databaseapplication.java

Java the UML Way 书中所有源码

/*
 * DatabaseApplication.java  E.L. 2001-08-26
 *
 * The primary window in this GUI application shows all the data in the person table.
 * The user may choose to update data, delete data or add new data to the database.
 * If updates were accepted by the database, they are also reflected in the primary window.
 * To reflect database updates done by other users, the user has to click on
 * the "Refresh" button.
 */

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.text.*;
import myLibrary.*;

class DatabaseGUI extends JFrame {
  private Database theDatabaseContact;

  private Container guiContainer;
  private DefaultListModel listData = new DefaultListModel();
  private JList list = new JList(listData);

  private JButton deleteButton = new JButton("Delete");
  private JButton newButton = new JButton("New");
  private JButton editButton = new JButton("Edit");
  private JButton refreshButton = new JButton("Refresh");

  private PersonDialog personDialog = new PersonDialog(this);

  public DatabaseGUI(Database initDatabase) {
    theDatabaseContact = initDatabase;

    setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
    addWindowListener(new WindowClosingListener());

    guiContainer = getContentPane();
    guiContainer.add(
      new HeadingPanel("Name Archive"), BorderLayout.NORTH);
    guiContainer.add(new ListPanel(), BorderLayout.CENTER);
    guiContainer.add(new ButtonPanel(), BorderLayout.SOUTH);

    fillListWithData();  // see below.
    personDialog.setLocation(300, 400);
    setLocation(300, 300);
    pack();
  }

  /* Help method: Retrieves data from the database and fills the list in the primary window.*/
  private void fillListWithData() {
    try {
      listData.clear();
      ArrayList all = theDatabaseContact.getAll();
      for (int i = 0; i < all.size(); i++) listData.addElement(all.get(i));
      if (listData.size() > 0) list.setSelectedIndex(0); // default selection
      else { // no data, the Edit and Delete buttons should be locked
        deleteButton.setEnabled(false);
        editButton.setEnabled(false);
      }
    } catch (Exception e) {
      JOptionPane.showMessageDialog(null, "Error retrieving data.\n" + e);
    }
  }

  /*
   * Here follow the three panels describing the user interface.
   */
  private class HeadingPanel extends JPanel {
    public HeadingPanel(String heading) {
      Font defFont = getFont();
      Font bigFont = new Font(defFont.getName(), defFont.getStyle(), 18);
      JLabel text = new JLabel(heading);
      text.setFont(bigFont);
      add(text);
    }
  }

  private class ListPanel extends JPanel {
    public ListPanel() {
      list.setPreferredSize(new Dimension(300, 300)); // FlowLayout allows for this
      list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
      JScrollPane scrollWithList = new JScrollPane(list);

      /* List heading */
      JViewport jvp = new JViewport(); // see online API doc.
      jvp.setView(new JLabel("All Names"));
      scrollWithList.setColumnHeader(jvp);

      add(scrollWithList);
    }
  }

  private class ButtonPanel extends JPanel {
    public ButtonPanel() {
      ButtonListener theListener = new ButtonListener();
      deleteButton.addActionListener(theListener);
      newButton.addActionListener(theListener);
      editButton.addActionListener(theListener);
      refreshButton.addActionListener(theListener);
      add(deleteButton);
      add(newButton);
      add(editButton);
      add(refreshButton);
    }
  }

  /*
   * This class handles all the button clicks.
   */
  private class ButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent event) {
      JButton source = (JButton) event.getSource();

      if (source == deleteButton) {  // Deletes a person
        Person thePerson = (Person) list.getSelectedValue();
        try {
          boolean deleted = theDatabaseContact.deletePerson(thePerson.getPersIdent());
          if (deleted) {
            listData.remove(list.getSelectedIndex());
            if (listData.size() == 0) {
              deleteButton.setEnabled(false);
              editButton.setEnabled(false);
            }
            else list.setSelectedIndex(0);
          } else {
            JOptionPane.showMessageDialog(null, "Not possible to delete this person." +
                                          "Other clients may have done it already.");
          }
        } catch (Exception e) {
          JOptionPane.showMessageDialog(null, "Error when deleting: " + e);
        }
      }

      else if (source == editButton) {  // updates a name
        Person thePerson = (Person) list.getSelectedValue();
        int index = list.getSelectedIndex();
        if (personDialog.showDialog(thePerson)) {  // thePerson object will be updated
          try {
            if (theDatabaseContact.updateName(thePerson)) {
              listData.set(index, thePerson);  // updates the list in the window
              list.setSelectedIndex(0);
            } else JOptionPane.showMessageDialog(null,
                     "No data updated. The person may be deleted by others.");
          } catch (Exception e) {
            JOptionPane.showMessageDialog(null, "Error when changing data: " + e);
          }
        }
      }

      else if (source == newButton) {  // Stores new person.
        Person thePerson = new Person(-1,"", "");
        if (personDialog.showDialog(thePerson)) {
          try {
            thePerson = theDatabaseContact.registerNewPerson(
               thePerson.getFirstName(), thePerson.getLastName());
            JOptionPane.showMessageDialog(null,
                            "The person gets ident. no. " + thePerson.getPersIdent());
            listData.addElement(thePerson);
            if (listData.size() == 1) { // this was the first person in the database!
              deleteButton.setEnabled(true);
              editButton.setEnabled(true);
              list.setSelectedIndex(0);
            }
          } catch (Exception e) {
              JOptionPane.showMessageDialog(null, "Error storing data: " + e);
          }
        }
      }

      else if (source == refreshButton) { // Refreshes the data in the list
        fillListWithData();
      }
    }
  }

  private class WindowClosingListener extends WindowAdapter {
    public void windowClosing(WindowEvent event) {
      listData.clear(); // empties the list
      try {
        theDatabaseContact.closeTheConnection();
      } catch (Exception e) {
        System.out.println("Error when disconnecting: " + e);
      }
      System.exit(0);
    }
  }
}

class DatabaseApplication {
  public static void main(String[] args) {
    Database theDatabaseContact = null;
    try {
      String userName = JOptionPane.showInputDialog("User Name: ");
      String password = JOptionPane.showInputDialog("Password: ");
      theDatabaseContact = new Database(userName, password);
    } catch (Exception e) {
      JOptionPane.showMessageDialog(null,
        "Problems when establishing database connection, " +
        "the user name or the password may be invalid. \nError: " + e);
      try {
        theDatabaseContact.closeTheConnection(); // disconnects what may be disconnected
      } catch (Exception e1) {
      }
      System.exit(0);
    }
    DatabaseGUI theApplication = new DatabaseGUI(theDatabaseContact);
    theApplication.setVisible(true);
  }
}