java – 无法使用多态访问具体类的唯一属性

我面临的问题是每个具体类将具有该特定类的唯一属性.由于工厂在返回具体类的实例时将使用多态性,因此无法访问唯一属性.即getHostType()仅对SqlServerConnection是唯一的.

我所做的解决方法是在超类中声明getHostType()抽象并在每个具体类中实现它.但是,我真的不想这样做,因为我添加的更具体的类具有它们的唯一属性,我将必须包含在超类中的更抽象的方法,然后在每个具体类中实现它们.

我想保留我的工厂模式和抽象的超级课程.我只是想知道是否有其他方法而不是超类中的抽象方法？我可以包括任何设计模式来解决这个问题？

public abstract class Connection {
    private int port;
    private int ipAddress;

    public Connection() {}

    public String description() {
        return "Generic";
    }

    /* Implement in every concrete class,even if the concrete type doesn't have that property */
    public abstract int getHostType();
}

public class SqlServerConnection extends Connection {
    private int sqlHostType;

    public SqlServerConnection() {
        sqlHostType = 5060;
    }

    @Override
    public String description() {
        return "Created a Sql Server connection type";
    }

    @Override
    public int getHostType() {
        return sqlHostType;
    }
}

public class OracleConnection extends Connection {
    public OracleConnection() {}

    @Override
    public String description() {
        return "Created an Oracle connection type";
    }
}

final public class ConnectionFactory {
    protected String mType;

    public ConnectionFactory(String type) {
        mType = type;
    }

    /* Create the connection we want to use */
    public Connection createConnection() {
        if(mType.equals("Oracle")) {
            return new OracleConnection();
        }
        else if(mType.equals("SQLServer")) {
            return new SqlServerConnection();
        }
        else {
            return null;
        }
    }
}

public class TestConnection {
    public static void main(String[] args) {
        ConnectionFactory factory = new ConnectionFactory("SQLServer");
        Connection conn = factory.createConnection();

        conn = factory.createConnection();
        System.out.println(conn.description());
        /* need to access the getHostType() */
        System.out.println(conn.getHostType());
    }
}