loginhelper.java

ORACLE AQ sample 演示的如何出列

package oracle.otnsamples.AQ.Helper;

/**
 * @author  Rajat Gupta
 * @version 1.0
 *
 * Name of the Application        :  LoginHelper.java
 * Development Environment        :  Oracle 9i JDeveloper
 * Creation/Modification History  :
 *
 *    Rajat Gupta       15-Jan-2001      Created
 *
 */

// Util Imports
import java.util.Hashtable;
import java.util.Vector;

// Other files
import oracle.otnsamples.AQ.DataBase.DBConnect;

/**
 * This class helps in logging a customer or an admin. It checks if the provided
 * UserName/Password is valid or not.
 * If the user is valid, then the Name of the User is returned.
 * If the user is not valid, then an exception is generated and the proper error
 * message is shown to the User.
 */
public class LoginHelper{

  /**
   * Empty Constructor
   */
  public LoginHelper(){
  }

  /**
   * This method validates the User (Customer/Admin) entered. It takes as input parameters the
   * loginID, password of User and also the type of User. An Exception is thrown
   * on invalid login/password.
   *
   * @param p_login Login ID entered by the User
   * @param p_password Password entered by the User
   * @param p_user Type of User
   * @exception Exception if User is not valid
   * @return If valid User, then the Name of the User is returned
   * @see DBConnect.java
   */
  static public Hashtable validateUser(String p_login, String p_password, String p_user)
                                                                       throws Exception{
    Hashtable userinfo = new Hashtable();
    Vector data = null;
    String query = "";

    // Gets the Instance of DBConnect
    DBConnect dbInstance = DBConnect.getInstance();

    if (p_user.equals("Customer")){

      // If the user is of type customer then validate him using the Customer_Master table.
      query = "SELECT INITCAP(customer_name) FROM Customer_Master WHERE"
                  +" LOWER(TRIM(customer_id)) = LOWER(TRIM('"+ p_login +"'))"
                    + " AND LOWER(password) = LOWER('"+ p_password + "')";

    }else if ((p_user.equals("Computer")) || (p_user.equals("Printer"))
        || (p_user.equals("Retail"))){

      // If the user is of type Computer or Printer or Retail then validate
      // him using the Admin_Master table.
      query = "SELECT INITCAP(admin_name) FROM Admin_Master WHERE"
                  +" LOWER(TRIM(admin_id)) = LOWER(TRIM('"+ p_login +"')) AND"
                    +" LOWER(admin_password) = LOWER('"+ p_password + "')";

    }


    // Get the data from the resultset in the form of a String array
    // stored in Vector.
    data = dbInstance.executeQuery(query, p_user);

    // Validate the user.
    isValid(data);

    // Get the userName and store it in a Hashtable.
    String[] userName = (String[])data.elementAt(0);
    userinfo.put("Name",userName[0]);

    return userinfo;
  }

  /**
   * This method checks is the User is valid or not. If the Size of the Vector
   * passed is 1, then an entry is matched for the particular Username/Password
   * in the database. If the size of Vector is 0 or more than 1, then the User
   * is not valid and an exception is thrown.
   *
   * @exception Exception thrown if the Username/Password provided is invalid
   * @param p_data Vector Passed that Contains the Name of the User if valid
   */
  private static void isValid(Vector p_data) throws Exception{
    if (p_data.size() != 1){
      throw new Exception("AQ-1000");
    }
  }
}