Recursive Methods

[Henrique Ordine]

hello everyone,
I wrote this dummy tree class which is associated to itself, and i populate it using a recursive method. The recursive method, getMyChildren, is used to add child objects to parent object, and then grandchildren to children, and so on.
In my method, after the recursion, I test the collection of children and they're always empty, even though they're not.
Does anyone know why this happens? I would appreciate any thoughts.

Here is my code:

public class RecursiveClass {

private String name;
private int level;
private RecursiveClass parent;
private Collection<RecursiveClass> children = new ArrayList<RecursiveClass>(); 

public static void main(String[] args) {
RecursiveClass parent = new RecursiveClass();
parent.getMyChildren();
}

public void getMyChildren() {
for (int i = 0; i < 5; i++) {
RecursiveClass element = new RecursiveClass();
element.name = "Name " + i;
element.setLevel(this.getLevel() + 1);
element.setParent(this);
if (element.getLevel() < 3)
element.getMyChildren();
// here element.getChildren() is always an empty collection
if (!element.getChildren().isEmpty())
this.getChildren().add(element);
}
}
 
public String getName() {
return name;
}
 
public void setName(String name) {
this.name = name;
}
 

public boolean equals(Object obj) {
if (!(obj instanceof RecursiveClass))
return false;
if (obj == null)
return false;
return ((RecursiveClass)obj).getName().equals(name);
}
 
public int getLevel() {
return level;
}
 
public void setLevel(int level) {
this.level = level;
}
 
public RecursiveClass getParent() {
return parent;
}
 
public void setParent(RecursiveClass parent) {
this.parent = parent;
}
 
public Collection<RecursiveClass> getChildren() {
return children;
}
 
public void setChildren(Collection<RecursiveClass> children) {
this.children = children;
}
}

[Ernest Friedman-Hill]

I'm having an extremely hard time following the logic here, or why a method called "getMyChildren" would be the way to build a a tree in the first place. But in any case, there's only one place in the whole program where you call children.add():

if (!element.getChildren().isEmpty())
    this.getChildren().add(element);

So if there are already some children, add a new child. But of course, since we start out with no children, that's never going to change.