managerfactory.java

基于struts框架编写的在线考试系统

package examonline.service;

/**
 * <p>Title: </p>
 *
 * <p>Description: examonline</p>
 *
 * <p>Copyright: Copyright (c) 2008</p>
 *
 * <p></p>
 *
 * @author 
 * @version 1.0
 */
public class ManagerFactory
{
  private ManagerFactory()
  {
  }

  /**
   * 用户管理的实现类，默认为ACCESS数据库存储
   */
  public  static final String USERMANAGER_IMPL_CLASS = "";
  public static final String DEFAULT_USERMANAGER_IMPL_CLASS =
      "examonline.service.impl.DefaultUserDAOImpl";

  /**
   * 试题管理的实现类，默认为ACCESS数据库存储
   */
  public static final String QUESTIONMANAGER_IMPL_CLASS = "";
  public static final String DEFAULT_QUESTIONMANAGER_IMPL_CLASS =
      "examonline.service.impl.DefaultQuestionDAOImpl";
  /**
   * 分类管理的实现类，默认为ACCESS数据库存储
   */
  public static final String TYPEMANAGER_IMPL_CLASS = "";
  public static final String DEFAULT_TYPEMANAGER_IMPL_CLASS =
      "examonline.service.impl.DefaultTypeDAOImpl";
  /**
   * 试题管理的实现类，默认为STRUTS数据库连接池提供的数据源
   */
  public static final String DBMANAGER_IMPL_CLASS = "";
  public static final String DEFAULT_DBMANAGER_IMPL_CLASS =
       "examonline.service.impl.DefaultDBManagerImpl";

  /**
   * 考生答题情况管理的实现类，默认为ACCESS数据库存储
   */
  public static final String EXAMMANAGER_IMPL_CLASS = "";
  public static final String DEFAULT_EXAMMANAGER_IMPL_CLASS =
      "examonline.service.impl.DefaultExamRecordDAOImpl";

  public static UserDAO um = null;
  public static QuestionDAO qm = null;
  public static DBManager dm = null;
  public static ExamRecordDAO em = null;
  public static TypeDAO tm = null;

  /**
   * 获取用户管理实现类
   */
  public static UserDAO getUserManager()
  {

    try
    {
      if (um != null)
        return um;

      if (!"".equals(USERMANAGER_IMPL_CLASS))
      {
        um = (UserDAO) Class.forName(USERMANAGER_IMPL_CLASS).newInstance();
      }
      else
        um = (UserDAO) Class.forName(DEFAULT_USERMANAGER_IMPL_CLASS).
            newInstance();
    }
    catch (Exception ex)
    {
      ex.printStackTrace();
    }

    return um;
  }

  public static QuestionDAO getQuestionManager()
  {

    try
    {
      if(qm!=null)
        return qm;
      if (!"".equals(QUESTIONMANAGER_IMPL_CLASS))
        qm = (QuestionDAO) Class.forName(QUESTIONMANAGER_IMPL_CLASS).
            newInstance();
      else
        qm = (QuestionDAO) Class.forName(
            DEFAULT_QUESTIONMANAGER_IMPL_CLASS).newInstance();
    }
    catch (Exception ex)
    {
      ex.printStackTrace();
    }

    return qm;
  }

  public static TypeDAO getTypeManager()
  {

    try
    {
      if(tm!=null)
        return tm;
      if (!"".equals(TYPEMANAGER_IMPL_CLASS))
        tm = (TypeDAO) Class.forName(TYPEMANAGER_IMPL_CLASS).
            newInstance();
      else
        tm = (TypeDAO) Class.forName(
            DEFAULT_TYPEMANAGER_IMPL_CLASS).newInstance();
    }
    catch (Exception ex)
    {
      ex.printStackTrace();
    }

    return tm;
  }

  
  public static DBManager getDBManager()
  {

    try
    {
      if(dm!=null)
        return dm;
      if (!"".equals(DBMANAGER_IMPL_CLASS))
      {
        dm = (DBManager) Class.forName(USERMANAGER_IMPL_CLASS).newInstance();
      }
      else
        dm = (DBManager) Class.forName(DEFAULT_DBMANAGER_IMPL_CLASS).
            newInstance();
    }
    catch (Exception ex)
    {
      ex.printStackTrace();
    }

    return dm;

  }

  public static ExamRecordDAO getExamRecordManager()
  {
    try
   {
     if(em!=null)
       return em;
     if (!"".equals(EXAMMANAGER_IMPL_CLASS))
     {
       em = (ExamRecordDAO) Class.forName(EXAMMANAGER_IMPL_CLASS).newInstance();
     }
     else
       em = (ExamRecordDAO) Class.forName(DEFAULT_EXAMMANAGER_IMPL_CLASS).
           newInstance();
   }
   catch (Exception ex)
   {
     ex.printStackTrace();
   }

   return em;

  }

}