Filteredtreemodel, how to hide parent nodes if no children

Question

hi. i have surfed and read a lot of posts and topics here regarding filteredtreemodel. some i found hard to understand so i chose to use NiceGuy1's code from long ago since it's the easiest to understand.
package test;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeNode;
import java.util.ArrayList;
import java.util.Enumeration;
public class FilteredTreeModel extends DefaultTreeModel {
    // this hashmap gets the list of pdf files and the filter status
    private String filterText;
    private DefaultMutableTreeNode orig_root;
    public FilteredTreeModel(DefaultMutableTreeNode root) {
        super(root);
        orig_root = root;
    public void setFilterText(String s) {
        this.filterText = s;
        reload();
    public String getFilterText() {
        return this.filterText;
    @Override
    public Object getChild(Object parent, int index) {
        return getFilteredChildren(parent).get(index);
    @Override
    public int getChildCount(Object parent) {
        return getFilteredChildCount(parent);
    @Override
    public int getIndexOfChild(Object parent, Object child) {
        return getFilteredChildren(parent).indexOf(child);
    private int getFilteredChildCount(Object parent) {
        return getFilteredChildren(parent).size();
    private ArrayList<TreeNode> getFilteredChildren(Object parent) {
        ArrayList<TreeNode> filteredChildren = new ArrayList<TreeNode>();
        DefaultMutableTreeNode parentNode = null;
        parentNode = (DefaultMutableTreeNode)parent;
        for (Enumeration e=parentNode.children(); e.hasMoreElements();) {
            DefaultMutableTreeNode nextNode = (DefaultMutableTreeNode) e.nextElement();
            DefaultMutableTreeNode dummy = null;
              if (nextNode.children().hasMoreElements()) {
                  filteredChildren.add(nextNode);
            } else {
                // if node is leaf node
                if (filterText == null ) {
                    // add right away if no filter
                    filteredChildren.add(nextNode);
                } else {
                    // if filter matches this leaf node, add it. if not, how to check if
                    // parent nodes have empty children and remove it.
        return filteredChildren;
}i havent had luck the whole day trying to make this work. it seemed that once the filteredChildren.add() is called, it gets rendered to the treecellrenreder right away so if i wnat to remove the parents (in case it has no children based on the filter),the parent nodes will stay put in the jtree. any workaround? or ideas? i dont want to use a different defaulttreemodel for this. i want to avoid that because i have lots of nodes in my jtree.

Answer 1

Looks like you need this:
for (Enumeration e=parentNode.getFilteredChildren(); e.hasMoreElements();) Edit: okay, that was just a quick guess. Actually you're going to get into trouble if you try to recursively suppress nodes with no children. First you suppress all the leaf nodes (because they naturally don't have any children). Then you suppress all of their parents, because now they don't have any unsuppressed children. Then you suppress all of the parents' parents, because now they don't have any unsuppressed children... and so on until you only have the root left. So you need to refine that requirement.
But I get what you're saying. I had to do a similar thing, only I didn't use a FilteredTreeModel, I just built the TreeModel based on a selection from another tree. It's ridiculously hard to do when you don't get the nodes in order from the database, too, but that's a different problem.