Java – how to draw a tree representing the connection node graph?

I want to display the tree in the Java GUI, but I don't know how The tree represents the graph of connected nodes, as shown below:

I should say I have my own tree class:

public class BinaryTree  
{
private BinaryNode root;
public BinaryTree( )
{
    root = null;
}

public BinaryTree( Object rootItem )
{
    root = new BinaryNode( rootItem,null,null );
}

public BinaryTree( Object rootItem,BinaryNode a,BinaryNode b )
{
    root = new BinaryNode( rootItem,a,b );
}

public int leavesCount(){
    return BinaryNode.leavesCount(root);
}

public boolean equal(BinaryTree a,BinaryTree b){
    return BinaryNode.equal(a.root,b.root);

}

public void printPreOrder( )
{
    if( root != null )
        root.printPreOrder( );
}

public void printInOrder( )
{
    if( root != null )
       root.printInOrder( );
}

public void printPostOrder( )
{
    if( root != null )
       root.printPostOrder( );
}

public void makeEmpty( )
{
    root = null;
}


public boolean isEmpty( )
{
    return root == null;
}


public void merge( Object rootItem,BinaryTree t1,BinaryTree t2 ) throws MergeAbrot
{
    if( t1.root == t2.root && t1.root != null )
    {
         throw new MergeAbrot("MergeAbrot");

    }

     root=new BinaryNode( rootItem,t1.root,t2.root );

    if( this != t1 )
        t1.root = null;
    if( this != t2 )
       t2.root = null;
}

public int size( )
{
    return BinaryNode.size( root );
}

public int height( )
{
    return BinaryNode.height( root );
}

}

I just want to draw trees What should I do?

Solution

The easiest way I can think of is to write a class that extends JPanel and overrides its paintcomponent () method In the paint method, you can traverse the tree and draw each node Here is a simple example:

import java.awt.Graphics;
import javax.swing.JFrame;
import javax.swing.JPanel;

public class JPanelTest extends JPanel {

    @Override
    public void paintComponent(Graphics g) {
        // Draw Tree Here
        g.drawOval(5,5,25,25);
    }

    public static void main(String[] args) {
        JFrame jFrame = new JFrame();
        jFrame.add(new JPaneltest());
        jFrame.setSize(500,500);
        jFrame.setVisible(true);
    }

}

Draw a thorn on the tree if you can't figure out what you tried on your problem