Web Applications as Java Servlets
by Brad Cox


Listing One
package com.sdi.field;
import gnu.regexp.*;
public class Zipcode extends Field implements Validatable
{
  private final static RE re = re("\\d{5}([ -_]?\\d{4})?");
  private final static String msg = "A 5 or 9 digit zipcode is required";
  public final static Zipcode Null = new Zipcode(null);
public Zipcode(String value) { super(value); }
public boolean setValue(String v) 
{
  setValue(v, true, "");
  return requireNonNull() & requireMatch(re, msg);
}
}

Listing Two 
public class AddressBean extends BeanImpl
{
  private Identifier accountID = Identifier.Null;
  private Street street = Street.Null;
  private City city = City.Null;
  private USState state = USState.Null;
  private Zipcode zipcode = Zipcode.Null;
  private Phone phone = Phone.Null;

  public final static AddressBean Null = new AddressBean(
    Identifier.Null, Street.Null, City.Null, 
                     USState.Null, Zipcode.Null, Phone.Null
  );


Listing Three
public final void controller() throws Exception
{
  try
  {
    AccountBean thisAccount = (AccountBean)site.getAccount(this);
    redirect(DemoSite.Account);
    return; // should never happen
  }
  catch (SessionExpiredException e) { /* empty */ }

  Op op = (Op)getField("op", Op.Null);
  Identifier identifier = (Identifier)getField("identifier", Identifier.Null);

  if ( op.isValid() && identifier.isValid())
  {
    try
    {
      Connection connection = ConnectionPool.getConnection();
      AccountBean account = AccountBean.load(connection, identifier);
      site.setAccount(account, this);
      redirect(DemoSite.Account);
    }
    catch (Exception e)
    {
      identifier.setValid(false, "This identifier was not found");
      sendPage(viewLogin(identifier));
    }
  }
  else sendPage(viewLogin(identifier));
}

Listing Four
public void controller() throws Exception
{
  AccountBean thisAccount = (AccountBean)site.getAccount(this);
  AddressBean address = thisAccount.getAddress();

  Op op = (Op)getField("op", Op.Null);
  Street street = (Street)getField("street", address.getStreet());
  City city = (City)getField("city", address.getCity());
  USState state = (USState)getField("state", address.getState());
  Zipcode zipcode = (Zipcode)getField("zipcode", address.getZipcode());
  Phone phone = (Phone)getField("phone", address.getPhone());

  if ( op.isValid() && street.isValid() && city.isValid() &&
    state.isValid() && zipcode.isValid() && phone.isValid())
  {
    address.setAddress( street, city, state, zipcode, phone);
    address.save(thisAccount.getConnection());
    forward(DemoSite.Account);
  }
  else sendPage(viewAddress( op, street, city, state, zipcode, phone));
}

Listing Five 
public class DemoSite extends SiteImpl implements Site
{
  public static final Page Home = newStaticPage(
    "Home",
    null,
    Role.Null,
    "/html/index.htm",
    "Demo home page"
  );
  public final static DynamicPage Account = newDynamicPage(
    "Account",
    AccountView.class,
    "Account",
    Registered,
    "To your account"
  );
  public final static DynamicPage AccountRegistration = newDynamicPage(
    "AccountRegistration",
    AccountRegistrationView.class,
    "Registration",
    Role.Null,
    "Account Registration"
  );
  public final static DynamicPage EditAddress= newDynamicPage(
    "EditAddress",
    EditAddressView.class,
    "Address",
    Registered,
    "Modify your address and/or phone number"
  );
  public final static DynamicPage Login = newDynamicPage(
    "Login",
    LoginView.class,
    "Login",
    Role.Null,
    "Login procedure"
  );
  public final static DynamicPage Logout = newDynamicPage(
    "Logout",
    LogoutView.class,
    "Logout",
    Role.Null,
    "Logout"
  );
  public final static DynamicPage Refuse = newDynamicPage(
    "Refuse",
    RefuseView.class,
    "Permission Denied",
    Role.Null,
    "Permission denied"
  );
}

Listing Six 
public static AddressBean load(Connection connection, Identifier accountID)
  throws Exception
{
  String sql = "select * from DemoAddress " +
      "where accountID=\"" + accountID + "\"";
  try 
  {
    Statement stmt = connection.createStatement();
    ResultSet s = stmt.executeQuery(sql);
    if (!s.next())
      throw new Exception("couldn't do " + sql);

    return new AddressBean(
      accountID,
      new Street(s.getString("street")),
      new City(s.getString("city")),
      new USState(s.getString("state")),
      new Zipcode(s.getString("zipcode")),
      new Phone(s.getString("phone"))
    );
  } 
  catch (SQLException e) 
  {
    throw new Exception("SQLException in " + sql + "\n\t" + e);
  }
}

Listing Seven
public Identifier save(Connection connection) 
  throws Exception 
{
  String sql = "replace into DemoAddress set " +
    "accountID=?, " +
    "street=?, " +
    "city=?, " +
    "state=?, " +
    "zipcode=?, " +
    "phone=?";
  try 
  {
    PreparedStatement s = connection.prepareStatement(sql);
    s.setString(1, accountID.toString());
    s.setString(2, street.toString());
    s.setString(3, city.toString());
    s.setString(4, state.toString());

    s.setString(5, zipcode.toString());
    s.setString(6, phone.toString());
    
    int n = s.executeUpdate();
    s.close();
    return accountID;
  }
  catch (Throwable e)
  {
    throw new Exception("Throwable in " + sql + "\n\t" + e);
  }
}






4