LOGICAL TREES in JAVA

Question

hi everyone.
i'm doing a project that requires me to use a tree structure. there is of course jtree but i dont need the user interface, i just need the structure.
may i ask a few minutes from your time to enlighten me regarding this problem.
please tell me the structure to use, and an example how to use it.
please help.(deadline's in a few days.)
thank you.

Answer 1

Here's a simple Node class - to use them as a tree, all you need is a reference any node, usually the root node.
If you run this example you get output like:
+ Root
   + Parent 0
      + Child 0.0
         - GrandChild 0.0.0
         - GrandChild 0.0.1
      + Child 0.1
         - GrandChild 0.1.0
         - GrandChild 0.1.1
   + Parent 1
      + Child 1.0
         - GrandChild 1.0.0
         - GrandChild 1.0.1
      + Child 1.1
         - GrandChild 1.1.0
         - GrandChild 1.1.1
import java.util.Vector;
public class Node
     private Vector mChildren= new Vector();
     private Node mParent;
     private Object mUserData;
     public Node(Object userData) {
          this(userData, null);
     public Node(Object userData, Node parent)
          mUserData= userData;
          mParent= parent;
          if (parent != null)
               parent.addChild(this);
     public Node getParent() {
          return mParent;
     public void addChild(Node child) {
          mChildren.addElement(child);
     public int getChildCount() {
          return mChildren.size();
     public Node getChildAt(int index)
          if (index > getChildCount())
               return null;
          return (Node) mChildren.elementAt(index);
     public boolean isLeaf() {
          return getChildCount() < 1;
     public String toString() {
          return mUserData != null ? mUserData.toString() : "null";
     public static void main(String[] argv)
          Node root= new Node("Root");
          for (int i= 0; i< 2; i++) {
               Node parent= new Node("Parent " +i, root);
               for (int j= 0; j< 2; j++) {
                    Node child= new Node("Child " +i +"." +j, parent);
                    for (int k= 0; k< 2; k++) {
                         Node grandChild= new Node("GrandChild " +i +"." +j +"." +k, child);
          print(root, "");
     private static void print(Node node, String indent)
          System.err.print(indent);
          System.err.print(node.isLeaf() ? "- " : "+ ");
          System.err.println(node);
          for (int i= 0; i< node.getChildCount(); i++)
               print(node.getChildAt(i), indent +"   ");