My Original Thread of Dyanamic Array

Question

Hello Everyone,
I can't give any size to the array because this array will be increased during run time.The entries are entered by the User into the form(or frame) will be inserted into the database. Then, all the records will be fetched from the database and shown in the JTable. So, I can't know the number of entries of the user but I know the columns of the JTable which are same as that of the database's. That's why, I am using Dynamic Array.
I referred another Constructor of JTable that accepts only Vector object argument that is,
JTable table = new JTable(Vector data, Vector columns);
then, I tried the following codings:
try
stmt=con.createStatement();
rs=stmt.executeQuery("SELECT * FROM Report");
Vector data = new Vector();
Vector colheads = new Vector();
while(rs.next())
data.addElement(rs.getString("Enter_Year"));
data.addElement(rs.getString("UG_Production_Mi_Te"));
data.addElement(rs.getString("OC_Production_Mi_Te"));
data.addElement(rs.getString("Total_Production_Mi_Te"));
data.addElement(rs.getString("OBR_MM3"));
data.addElement(rs.getString("OMS_Te"));
data.addElement(rs.getString("Coal_Offtake_Mi_Te"));
data.addElement(rs.getString("Supply_to_Steel_Plant_Th_Te"));
data.addElement(rs.getString("Royalty_SalesTax_MP_Crs"));
data.addElement(rs.getString("Royalty_SalesTax_CG_Crs"));
data.addElement(rs.getString("Total_ManPower"));
data.addElement(rs.getString("Fatality_Rate_per_Mi_Te_Output"));
data.addElement(rs.getString("Total_Wellfare_Expenditure_Crs"));
colheads.addElement("Year");
colheads.addElement("U.G.Production(in Mi.Te.)");
---------My all column names----------
JTable table = new JTable(data,colheads); // ClassCastExecption error
JScrollPane jsp = new JScrollPane(table);
add(jsp);
this.setVisible(true);
catch(Exception e)
System.out.println(e);
Then, I got an error in the statement containing comment line, ClassCastExecption . I cast the Vector object inside the JTable Constructor like,
JTable table = new JTable((String) data, colheads);
but, it gave an error related to JTable Constructor. Then, I cast it above the JTable object and then pass the String array object into the JTable Constructor but JTable accepts only Vector and 2D String array object for both of its argument. It is not accepting the One Dimensional String array object for data or info. it shows and one Vector object for column headings. How can I Cast the Vector object into the String object and pass the Vector objects into the Constuctor of JTable?
I am trying to cast the Vector object into String object because at the comment line Statement, I received an error " java.lang.ClassCastExecption"
and please tell me another thing that how can I iterate through the array records when the array is initialized during declaration like,
while(rs.next())
String [][] data = {{rs.getString("Enter_Year"),rs.getString("UG_Production_Mi_Te")}};
String colheads[] = {"Year", ---------};
table = new JTable(data,colheads);
jsp = new JScrollPane(table);
This coding is running and reading all the record from the database but it is showing only last record of database into the JTable and overlapps all the previous records. So, I am trying to iterate through the Array and I want to show one record at one time and then increment the index of Array by 1 and then show the next record into the JTable without overlapping.

Answer 1

jschell wrote:
M.V.Asolkar wrote:
This coding is running and reading all the record from the database but it is showing only last record of database into the JTable and overlapps all the previous records. So, I am trying to iterate through the Array and I want to show one record at one time and then increment the index of Array by 1 and then show the next record into the JTable without overlapping.This is just as confused as your last question. Right now your code is so jumbled that there really isn't any easy way to correct it.
You need to stop attempting to mix GUI and JDBC. Your code should have two classes.
1. Class that does jdbc and NO gui.
2. Class that does gui, it uses class 1.
You start by creating 2 or at least part of 2 so you can figure out the exact data structure that you need to populate your gui.
AFTER you do that then you write 1 such that it creates and returns the data structures that you discovered.jschell is absolutely on point, Asolkar, I feel like you are just putting some hacked code together... best practice would be create a seperate class that serve for jdbc and query construction. Then you you can use different class to do any kind of format or representation.
In this case generate a class class, like example:
DBConnect.java
*@author Anuradha Uduwage
public class DBConnect {
        static String url = "jdbc:oracle:thin:@tnsproperties";
        // shared datbase connection object
        private Connection conn;
        // shared statement object. 
        private Statement stmt;
        private Statement substmt;
         * connects to the oracle instance.  Also opens the statement object we use to communicate.
         * @return true if successful, false if an exception occurs
        public boolean init(){
                try {
                        // NOTE: If you want to use a different database this DriverManager statement needs to be replaced
                        //       with the appropriate driver.
                DriverManager.registerDriver (new oracle.jdbc.driver.OracleDriver());
                        conn = DriverManager.getConnection
                        stmt = conn.createStatement();
                        substmt = conn.createStatement();
                        return true;
                } catch (SQLException e) {
                        e.printStackTrace();
        // if we had an exception allow the system to close down gracefuly.            
                return false;
        //this is the method to generate ur query
        public Vector<Vector<String>> foo() {
                Vector<Vector<String>> fooVector = new Vector<Vector<String>>();
                try {
                        ResultSet rs = stmt.executeQuery("select column1, .. columnN from whatever");
                        while (rs.next()) {
                                Vector<String> boo = new Vector<String>();
                                boo.add(rs.getString("ColumnName"));
                                boo.add(rs.getString("ColumnName"));
                                fooVector.add(boo);
                } catch (SQLException e) {
                        e.printStackTrace();
                return fooVector;
}and then you can create a another class to generate your JTable or what ever you want.
And Geeze, if you want an answer please try to put sometime on writing the post, and be more clear...
Anuradha Uduwage
Edited by: Tilter on May 15, 2009 9:14 PM
Edited by: Tilter on May 15, 2009 9:15 PM