BINARY SEARCH TREES - Introduction to Java Programming: Comprehensive Version - page 950

27 tfKey, btInsert, btDelete);
28 hBox.setAlignment(Pos.CENTER);
29 pane.setBottom(hBox);
30
31 btInsert.setOnAction(e -> {
32 int key = Integer.parseInt(tfKey.getText());
33 if (tree.search(key)) { // key is in the tree already
34 view.displayTree();
35 view.setStatus(key + " is already in the tree" );
36 } else {
37 tree.insert(key); // Insert a new key
38 view.displayTree();
39 view.setStatus(key + " is inserted in the tree" );
40 }
41 });
42
43 btDelete.setOnAction(e -> {
44 int key = Integer.parseInt(tfKey.getText());
45 if (!tree.search(key)) { // key is not in the tree
46 view.displayTree();
47 view.setStatus(key + " is not in the tree" );
48 } else {
49 tree.delete(key); // Delete a key
50 view.displayTree();
51 view.setStatus(key + " is deleted from the tree" );
52 }
53 });
54
55 // Create a scene and place the pane in the stage
56 Scene scene = new Scene(pane, 450 , 250 );
57 primaryStage.setTitle( "BSTAnimation" ); // Set the stage title
58 primaryStage.setScene(scene); // Place the scene in the stage
59 primaryStage.show(); // Display the stage
60 }
61 }

place hBox

handle insertion

insert key
display the tree

handle deletion

delete key
display the tree

L ISTING 25.10

BTView.java
1 import javafx.scene.layout.Pane;
2 import javafx.scene.paint.Color;
3 import javafx.scene.shape.Circle;
4 import javafx.scene.shape.Line;
5 import javafx.scene.text.Text;
6
7 public class BTView extends Pane {
8

private BST<Integer> tree = new BST<>(); tree to display

9 private double radius = 15 ; // Tree node radius

10 private double vGap = 50 ; // Gap between two levels in a tree

11
12 BTView(BST<Integer> tree) {
13 this .tree = tree;
14 setStatus( "Tree is empty" );
15 }
16
17 public void setStatus(String msg) {
18 getChildren().add( new Text( 20 , 20 , msg));
19 }
20

set a tree