my project. The aim is to generate an object using enum, using the random values from enum.

1. The EthicalEngine class. I'll call the method from another class called ScenarioGenerator .
2. The Person class inherited from the Character abstract class.

I am not sure whether my method of initialization is correct or not. My idea is to initialize the instance of the Person in the ScenarioGenerator class, and use a method getRandomPerson() to call the constructor.

But I stuck, keep getting NullPointerException when I called the method.

Here is part of my Character class:

abstract class Character {

private int age;
private Gender gender;
private BodyType bodyType;
protected Profession profession;
protected AgeCategory ageCategory;
protected boolean isPregnant;

public enum Gender {
    MALE, FEMALE, UNKNOWN;
}

public enum BodyType {
    AVERAGE, ATHLETIC, OVERWEIGHT, UNSPECIFIED;
}

public enum Profession {
    DOCTOR, CEO, CRIMINAL, HOMELESS, UNEMPLOYED, MUSICIAN, BOXER ,UNKNOWN, NONE;
}

public Character(int age, Profession profession, Gender gender, BodyType bodyType, boolean isPregnant) {
    this.age = age;
    this.profession = profession;
    this.gender = gender;
    this.bodyType = bodyType;
    this.isPregnant = isPregnant;
}

part of my Person class:

Person(int age, Profession profession ,Gender gender, BodyType bodyType, boolean isPregnant) {
    super(age, profession, gender, bodyType, isPregnant);
}
public Profession getProfession () { //use getter to generate a random value
    //only adults have profession
    if (getAge()<=16 || getAge()>68) {
        return Profession.NONE;
    } else {
        return Profession.values()[new Random().nextInt(Profession.values().length)];
    }
//other getters and setters
}

Part of my ScenarioGenerator class:

public class ScenarioGenerator {

private Person person;
private Animal animal;
private Scenario scenario;
private Random random = new Random();

private int passengerCountMinimum;
private int passengerCountMaximum;

private int pedestrianCountMininum;
private int pedestrianCountMaximum;

public ScenarioGenerator() {
    random.setSeed(random.nextInt());
}

public ScenarioGenerator(long seed) {
    this.random = new Random(seed);  
}

public Person getRandomPerson() {
    //need age, gender, bodyType, profession, pregnancy
    Person people = new Person(person.getAge(), person.getProfession(), person.getGender(),person.getBodyType(), person.isPregnant());      
    return people;
}

Part of my EthicalEngine class:

public class EthicalEngine {
    public static void main(String[] args) throws Exception {
    EthicalEngine ethicalEngine = new EthicalEngine();
    ScenarioGenerator scenarioGenerator = new ScenarioGenerator();
    scenarioGenerator.getRandomPerson();
}

Answer 1

you can generate random number and select all values

import java.util.Random;

public class ScenarioGenerator {

public Person getRandomPerson() {
    Random rand = new Random();

    // max age
    int age = rand.nextInt(100);

    // no of profession - 1
    int profession = rand.nextInt(8);

    // no of gender - 1
    int gender = rand.nextInt(2);

    // no of bodyType - 1
    int bodyType = rand.nextInt(3);

    int pragnency = rand.nextInt(2);

    //need age, gender, bodyType, profession, pregnancy
    Person people = new Person(age, Profession.values()[profession], Gender.values()[gender],BodyType.values()[bodyType], pragnency == 1 ? true : false);
    return people;
}

}