Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.util.HashMap;
import java.util.Stack;

import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.TreePath;

public class Main extends Box {
    public Main() {
        super(BoxLayout.Y_AXIS);
        DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
        for (int i = 0; i < 14; i++) {
            DefaultMutableTreeNode node = new DefaultMutableTreeNode("Root" + i);
            node.add(new DefaultMutableTreeNode("Child" + i));
            root.add(node);
        }
        CustomTree tree = new CustomTree(root);
        tree.setRootVisible(false);
        JScrollPane pane = new JScrollPane(tree);
        add(pane);
        JButton button = new JButton("Expand");
        button.addActionListener(e -> tree.expandSelectedPaths());
        add(button);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setContentPane(new Main());
        frame.validate();
        frame.pack();
        frame.setVisible(true);
    }
}

class CustomTree extends JTree {
    HashMap<TreePath, Boolean> expandedState = new HashMap<TreePath, Boolean>();
    Stack<TreePath> s = new Stack<TreePath>();

    public CustomTree(DefaultMutableTreeNode root) {
        super(root);
    }

    public void expandSelectedPaths() {
        TreePath[] paths = getSelectionPaths();
        if (paths == null || paths.length == 0) {
            return;
        }
        setSelectionPath(paths[0]);

        for (TreePath path : paths) {
            TreePath parentPath = path.getParentPath();

            while (parentPath != null) {
                if (isExpanded(parentPath)) {
                    parentPath = null;
                } else {
                    s.push(parentPath);
                    parentPath = parentPath.getParentPath();
                }
            }

            for (int i = s.size() - 1; i >= 0; i--) {
                parentPath = s.pop();
                if (!isExpanded(parentPath)) {
                    expandedState.put(parentPath, Boolean.TRUE);
                }
            }
        }

        if (accessibleContext != null) {
            ((AccessibleJTree) accessibleContext).fireVisibleDataPropertyChange();
        }

        for (TreePath path : paths) {
            fireTreeExpanded(path);
            try {
                fireTreeWillExpand(path);
            } catch (Exception eve) {
                return;
            }
        }
    }
}