UserFactorypublic class UserFactory extends Object | A class for creating new users in a database and retreiving existing users
from the database. Note that it assumes that a database table with the
specified name exists. You can create such a table with SQL like this:
CREATE TABLE subscribers (
email VARCHAR(64) PRIMARY KEY,
password VARCHAR(20),
html BIT,
digest BIT); |
| Fields Summary |
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| Connection | db | | String | tablename | | PreparedStatement | insertUser | | PreparedStatement | selectUser | | PreparedStatement | updateUser | | PreparedStatement | deleteUser |
| Constructors Summary |
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public UserFactory(Connection db, String tablename)
this.db = db;
this.tablename = tablename;
// Prepare the SQL statements we'll use later. Parameters will be
// subsituted for the question marks in the methods below.
insertUser = db.prepareStatement("insert into " + tablename +
"(email,password,html,digest) " +
"values(?,?,0,0)");
selectUser = db.prepareStatement("select * from " + tablename +
" where email=?");
deleteUser = db.prepareStatement("delete from " + tablename +
" where email=?");
updateUser = db.prepareStatement("update " + tablename +
" set html=?,digest=? where email=?");
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| Methods Summary |
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| public void | delete(User user)
if (user.deleted) return; // make sure we're not already deleted
// Delete the user from the database
deleteUser.setString(1, user.getEmailAddress());
deleteUser.executeUpdate();
user.deleted = true; // Don't allow update() after delete()
| | public User | insert(java.lang.String email, java.lang.String password)
// Check whether the user already exists
selectUser.setString(1, email);
ResultSet results = selectUser.executeQuery();
if (results.next()) throw new UserAlreadyExists(email);
// If not, create a new entry in the database
insertUser.setString(1, email);
insertUser.setString(2, password);
insertUser.executeUpdate();
// And return a matching User object to the caller
return new User(email, false, false);
| | public User | select(java.lang.String email, java.lang.String password)
// Look up the user
selectUser.setString(1, email);
ResultSet results = selectUser.executeQuery();
// Check that the user exists
if (!results.next()) throw new NoSuchUser(email);
// Check that the password is correct
String pw = results.getString("password");
if (!pw.equals(password)) throw new BadPassword(email);
// Return a User object representing this user and their mail prefs.
boolean html = results.getInt("html") == 1;
boolean digest = results.getInt("digest") == 1;
return new User(email, html, digest);
| | public void | update(User user)
if (user.deleted) return; // Don't allow updates to deleted users
// Update the database record to reflect new preferences
updateUser.setInt(1, user.getPrefersHTML()?1:0);
updateUser.setInt(2, user.getPrefersDigests()?1:0);
updateUser.setString(3, user.getEmailAddress());
updateUser.executeUpdate();
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