java : Parsing An ArrayList and setting them into a Object

Question

I have these two classes:

class Student
{
String name;
String age ;
}

class Person
{

String name;
String age ;
String grade ;
}

In the code below, I am creating Student objects and setting them inside the ArrayList. Once the data is set in the ArrayList, I need to parse that ArrayList and set the values in another object:

public class Work {

    public static void main(String args[]) {

        List StudentItems = new ArrayList();

        Student stud1 = new Student();
        Student stud2 = new Student();

        stud1.name = "ABC";
        stud1.age = "28";
        stud2.name = "XYZ";
        stud2.age = "38";

        StudentItems.add(stud1);
        StudentItems.add(stud2);

        Person[] pers = new Person[StudentItems.size()];

        for (int i = 0; i < StudentItems.size(); i++) {
            pers[i] = new Person();

// I am confused here , could anyone please help 

        }

    }
}

What is Person class here and what do you want to do with it?? — Sunil Kumar B M
– Sunil Kumar B M, Commented Mar 5, 2012 at 5:58
Why has Person a grade, and Student not? Didn't you mix that up? Why doesn't Student extend Person? — user unknown
– user unknown, Commented Mar 6, 2012 at 1:49

1218985 · Accepted Answer · 2012-03-05 06:31:12Z

Try it out. This will do the work

Your Person class should be something like this:

package com.student.person.work;

/**
 *
 * @author sarath_sivan
 */
public class Person {

    private String name;
    private int age;
    private String grade;

    public String getName() {
       return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return this.age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getGrade() {
        return this.grade;
    }

    public void setGrade(String grade) {
        this.grade = grade;
    }

}

Your Student class should be something like this:

package com.student.person.work;

/**
 *
 * @author sarath_sivan
 */
public class Student {

    private String name;
    private int age;

    public String getName() {
       return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return this.age;
    }

    public void setAge(int age) {
        this.age = age;
    }

}

And finally, the Work class:

package com.student.person.work;

import java.util.ArrayList;
import java.util.List;

/**
 *
 * @author sarath_sivan
 */
public class Work {

    public static String calculateGrade() {
        String grade = "";
        // Your code to find the grade.
        //............
        return grade;
    }

    public static void doWork() {
        List<Student> studentList = new ArrayList<Student>();

        Student student = new Student();
        student.setName("ABC");
        student.setAge(24);
        studentList.add(student);

        student = new Student();
        student.setName("DEF");
        student.setAge(28);
        studentList.add(student);

        student = new Student();
        student.setName("GHI");
        student.setAge(21);
        studentList.add(student);

        List<Person> personList = new ArrayList<Person>();

        for(Student students : studentList) {
            Person person = new Person();
            person.setName(students.getName());
            person.setAge(students.getAge());
            person.setGrade(Work.calculateGrade());// Setting the grade
        }
    }

    public static void main(String[] args) {
        Work.doWork();
    }

}

Hope this will be helpful.

Thank you!

dantuch · Accepted Answer · 2012-03-05 06:14:07Z

Something like this:

    List<Student> studentItems = new ArrayList<Student>();
    Student stud1 = new Student();
    Student stud2 = new Student();

    stud1.name = "ABC";
    stud1.age = "28";
    stud2.name = "XYZ";
    stud2.age = "38";

    studentItems.add(stud1);
    studentItems.add(stud2);

    for (int i = 0; i < studentItems.size(); i++) {
        Student student = studentItems.get(i);
        Person person = new Person();
        person.name = student.name;
        person.age = student.age;
        // person.grade = something - set grade here
        pers[i] = person;
    }

But be avare that you shouldn't use public fields... so it should look like this:

for (int i = 0; i < studentItems.size(); i++) {
    Student student = studentItems.get(i);
    Person person = new Person();
    person.setName(student.getName());
    person.setAge(student.getAge());
    // person.setGrade(computeGradeSomehow()); - set grade here
    persons[i] = person;
}

lucentmind · Accepted Answer · 2012-03-05 06:06:57Z

If you are frequently converting from student object to Person object, add following like constructor and setter/getter method

class Person {

        String name;

        String age;

        String grade;

        public Person() {

        }

        Person(Student student) {
            this.name = student.getName();
            this.age = student.getAge();
        }

        public String getGrade() {
            return grade;
        }

        public void setGrade(String grade) {
            this.grade = grade;
        }
    }

    class Student {
        private String name;

        private String age;

        public void setName(String name) {
            this.name = name;
        }

        public String getName() {
            return name;
        }

        public String getAge() {
            return age;
        }

        public void setAge(String age) {
            this.age = age;
        }
    }

And in Work class, create Person object like,

List<Student> studentItems = new ArrayList<Student>();
 List<Person> personItems = new ArrayList<Person>();

for (int i = 0; i < studentItems.size(); i++) {
        Student student = studentItems.get(i);
        Person person = new Person(student);
        person.setGrade(your_formula_for grade);  
        personItems.add(person); 
}

plucury · Accepted Answer · 2012-03-05 06:02:24Z

0

You can do it as follow：

pers[i].name = StudentItems.get(i).name;

answered Mar 5, 2012 at 6:02

plucury

1,1201 gold badge8 silver badges16 bronze badges

Comments

Silviu Burcea · Accepted Answer · 2012-03-05 06:16:23Z

0

Grade should be in the Student class. If you to this, your classes should look like this:

class Person {
private String name; 
private int age; 

//getters and setters
}

class Student extends Person { // here you have name and age from Person
private String grade;

//getters and setters
}

Now, you want the list of persons from the list of students? You can do this:

for (int i = 0; i < listOfStudents.size(); i++){
arrayOfPersons[i] = (Person)listOfStudents.get(i);
}

answered Mar 5, 2012 at 6:16

Silviu Burcea

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Comments

user unknown · Accepted Answer · 2012-03-06 01:56:18Z

0

Given, that your classes are really properly layouted (see my comment), you could write a constructor for person which takes an Student as input:

        pers[i] = new Person (StudentItems[i]);

note, that I would rename the variables:

        persons [i] = new Person (students[i]);

Your Person with the new CTor would look like this:

class Person
{
  String name;
  String age ;
  String grade ;

  public Person () {}
  public Person (s Student) {
    name = s.name;
    age = s.age;
  }
}

More probably, you want to change the name of Student and Person, and derive Student from Person. Then, every Student is a person, and in your loop, it is justs:

        persons [i] = students[i];

answered Mar 6, 2012 at 1:56

user unknown

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