users.java

JAVA Servlet2.3外文书籍源码

package forum;

import java.util.*;

/**
 * Represents all users in the discussion forum.
 * <p>
 * In a real system there would be a database containing the users.
 *
 * @author    Simon Brown
 */
public class Users {

  /** a collection of all users in the system */
  private static HashMap users = new HashMap();

  /**
   * Populates the collection of all users when the class is loaded.
   */
  static {
    User user;

    user = new User("Simon", "password");
    users.put(user.getId(), user);

    user = new User("Sam", "password");
    users.put(user.getId(), user);
  }

  /**
   * Determines whether a user with the specified id and password exists.
   *
   * @param id          a user id
   * @param password    a password
   * @return  true if a user exists in the system with the specified
   *          id and password, false otherwise
   */
  public static boolean exists(String id, String password) {
    User user = (User)users.get(id);

    return (user != null) && (user.getPassword().equals(password));
  }

  /**
   * Gets the user with the specified user id.
   *
   * @param id    a user id
   * @return  a User instance, could be null
   */
  public static User getUser(String id) {
    return (User)users.get(id);
  }

}