Using DAO,DTO pattern as MVC

Question

    public abstract class BaseDAO<T extends BaseDTO> {

        public Integer create(T dto) {

        }
        public Integer update(T dto) {

        }
        public Integer delete(T dto) {

       }

     }


    public class JobDAO extends BaseDAO<JobDTO> {

        public JobDAO(Connection conn) {
            super(conn);
        }

        @Override
        public String getDBTableName() {
            return "JobTABLE";
        }
    }


    public class BaseDTO {

        protected Integer ID;

        public Integer getID() {
            return ID;
        }

        public void setID(Integer ID) {
            this.ID = ID;
        }
    }


    public class JobDTO extends BaseDTO {

        Integer employerID;
        //getter
        //setter

     }



   public class Job_GUI extends javax.swing.JFrame {
    //GUI properties
    }

I am trying to understandModel, View, Controller Convention and I want to applyMVC to above class structures I have which consist of Data Transfer and Access Objects. What I'm failing to understand, is my structure above MVC? if so, what is the model? I'm guessing the DTO are themselves Model. Job_GUI is a View which I know already, but what is the Controller??

I want to directly write the actionPerformed codes in the Job_GUI itself, something like this snippet to create a job in db:

JobDAO jdao = new JobDAO(conn);
           //create object jobDTO to hold all form values to be passed to JobDAO
           final JobDTO jobDTO = new JobDTO();
           //populating JobDTO with values from form
           jobDTO.setEmployerID(id);
           jobDTO.setDescription(description.getText());
           jobDTO.setTitle(txtTitle.getText());
           jdao.create(jobDTO);

but should the above be in the Job_GUI class itself or somewhere else. If I were to insert the above snippet in Job_GUI am I moving away from the MVC convention as such? Where would you put the above snippet? The confusion lies in identifying which is the controller class out of all that I have if I were to use the DTO,DAO Design Pattern for database interaction.

Answer 1

       JobDAO jdao = new JobDAO(conn);
       //create object jobDTO to hold all form values to be passed to JobDAO
       final JobDTO jobDTO = new JobDTO();
       //populating JobDTO with values from form
       jobDTO.setEmployerID(id);
       jobDTO.setDescription(description.getText());
       jobDTO.setTitle(txtTitle.getText());
       jdao.create(jobDTO);

In above code you basically doing job of Controller because you assigning values to your DTO and then calling create method of your DAO. This is what Controller is supposed to do. So you are right on this part except one small correction :

    JobDAO jdao = new JobDAO(conn);  //not preferable
    JobDAO jdao = new JobDAO();  //preferred inside Controller class

Will suggest you to keep connection specific code inside your DAO. Your Controller class shouldn't know about your DB connection. You can perform this inside your create/update/delete methods of DAO.

DAO where you actually interact with DB is part of MODEL in MVC.

Just keep in mind few things :

• MVC (architectural design pattern) stresses on separation of concern. So make sure that you have well defined classes for View, Controller and Model
• Your class names should convey which component it belongs to (BaseDAO etc)
• Controller controls View and Model. So your View and Model should not be aware of each other.

And as you mentioned that you are already clear with View. So i haven't put any explanation on that.