Please help with my helper class

Question

Hi,
plz I need some assistance with this:
I have a big table which consist of 200 columns. This table gets fields from different tables. It has records of orders which may have several items and each item can have up to 8 taxes. So i have fields reaping for other order order records. I need to display an order then have a navigation to list items in details, with all its taxes, one by one.
Here is how I have decided to do it in a nutshell. I have decided to get all taxes of a particular item and put in a map with tax_codes as values and tax details arraylist as values. I then add this to an item with its other details. then I add items to a particular order. I have separated orders,items and taxes in their separate beans. Im trying to first the implimentation for each order, item and taxes by displaying them on a JSP. However am currently getting the following error with taxdetails:
java.lang.ClassCastException: OrderItems.ItemTax cannot be cast to java.lang.String
at OrderItems.OrderDetails.getItemTaxDetails(OrderDetails.java:166)
at OrderItems.Controller.processRequest(Controller.java:57)
at OrderItems.Controller.doGet(Controller.java:72)
I have a list of all itemTaxCodes am iterating and am casting to string...am not casting ItemTax object.Here is my code below:
OrderDetails.java
package orderitems;
import java.sql.*;
import java.util.*;
public class OrderDetails {
    private LineOder lineOrder;
    private Map lineItems;
    //returns an item number, key_item, from its unique keys
    public int getItemNumber(int key_item, String key_year,
            String key_office,String key_client,String key_company){
        Connection conn = null;
        Statement stat = null;
        ResultSet rst = null;
        int itmNum = 0;
         * key_item a unique number for an item.
         * key_year,key_office,key_client,key_company unique keys
         * for each order where this key_item is taken
         * from.
        String select = "SELECT key_item FROM "+
                Constants.WEB_TABLE +" WHERE key_item = " + key_item +
                " AND key_year = '" + key_year + "'" +
                " AND key_office = '" + key_office + "'" +
                " AND key_client = '" + key_client + "'" +
                " AND key_company = '" + key_company +"'";
        DbConnection dbConn = new DbConnection();
        try {
            conn = dbConn.getDbConnection(Constants.WEB_JNDI);
            stat = conn.createStatement();
            rst = stat.executeQuery(select);
            if(rst.next()){
                itmNum = Integer.parseInt(rst.getString("key_item"));
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally{
            SQLHelper.cleanUp(rst, stat, conn);
        return itmNum;
    //get a list of item number(item codes)
    public List getAllItemNumbers(String key_year,
            String key_office,String key_client,String key_company){
        List itemNumbers = new ArrayList();
        LineItem itemNumber = null;
        Connection conn = null;
        Statement stat = null;
        ResultSet rst = null;
        String select = "SELECT key_item FROM "+ Constants.WEB_TABLE +
                " WHERE key_year = '" + key_year + "'" +
                " AND key_office = '" + key_office + "'" +
                " AND key_client = '" + key_client + "'" +
                " AND key_company = '" + key_company + "'";
        DbConnection dbConn = new DbConnection();
        try {
            conn = dbConn.getDbConnection(Constants.WEB_JNDI);
            stat = conn.createStatement();
            rst = stat.executeQuery(select);
            while(rst.next()){
                itemNumber = new LineItem();
                itemNumber.setKey_item(Integer.parseInt(rst.getString("key_item")));
                itemNumbers.add(itemNumber);
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally{
            SQLHelper.cleanUp(rst, stat, conn);
        return itemNumbers;
    //get a list of tax codes
    public List getAllTaxCodes(int key_item, String key_year,
            String key_office,String key_client,String key_company){
        Connection conn = null;
        Statement stat = null;
        ResultSet rst = null;
        ItemTax taxCode;
        List taxCodes = new ArrayList();
        int itemNum = getItemNumber(key_item, key_year,
                key_office,key_client,key_company);
        String select = "SELECT key_tax_code FROM "+
                Constants.WEB_TABLE +" WHERE key_item = " + itemNum +
                " AND key_year = '" + key_year + "'" +
                " AND key_office = '" + key_office + "'" +
                " AND key_client = '" + key_client + "'" +
                " AND key_company = '" + key_company +"'";
        DbConnection dbConn = new DbConnection();
        try {
            conn = dbConn.getDbConnection(Constants.WEB_JNDI);
            stat = conn.createStatement();
            rst = stat.executeQuery(select);
            while(rst.next()){
                taxCode = new ItemTax();
                taxCode.setKey_tax_code(rst.getString("key_tax_code"));
                taxCodes.add(taxCode);
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally{
            SQLHelper.cleanUp(rst, stat, conn);
        return taxCodes;
    //use tax code to get tax details
    public Map getItemTaxDetails(String key_year,String key_office,
            String key_client,String key_company,int key_item){
        ItemTax taxDetail = null;
        List taxDetails = new ArrayList();
        List itemTaxCodes = new ArrayList();
        Map itemTaxdetails = new HashMap();
        Connection conn = null;
        Statement stat = null;
        ResultSet rst = null;
        //get a list of all tax codes of an item with a
        //given item number
        itemTaxCodes = getAllTaxCodes(key_item,key_year,///a list of tax codes
                key_office,key_client,key_company);
        DbConnection dbConn = new DbConnection();
        try {
            conn = dbConn.getDbConnection(Constants.WEB_JNDI);
            stat = conn.createStatement();
            for(Iterator taxCodeIter= itemTaxCodes.iterator(); taxCodeIter.hasNext();){
                String taxCode = (String)taxCodeIter.next();/////casting taxtCode to string***exception occurs from here
                String select = "SELECT tax_type,tax_value," +
                        "tax_limit_val FROM "+ Constants.WEB_TABLE +
                        " WHERE key_item = "+ key_item +
                        " AND key_year = '" + key_year + "'" +
                        " AND key_office = '" + key_office + "'" +
                        " AND key_client = '" + key_client + "'" +
                        " AND key_company = '" + key_company +"'" +
                        " AND key_tax_code = '" + taxCode + "'";///tax code string
                rst = stat.executeQuery(select);
                while(rst.next()){
                    taxDetail = new ItemTax();
                    //records to be displayed only
                    taxDetail.setKey_item(Integer.parseInt(rst.getString("key_item")));
                    taxDetail.setTax_value(rst.getString("tax_value"));
                    taxDetail.setTax_limit_val(Float.parseFloat(rst.getString("tax_limit_val")));
                    //////other details records ommited//////////////////////////
                    taxDetails.add(taxDetail);
            //a HashMap of all tax code as keys and list of details as values 4 each key
            for(int i = 0;i<itemTaxCodes.size(); i++){
                itemTaxdetails.put(itemTaxCodes.get(i),taxDetails.get(i));
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally{
            SQLHelper.cleanUp(rst, stat, conn);
        return itemTaxdetails;
    //details of an item with all its taxes
    public List getAllItemDetails(String key_year,
            String key_office,String key_client,String key_company){
        List lineItems = new ArrayList();
        List itemNumbers = new ArrayList();
        Map taxDetails = new HashMap();
        LineItem item = null;
        Connection conn = null;
        Statement stat = null;
        ResultSet rst = null;
        //A list of all item numbers in the declaration
        itemNumbers = getAllItemNumbers(key_year,
                key_office,key_client,key_company);
        DbConnection dbConn = new DbConnection();
        try {
            conn = dbConn.getDbConnection(Constants.WEB_JNDI);
            stat = conn.createStatement();
            for(Iterator itemIter= itemNumbers.iterator(); itemIter.hasNext();){
                int itemNumber = ((Integer)itemIter.next()).intValue();
                String select = "SELECT item_description,item_mass," +
                        "item_cost" +
                        " FROM " + Constants.WEB_TABLE +
                        " WHERE key_year = '"+key_year+"'" +
                        " AND key_office = '"+key_office+ "'"+
                        " AND key_client = '"+key_client+ "'"+
                        " AND key_company = '"+key_company+ "'"+
                        " AND key_item = " + itemNumber;
                rst = stat.executeQuery(select);
                while(rst.next()){
                    item = new LineItem();
                    item.setItem_description(rst.getString("item_description"));
                    item.setItem_mass(Float.parseFloat(rst.getString("item_mass")));
                    item.setKey_item(Integer.parseInt(rst.getString("item_cost")));
                    //////other details records ommited//////////////////////////
                    //A HashMap of all itemTaxeCodes as its keys and an ArrayList of itemTaxedetails as its values
                    taxDetails = getItemTaxDetails(item.getKey_year(),item.getKey_office(),
                            item.getKey_client(),item.getKey_company(),item.getKey_item());
                    //item tax details
                    item.setItmTaxes(taxDetails);
                    //list of items with tax details
                    lineItems.add(item);
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally{
            SQLHelper.cleanUp(rst, stat, conn);
        return lineItems;
    public Set getDeclarations(String key_year,String key_cuo,
            String key_dec,String key_nber){
        List lineItems = new ArrayList();
        Set lineOrders = new HashSet();
        Connection conn = null;
        Statement stat = null;
        ResultSet rst = null;
        LineOder lineOrder = null;
        String select = "SELECT * FROM " + Constants.WEB_TABLE +
                " WHERE key_year = '" + key_year + "'" +
                " AND key_cuo = '" + key_cuo + "'" +
                " AND key_dec = '" + key_dec + "'" +
                " AND key_nber = '" + key_nber + "'";
        DbConnection dbConn = new DbConnection();
        try {
            conn = dbConn.getDbConnection(Constants.WEB_JNDI);
            stat = conn.createStatement();
            rst = stat.executeQuery(select);
            while(rst.next()){
                lineOrder = new LineOder();
                lineOrder.setKey_year(rst.getString("key_year"));
                lineOrder.setKey_office(rst.getString("key_cuo"));
                lineOrder.setKey_client(rst.getString("key_dec"));
                lineOrder.setKey_company(rst.getString("key_nber"));
                ////list of items with all their details
                lineItems = getAllItemDetails(lineOrder.getKey_year(),lineOrder.getKey_office(),
                        lineOrder.getKey_client(),lineOrder.getKey_company());
                //setting item details
                lineOrder.setItems(lineItems);
                //a list of order with all details
                lineOrders.add(lineOrder);
        } catch (SQLException ex) {
            ex.printStackTrace();
        } finally{
            SQLHelper.cleanUp(rst, stat, conn);
        return lineOrders;
} and my testing servlet controller
Controller.java
package orderitems;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class Controller extends HttpServlet {
    private Map taxDetails = new HashMap();
    //private List itemDetails = new ArrayList();
    //private Set orderDetails = new HashSet();
    private OrderDetails orderDetails = null;
    protected void processRequest(HttpServletRequest request,
            HttpServletResponse response)throws
            ServletException, IOException {
        response.setContentType("text/html;charset=UTF-8");
        String key_year = "2007";
        String key_office = "VZX00";
        String key_company = "DG20";
        String key_client =  "ZI001";
        int key_item = 1;
        String nextView = "/taxdetails_list.jsp";
        //String nextView = "/order_list.jsp";
        //String nextView = "/items_list.jsp";
        orderDetails = new OrderDetails();
        taxDetails = orderDetails.getItemTaxDetails(key_year,key_office,
                key_company,key_client,key_item);
        //Store the collection objects into HTTP Request
        request.setAttribute("taxDetails", taxDetails);
        RequestDispatcher reqstDisp =
                getServletContext().getRequestDispatcher(nextView);
        reqstDisp.forward(request,response);
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response)throws
            ServletException, IOException {
        processRequest(request, response);
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response)throws
            ServletException, IOException {
        processRequest(request, response);
}I have not included code for beans to reduce on bulk.please help and with suggestions...
Thanx in advance.
Edited by: aiEx on Oct 3, 2007 8:13 AM

Answer 1

aiEx wrote:
sometimes a tap on the head is needed to really learn and understand :-)You're casting them to the String type while they are of the ItemTax type and you've confirmed it yourself. Likely you misunderstood the concepts behind "casting" and you was expecting some magic that they are automatically converted somehow from the ItemTax type to the String type while the ItemTax class isn't a subclass of the String class :)