librarysystem.java

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import java.io.*; /*!Begin Snippet:file*/
import java.util.*;

/**
 * This class implements a sample of the library system.
 *
 * @author author name
 * @version 1.1.0
 * @see CatalogItem
 * @see Book
 * @see Recording
 * @see Catalog
 * @see Borrower
 * @see BorrowerDatabase
 * @see BorrowersFormatter
 * @see PlainTextBorrowersFormatter
 * @see HTMLBorrowersFormatter
 * @see XMLBorrowersFormatter
 * @see LibraryCatalogLoader
 * @see FileLibraryCatalogLoader
 */
public class LibrarySystem  {

    private static BufferedReader  stdIn =
        new  BufferedReader(new  InputStreamReader(System.in));
    private static PrintWriter  stdOut =
        new  PrintWriter(System.out, true);
    private static PrintWriter  stdErr =
        new  PrintWriter(System.err, true);

    private Catalog  catalog;

    private BorrowerDatabase borrowerDB;

    private BorrowersFormatter borrowersFormatter;

    /**
     * Loads a library catalog and borrower database from a file
     * and then starts the application.
     * <p>
     * The name of the file is specified in the command arguments
     * </p>
     *
     * @param args  String arguments.
     * @throws IOException if there are errors in the input.
     */
    public static void  main(String[]  args) throws IOException {

        if (args.length != 1) {
            stdErr.println("Usage: java LibrarySystem filename");
        } else {

            Catalog catalog = null;

            try {

                LibraryCatalogLoader loader =
                    new FileLibraryCatalogLoader();

                catalog = loader.loadCatalog(args[0]);
            } 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);
            }

            LibrarySystem  app = new LibrarySystem(catalog);

            app.run();
        }
    }

    /*
     * Constructs a <code>LibrarySystem</code> object.
     * Initialize the catalog and borrower database with
     * the values specified in the parameter.
     */
    private LibrarySystem(Catalog initialCatalog) {

        catalog = initialCatalog;
        borrowerDB = loadBorrowers(catalog);
        borrowersFormatter =
            PlainTextBorrowersFormatter.getSingletonInstance();
    }

    /*
     * Loads a BorrowerDatabase object.
     */
    private BorrowerDatabase loadBorrowers(Catalog catalog) {

        BorrowerDatabase borrowerDB = new BorrowerDatabase();

        Borrower borrower = new Borrower("ID001", "James Addy");

        borrower.getBorrowedItems().addItem(
            catalog.getItem("B003"));
        borrower.getBorrowedItems().addItem(
            catalog.getItem("R001"));
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B012"));
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID002", "John Doust");
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID003", "Constance Foster");
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B006"));
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID004", "Harold Gurske");
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B002"));
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID005", "Mary A. Rogers");
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID006", "Laura Novelle");
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B007"));
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B009"));
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID007", "David M. Prescott");
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B011"));
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID008", "Francis Matthews");
        borrower.getBorrowedItems().addItem(
            catalog.getItem("R003"));
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B005"));
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID009", "Thomas Ferris");
        borrowerDB.addBorrower(borrower);

        borrower = new Borrower("ID010", "John Johnson");
        borrower.getBorrowedItems().addItem(
            catalog.getItem("B004"));
        borrowerDB.addBorrower(borrower);

        return borrowerDB;
    }

    /*
     * Presents user with menu of options and executes selected task.
     */
    private void run() throws IOException  {

        int  choice = getChoice();

        while (choice != 0)  {
            if (choice == 1)  {
                displayCatalog();
            } else if (choice == 2)  {
                borrowersFormatter =
                    PlainTextBorrowersFormatter.getSingletonInstance();
                writeFile(readFileName(),
                          borrowersFormatter.formatBorrowers(borrowerDB));
            } else if (choice == 3)  {
                borrowersFormatter =
                    HTMLBorrowersFormatter.getSingletonInstance();
                writeFile(readFileName(),
                          borrowersFormatter.formatBorrowers(borrowerDB));
            } else if (choice == 4)  {
                borrowersFormatter =
                    XMLBorrowersFormatter.getSingletonInstance();
                writeFile(readFileName(),
                          borrowersFormatter.formatBorrowers(borrowerDB));
            }

            choice = getChoice();
        }
    }

    /*
     * Displays a menu of options and verifies the user's choice.
     */
    private int  getChoice() throws IOException  {

        int  input;

        do  {
            try  {
                stdErr.println();
                stdErr.print("[0]  Quit\n"
                             + "[1]  Display catalog\n"
                             + "[2]  Save borrower database (plain text)\n"
                             + "[3]  Save borrower database (HTML)\n"
                             + "[4]  Save borrower database (XML)\n"
                             + "choice> ");
                stdErr.flush();

                input = Integer.parseInt(stdIn.readLine());

                stdErr.println();

                if (0 <= input && 4 >= input)  {
                    break;
                } else {
                    stdErr.println("Invalid choice:  " + input);
                }
            } catch (NumberFormatException  nfe)  {
                stdErr.println(nfe);
            }
        }  while (true);

        return  input;
    }

    /*
     * Displays the catalog.
     */
    private void displayCatalog() {

        int numberOfItems = this.catalog.getNumberOfItems();

        if (numberOfItems == 0) {
            stdErr.println("The catalog is empty");
        } else {
            for (Iterator i = catalog.getItemsIterator();
                    i.hasNext();) {

                CatalogItem item = (CatalogItem) i.next();

                stdOut.println(item.getCode() + " "
                               + item.getTitle() + " " +
                               (item.isAvailable()? "(A)" : "(NA)"));
            }
        }
    }

    /*
     * Prompts the user for a file name (the name of the file that
     * will store the borrower database) and returns the user's
     * response.
     */
    private  String readFileName() throws IOException  {

        stdErr.print("File name> ");
        stdErr.flush();

        return stdIn.readLine();
    }

    /*
     * Creates a new file (which has the specified name) and writes
     * the specified string to the new file
     */
    private void writeFile(String fileName, String content)
    throws IOException {

        PrintWriter fileOut =
            new PrintWriter(new FileWriter(fileName));

        fileOut.println(content);

        fileOut.close();
    }
}