How not to display a directory in the TreeView that does not contain the required file?

Question

Java

It is necessary to search the file system for files with a certain extension and display in the form of a tree the directory in which these files are located. The code to display the entire directory was not difficult, the question is how to adapt it to the task?
Search button

@FXML
    public void findInDirectory(){
        DirectoryChooser directoryChooser = new DirectoryChooser(); 
        directoryChooser.setInitialDirectory(new File(System.getProperty("user.home")));
        File choice = directoryChooser.showDialog(primaryStage);
        if(choice == null || ! choice.isDirectory()) {
            Alert alert = new Alert(Alert.AlertType.ERROR);
            alert.setHeaderText("Could not open directory");
            alert.setContentText("The file is invalid.");

            alert.showAndWait();
        } else {
            treeView.setRoot(getNodesForDirectory(choice));
        }
    }

Building a tree

public TreeItem<String> getNodesForDirectory(File directory) { 
        TreeItem<String> root = new TreeItem<>(directory.getName());
        for(File f : directory.listFiles()) {
            System.out.println("Loading " + f.getName());
            if(f.isDirectory()) { 
                root.getChildren().add(getNodesForDirectory(f));
            } else {

                root.getChildren().add(new TreeItem<>(f.getName()));

            }
        }
        return root;
    }