import java.awt.*;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class TreeDemo extends JFrame {
public TreeDemo() {
super("TreeDemo");
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
setSize(400, 400);
setLocationRelativeTo(null);
Tree tree = createDemoTree();
Node root = tree.getRoot();
root.moveTo(getSize().width / 2 - root.getBounds().width / 2, 20);
root.balanceX();
root.balanceY();
add(new TreeComponent(tree));
}
public static void main(final String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new TreeDemo().setVisible(true);
}
});
}
private Tree createDemoTree() {
Node root = new Node(new Person("Peter"));
Node n2 = new Node(new Person("Andrew"));
Node n3 = new Node(new Person("Paul"));
Node n5 = new Node(new Person("Jane"));
Node n8 = new Node(new Person("Bert"));
Node n9 = new Node(new Person("Big Blue"));
n9.setBounds(new Rectangle(0, 0, 100, 100));
Node n10 = new Node(new Person("Benny"));
root.addChild(n3);
root.addChild(n9);
n3.addChild(n2);
n3.addChild(n5);
n9.addChild(n8);
n9.addChild(n10);
return new Tree(root);
}
}
class TreeComponent extends JPanel {
private Tree tree;
public TreeComponent(final Tree tree) {
this.tree = tree;
}
@Override
public void paintComponent(final Graphics g) {
drawTree(g, tree.getRoot());
}
private void drawTree(final Graphics g, final Node node) {
((Graphics2D)g).setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
drawNode(g, node);
int numberOfChildren = node.numberOfChildren();
for (int i = 0; i < numberOfChildren; i++) {
drawTree(g, node.childNr(i));
}
}
private void drawNode(final Graphics g, final Node node) {
g.setColor(Color.BLACK);
g.drawRect(node.getBounds().x, node.getBounds().y,
node.getBounds().width, node.getBounds().height);
FontMetrics fm = getFontMetrics(getFont());
int i = fm.stringWidth(node.getElement().toString());
g.drawString(node.getElement().toString(), (node.getBounds().x
+ node.getBounds().width / 2) - (i / 2), node.getBounds().y
+ node.getBounds().height / 2);
g.setColor(Color.BLUE);
for (int j = 0; j < node.numberOfChildren(); j++) {
Node child = node.childNr(j);
g.drawLine(node.getBounds().x
+ node.getBounds().width / 2, node.getBounds().y
+ node.getBounds().height,
child.getBounds().x
+ child.getBounds().width / 2, child.getBounds().y);
}
}
}
class Node{
private Object data;
private List<Node> children;
private Rectangle bounds;
public Node(final Object o) {
data = o;
children = new ArrayList();
bounds = new Rectangle(0, 0, 50, 50);
}
public void addChild(final Node child) {
children.add(child);
}
public Object getElement() {
return data;
}
//
public Rectangle getBounds() {
return bounds;
}
public void setBounds(final Rectangle bounds) {
this.bounds = bounds;
}
public Node childNr(final int nr) {
return children.get(nr);
}
public int numberOfChildren() {
return children.size();
}
private int childrenWidth() {
int width = 0;
for (int i = 0; i < numberOfChildren(); i++) {
width += childNr(i).maxWidth();
if (i != numberOfChildren() - 1) {
width += 10;
}
}
return width;
}
private int maxWidth() {
int cWidth = childrenWidth();
if (cWidth > getBounds().width) {
return cWidth;
} else {
return getBounds().width;
}
}
public void balanceX() {
if (numberOfChildren() > 0) {
int cWidth = childrenWidth();
int middleX = getBounds().x + getBounds().width / 2;
int startX = middleX - cWidth / 2;
for (int i = 0; i < numberOfChildren(); i++) {
Node child = childNr(i);
int maxWidth = child.maxWidth();
int newX = (startX + maxWidth / 2) - child.getBounds().width / 2;
child.moveTo(newX, child.getBounds().y);
child.balanceX();
startX = startX + maxWidth + 10;
}
}
}
private void balanceY(final int height) {
int childHeight = 0;
int newY = getBounds().y + height + 20;
for (int i = 0; i < numberOfChildren(); i++) {
Node child = childNr(i);
if (child.getBounds().height > childHeight) {
childHeight = child.getBounds().height;
}
}
for (int i = 0; i < numberOfChildren(); i++) {
Node child = childNr(i);
child.moveTo(child.getBounds().x, newY);
child.balanceY(childHeight);
}
}
public void balanceY() {
balanceY(getBounds().height);
}
public void moveTo(final int newX, final int newY) {
getBounds().x = newX;
getBounds().y = newY;
}
}
class Tree {
private Node root;
public Tree(final Node root) {
this.root = root;
}
public Node getRoot() {
return root;
}
}
class Person{
private final String name;
public Person(final String name){
this.name = name;
}
@Override
public String toString(){
return name;
}
}
Mal im ernst: Es gibt Bibliotheken für sowas, JGraph, Jung & Co, die für allgemeine Graphen gedacht sind. Wenn es NUR um einen speziellen, kleinen Baum geht, und nicht 50 verschiedene Renderer, Färbungen, Interaktionen und LayoutManager verwendet werden sollen, könnte die Einarbeitung in so eine Lib aufwändiger sein, als es selbst schnell irgendwie hinzuschreiben.
