ArrayList或Map？ 也帮助如何存放孩子

Question

I'm working on a project that has two classes. One that creates a class that defines a Person and another called FamilyInfo that creates either an ArrayList or Map. FamilyInfo reads in a Scanner that is from a text file of names and their mother father relationships.

The names.txt file first has a list of all the names. Then lists a name, the mother, then the father. Example:

Henry VII
Arthur
Elizabeth of York
etc
etc
...
END OF NAMES, CHILD/MOTHER/FATHER records follow:
-
Arthur
Elizabeth of York
Henry VII
-
Henry VIII
Elizabeth of York
Henry VII
-
etc
etc

This is my Person class so far:

import java.util.*;

public class Person {

    private String name;
    private String mother;
    private String father;
    private ArrayList<String> kids;

    public Person(String name, String mother, String father) {
        this.name = name;
        this.mother = mother;
        this.father = father;
    }

    public Person(String name, String mother, String father, ArrayList<String> kids) {
        this.name = name;
        this.mother = mother;
        this.father = father;
        this.kids = kids;
    }

    public String getName() {
        return name;
    }

    public String getMother() {
        return mother;
    }

    public String getFather() {
        return father;
    }

    public String nthKid(int i) {
        return kids.get(i);
    }

    public int numKids() {
        return kids.size();
    }
}

This is what I have for FamilyInfo:

import java.util.*;

public class FamilyInfo {

    private Map<String, Person> personMap;

    public FamilyInfo() {
        personMap = new HashMap<String, Person>();
    }

    public void read(Scanner input) {
        ArrayList<String> kids = new ArrayList<String>();

        while(input.hasNextLine()) {
            String name = input.nextLine();
            if(name.equals("-")) {
                continue;
            }
            if(personMap.containsKey(name)) {
                String mother = input.nextLine();
                String father = input.nextLine();

                personMap.put(name, new Person(name, mother, father));
            } else {
                personMap.put(name, null);
            }
        }
    }

    public Person getPerson(String names) {
        return personMap.get(names);
    }
}

The issue that I have is figuring out how to store the kids. I have it passing an ArrayList of them but I have no idea how to get them and pass it. Also wondering if using a map is the best way to go about this or should I maybe change it to an ArrayList? Any help is appreciated!

Answer 1

Ok I think I see what you want to do. Consider the following refactoring:

First make your instance variables in the Person class of type Person:

private String name;
private Person mother;
private Person father;
private ArrayList<Person> kids = new ArrayList<Person>();

Then remove the constructors add this one:

public Person(String name) {
    this.name = name;
}

but in addition to this, have setters to set the mother and father, and a way to add kids to the list of kids:

public void setMother(Person mother) {
    this.mother = mother;
}

public void getFather(Person father) {
    this.father = father;
}

public void addKid(Person kid) {
    this.kids.add(kid);
}

---

Now moving on to the FamilyInfo class, using a map is good, because you want to be able to look up the people in the database quickly. The real magic happens in the while loop:

 while(input.hasNextLine()) { String name = input.nextLine(); if(name.equals("-")) { continue; } if(personMap.containsKey(name)) { // find the people Person mother = personMap.get(input.nextLine()); Person father = personMap.get(input.nextLine()); Person kid = personMap.get(name); // link them up kid.setMother(mother); kid.setFather(father); mother.addKid(kid); father.addKid(kid); } else { personMap.put(name, new Person(name)); // create the people objects from the initial list } } 

Answer 2

Are you expected to use these classes, or are they of your own making?

In your model, you have described a person. A person has parents (mother, father), but parents are people too - you should probably model them as such.

So we can say a person has one father and one mother, each parent can have 1 or more children. Parents know their children and children know their parents - this should tell you how to model the relationships. This would make the FamilyInfo redundant as each person would manage it's own relationships.

You should make the process of reading the data and creating the objects external to the model.

@user2864740 comment is still valid and you will need to understand the difference