Random data from db

Question

Hi all,
im doing a java project on my school Object Orientated Analysis and Design module. i'm doing a disc rental system, and was trap in one of my class file.
i have 3 files here,
1. ChooseDiscForm.java
the GUI class, which contain all my buttons, table, labels etc.
2. ChooseDiscController.java
this file is link to my ChooseDiscForm, where it store the method of
what should my buttons should do when i click on it. The method here link my button to my database (db) connection file called Disc.java,
3. Disc.java
stores all the dbQuery and connection to my db.
Inside my db, which contains all my discs record, like movie title, decription of movie bla bla, and EACH disc has a unique discId.
i need to do a random generating code for my button inside ChooseDiscForm.java, where it will call a method named ''processToRandomSearch()' inside my ChooseDiscController, and from thise processToRandomSearch(), it will call another method named ''ArrayList<Disc> dataList = d.getRandomDisc(id)'' which is stored inside Disc.java.
i have found the java random number coding. but i dunno how do i put inside my disc.java.
in my disc.java, where i will retrieve my disc info out of my db, my lecture suggested me to create a arraylist, to store my all discId(from db), and put it inside he random number code. but i tried it many times. it cant work.. ;'(. here is my code:
ChooseDiscForm.javau
//delare object link to RentDiscController.java
ChooseDiscController getControl = new ChooseDiscController();
//action for my button.
private void submitSearchByRandom(ActionEvent e){  
                     //inside ChooseDiscController.java file                                    getControl.processToRandomSearch();
                     //my table to put the data into.
     jScrollPane.setViewportView(getJTable1());
//my table
private JTable getJTable1() {
     if (jTable1 == null) {
     String[] columnNames = {"Disc Title",
                   "Disc ID",
                   "Status",
                   "Type",
                   "Description",
                                   "Language",
                   "Rating",
                   "No. of Disc",
                   "Cost Price",
     jTable1 = new JTable(data1, columnNames);
                     jTable1.setBounds(new Rectangle(13, 22, 483, 224));
        return jTable1;
ChooseDiscController.java
//create object link to Disc.java entity
Disc d = new Disc();
static ArrayList<Disc> getDiscArray = new ArrayList<Disc>();
static Object[][] data = new Object[13][13];
//method from my button
public void processToRandomSearch(){
                      // this method is in my disc.java file.
      ArrayList<Disc> dataList = d.getRandomDisc(id);
                      //this print my data into the table.
         getDiscArray = dataList;
    public Object[][] getData(){
         for(int i=0; i<getDiscArray.size();i++){
              data[0] = getDiscArray.get(i).gettitle();
          data[i][1] = getDiscArray.get(i).getdiscId();
          data[i][2] = getDiscArray.get(i).getstatus();
          data[i][3] = getDiscArray.get(i).gettype();
          data[i][4] = getDiscArray.get(i).getdesc();
          data[i][5] = getDiscArray.get(i).getlanguage();
          data[i][6] = getDiscArray.get(i).getrating();
          data[i][7] = getDiscArray.get(i).getnoOfDisc();
          data[i][8] = getDiscArray.get(i).getcostPrice();
     return data;
disc.java
//Search by random db connection
public ArrayList<Disc> getRandomDisc(String id){
ArrayList<Disc> discList = new ArrayList<Disc>();
/*this funtion is what i found on net. not sure is this the right place to put in.*/          
Random r = new Random();
// Code to access db
ResultSet rs = null;
String dbQuery = "SELECT * FROM Disc where discId \'" + id + "\'";
DBController db = new DBController();
System.out.println(dbQuery);
db.setUp("IT2292");
rs = db.Request(dbQuery);
try{
/*i have to make it a while loop, so that my data printed on my table will not overlap one another. but print all my disc out.*/
while (rs.next()){
/*my lecture wanted me to cast my discId into an array, its a cheating way to declear the new String[20],  i dunno what is the right way to get the size from my db, and my disc records inside db contain 20 disc with a few with the same name like Transformers. but they are unqiuely identify by their discId like 'ECM0001' etc.*/
/*this chunk of codes here, i need to randomly generate 10 records from my db which includes all the disc info and display it into my table.     */                    
         String[] y = new String[20];
         y[i] = rs.getString("discId");
        int w = Integer.parseInt(y); // this line.
/*error here. as i compile, it's able to find the discId, but somehow, the console say there is a error here they din tell me why. pls help me. thanks /*
w = r.nextInt(10);     
     String a = rs.getString("title");
     String c = rs.getString("status");
     String e = rs.getString("type");
     String f = rs.getString("desc");
     String g = rs.getString("language");
     String h = rs.getString("rating");
     String k = rs.getString("costPrice");
discList.add (new Disc(a,b,c,e,f,g,h,j,k));
     catch (Exception e) {
     e.printStackTrace();
     db.terminate();
     return discList;
thats all. sorry for the long winded story.. i have burned many night of mid-night oil trying to get this done.. im only 3 days to my presentation day.. and i need to hand it up as soon as possible for my team lead to compile them. pls help me java experts!! thanks:)
Message was edited by:
Titus-tan

Answer 1

Hi pal,
the item i retrieved out from my db is String, so i have to pass it into a string. and from the example of the random, it is called as int w = r.nextInt();, and i have to pass my string into this random coding. shouldnt i pass my string into integer?
Titus