Adding and object to list inside while loop
I am trying to loop through a list and this list contains 4 arrays inside and each array has 7 values
I loop through the list and then when I get the array from the list, since I know how many values the array has, I assign each array index like this: personObject.setName(String.valueOf(myArray[0])
and then at the end of the while loop I add to the list of persons, for personObject: listOfPersons. add (personObject).
My problem is that my list is only filled with the same object, and I know that the 4 arrays inside the list that I loop have different values, here is my code:
ArrayList<Object> objectList= null;
objectList= _serviceVariable.getObjects(); <--- this works it returns a list with 4 arrays all with diferent values
Person myPerson = new Person();
List<Person> personsList = new List<Person>;
Iterator<Object> itr = objectList.iterator();
while(itr.hasNext())
{
Object[] innerObj = (Object[]) itr.next();
myPerson.setName(String.valueOf(innerObj [0])
myPerson.setLastName(String.valueOf(innerObj [1])
myPerson.setNickName(String.valueOf(innerObj [2])
personsList.add(myPerson);
}
when i print the list of my faces, populated with people with the same name, lastName and nickname, is a list full of the same objects with the same values.
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Every time you add Person
, do you want to add another person?
Therefore, you must create an object inside the loop every time . Don't create just one outside of the loop whose data you just change. new
Person
// NOT HERE Person myPerson = new Person();
// ...
while(itr.hasNext()) {
Object[] innerObj = (Object[]) itr.next();
Person myPerson = new Person(); // HERE you create a new Person
myPerson.setName(String.valueOf(myArray[0]);
myPerson.setLastName(String.valueOf(myArray[1]);
myPerson.setNickName(String.valueOf(myArray[2]);
personsList.add(myPerson); // add the new person to the list
}
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You are adding (and modifying) the same object instance to the loop multiple times, because you only create one instance Person
, move it into the loop.
// Person myPerson = new Person();
// ...
while(itr.hasNext()) {
Person myPerson = new Person(); // <-- HERE!
Object[] innerObj = (Object[]) itr.next();
myPerson.setName(String.valueOf(myArray[0])
myPerson.setLastName(String.valueOf(myArray[1])
myPerson.setNickName(String.valueOf(myArray[2])
personsList.add(myPerson);
}
And you will create multiple instances and add them to your loop.
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After looking at the code it seems to me.
You are not reading data from a sibling array that innerObj
. replace myArray[0]
, it must be innerObj [0] and
Person p = new Person()
inside the loop to set the new value, otherwise it will be canceled.
while(itr.hasNext()) {
Person p= new Person(); // <-- HERE!
Object[] innerObj = (Object[]) itr.next();
p.setName(String.valueOf(innerObj [0])
p.setLastName(String.valueOf(innerObj [1])
p.setNickName(String.valueOf(innerObj [2])
personsList.add(p);
}
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public class Foobar {
class Person {
String name;
Person(String name) {
this.name = name;
}
}
class SpecialPerson extends Person {
SpecialPerson(String name) {
super(name);
}
}
public void myFoobar() {
List<List<Person>> ListOfPersonsList = new ArrayList<List<Person>>();
List<Person> persons1 = new ArrayList<Person>();
persons1.add(new Person("Foo"));
List<Person> persons2 = new ArrayList<Person>();
persons2.add(new Person("Bar"));
ListOfPersonsList.add(persons1);
ListOfPersonsList.add(persons2);
List<SpecialPerson> specials = new ArrayList<SpecialPerson>();
for (List<Person> persons : objectList) {
for (Person person : persons) {
specials.add(new SpecialPerson(person.name));
}
}
for (SpecialPerson special : specials) {
System.out.println("Name: " + special.name);
}
}
}
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