Почему я продолжаю получать сообщение об ошибке «Не могу найти символ» ⇐ JAVA

[Anonymous]

Я пытаюсь сохранить в массиве один из трех элементов: книгу, компакт-диск или DVD, но мой метод добавления не работает.
вот класс GUI.
/**
Class BookStoreApplication GUI represents a book store.
It gives the user the option to
- add a book to the store's inventory
- list all books in the store's inventory

Author: YOUR FULL NAME HERE
E-mail address: YOUR E-MAIL ADDRESS
Last changed: TODAY'S DATE
Lab 01
*/

import javafx.application.Application;
import javafx.scene.Scene;
import javafx.stage.Stage;

import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.control.RadioButton;
import javafx.scene.control.ToggleGroup;
import javafx.scene.control.TextArea;

import javafx.scene.layout.GridPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.VBox;
import javafx.scene.layout.BorderPane;

import javafx.geometry.Pos;

import javafx.event.ActionEvent;
import javafx.event.EventHandler;

public class BookStoreGUI extends Application {

private String title;
private String author;
private double price;
private static int pages;
private static int playingTime;

private Label titleLabel;
private Label authorLabel;
private Label priceLabel;

private TextField titleTextField;
private TextField authorTextField;
private TextField priceTextField;

private GridPane inputGrid;

private RadioButton BookRadioButton;
private RadioButton CDRadioButton;
private RadioButton DVDRadioButton;

private VBox RadioVBox;

private ToggleGroup mediaGroup;

private Button addItemButton;
private Button displayInventoryButton;

private HBox buttonHBox;

private TextArea outputText;

private BookStoreHandler handler;

private Stage maessageWindow;

private GridPane topGrid;

private BorderPane mainPane;

private static int count = 0;

private static BookStoreItem[] Catalog;

public void start(Stage primaryStage) {

createInputComponents();
createOutputComponents();
createButtons();
createWindow();

Scene scene = new Scene(mainPane, 400, 500);

primaryStage.setTitle("Book Sotre");

primaryStage.setScene(scene);

primaryStage.show();
}

private void createInputComponents(){

titleLabel = new Label("Title");
authorLabel = new Label("Author's name");
priceLabel = new Label ("Price");

titleTextField = new TextField();
authorTextField = new TextField();
priceTextField = new TextField();

inputGrid = new GridPane();
inputGrid.setHgap(15);
inputGrid.setVgap(15);

inputGrid.add(titleLabel, 0 , 0);
inputGrid.add(titleTextField, 1, 0);
inputGrid.add(authorLabel, 0, 1);
inputGrid.add(authorTextField, 1, 1);
inputGrid.add(priceLabel, 0 , 2);
inputGrid.add(priceTextField, 1, 2);

CDRadioButton = new RadioButton("CD");
BookRadioButton = new RadioButton("Book");
DVDRadioButton = new RadioButton("DVD");

mediaGroup = new ToggleGroup();

CDRadioButton.setToggleGroup(mediaGroup);
BookRadioButton.setToggleGroup(mediaGroup);
DVDRadioButton.setToggleGroup(mediaGroup);

BookRadioButton.setSelected(true);
RadioVBox = new VBox(15);

RadioVBox.getChildren().add(CDRadioButton);
RadioVBox.getChildren().add(BookRadioButton);
RadioVBox.getChildren().add(DVDRadioButton);

topGrid = new GridPane();
topGrid.setHgap(20);
topGrid.setAlignment(Pos.CENTER);

topGrid.add(inputGrid, 0, 0);
topGrid.add(RadioVBox, 1, 0);

}
private void createOutputComponents () {

outputText = new TextArea();

outputText.setEditable(false);
}

private void createButtons() {

addItemButton = new Button("Add Item");
displayInventoryButton = new Button("Display Inventory");

addItemButton.setPrefSize(100, 50);
displayInventoryButton.setPrefSize(100, 50);

buttonHBox = new HBox(100);

buttonHBox.setAlignment(Pos.CENTER);

buttonHBox.getChildren().add(addItemButton);
buttonHBox.getChildren().add(displayInventoryButton);

handler = new BookStoreHandler();

addItemButton.setOnAction(handler);
displayInventoryButton.setOnAction(handler);
}

private void createWindow() {

mainPane = new BorderPane();

mainPane.setTop(topGrid);
mainPane.setCenter(outputText);
mainPane.setBottom(buttonHBox);
}

private class BookStoreHandler implements EventHandler {
public void handle(ActionEvent ae) {
BookStoreItem media;
if(ae.getSource () == addItemButton){
outputText.setText("");

title = titleTextField.getText().trim();
author = authorTextField.getText().trim();
price = Double.parseDouble(priceTextField.getText().trim());

if (CDRadioButton.isSelected()){
media = new CD(title, author, price, 0);

}
else if(DVDRadioButton.isSelected()) {
media = new DVD(title, author, price, 0);
}
else {
media = new Book(title, author, price, 0);
}

Catalog = Catalog.add(media);

}

}
}
}

вот мое сообщение об ошибке:
BookStoreGUI.java:210: error: cannot find symbol
Catalog = Catalog.add(media);
^
symbol: method add(BookStoreItem)
location: variable Catalog of type BookStoreItem
1 error

а вот класс каталога, из которого взят метод add.
public class Catalog {

private BookStoreItem[] inventory;
private final int CAPACITY = 100;
private int count;

public Catalog() {
inventory = new BookStoreItem[CAPACITY];
count = 0;
}

public void add(BookStoreItem newItem) {
inventory[count] = newItem;
count++;
}

public boolean isAvailable(String title) {

boolean found = false;

for (int i = 0;i < count && !found;i++) {
if (title.equals(inventory.getTitle())) {
found = true;
}
}

return found;
}

public BookStoreItem getItem(String title) {

BookStoreItem desiredItem = null;

boolean found = false;

for (int i = 0;i < count && !found;i++) {
if (title.equals(inventory.getTitle())) {
desiredItem = inventory;
found = true;
}
}

return desiredItem;

}

public BookStoreItem[] getList() {
return inventory;
}

}



Подробнее здесь: https://stackoverflow.com/questions/333 ... mbol-error