ssd3 exercise7 答案

import java.awt.*; import java.awt.event.*; import javax.swing.*; import javax.swing.event.*; import java.io.*; /** * This class displays the catalog of the gourmet coffee system. * * @author author name * @version 1.1.0 * @see Product * @see Coffee * @see CoffeeBrewer * @see Catalog * @see CatalogLoader * @see FileCatalogLoader * @see DataFormatException */ public class CatalogGUI extends JPanel { /* Standar error stream */ static private PrintWriter stdErr = new PrintWriter(System.err, true); /* Window width in pixels */ static private int WIDTH = 380; /* Window height in pixels */ static private int HEIGHT = 320; /* Size of the list cell in pixels */ static private int CELL_SIZE = 50; /* Visible rows in list */ static private int LIST_ROWS = 10; /* Rows in status text area */ static private int STATUS_ROWS = 5; /* Rows in status text area */ static private int STATUS_COLS = 40; private JList catalogList; private JPanel productPanel; private JTextArea statusTextArea; private Catalog catalog; /** * Loads a product catalog and starts the application. * * @param args String arguments. Not used. * @throws IOException if there are errors in the loading the catalog. */ public static void main(String[] args) throws IOException { String filename = ""; if (args.length != 1) { filename = "catalog.dat"; } else { filename = args[0]; } try { Catalog catalog = (new FileCatalogLoader()).loadCatalog(filename); JFrame frame = new JFrame("Catalog Gourmet Coffee"); frame.setContentPane(new CatalogGUI(catalog)); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(WIDTH, HEIGHT); frame.setResizable(true); frame.setVisible(true); } catch (FileNotFoundException fnfe) { stdErr.println("The file does not exist"); System.exit(1); } catch (DataFormatException dfe) { stdErr.println("The file contains malformed data: " + dfe.getMessage()); System.exit(1); } } /** * Instantiates the components and arranges them in a window. * * @param initialCatalog a product catalog. */ public CatalogGUI(Catalog initialCatalog) { catalog = initialCatalog; // create the components catalogList = new JList(catalog.getCodes()); catalogList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION); catalogList.setVisibleRowCount(LIST_ROWS); catalogList.setFixedCellWidth(CELL_SIZE); statusTextArea = new JTextArea(STATUS_ROWS, STATUS_COLS); statusTextArea.setEditable(false); // create product information panel productPanel = new JPanel(); productPanel.setBorder( BorderFactory.createTitledBorder("Product Information")); // create panel to hold list and Display button JPanel catalogPanel = new JPanel(); catalogPanel.setBorder(BorderFactory.createTitledBorder("Catalog")); catalogPanel.add( new JScrollPane(catalogList, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER)); setLayout(new BorderLayout()); add(catalogPanel, BorderLayout.WEST); add(productPanel, BorderLayout.CENTER); add(statusTextArea, BorderLayout.SOUTH); // start listening for list-selection events catalogList.addListSelectionListener(new CatalogListListener()); } /** * This inner class handles list-selection events. */ class CatalogListListener implements ListSelectionListener { /** * Displays the information of the selected product. * * @param event the event object. */ public void valueChanged(ListSelectionEvent event) { String code = (String) catalogList.getSelectedValue(); Product product = catalog.getProduct(code); productPanel.removeAll(); productPanel.setVisible(false); // Use this productPanel.add(product.getPanel()); // to update the productPanel.setVisible(true); // panel correctly statusTextArea.setText("Product " + code + " has been displayed"); } } }