IllegalStateException error on appending UI element to Form

Question

Hello,

I wrote a simple j2me app for order tracking using Netbeans 6.8. The app allows the user to insert a new order, and search for orders by their order id. The app consists of just a single Midlet and the code is shown below. I have also put up the same code at http://pastie.org/1044069 . Im getting an error "Error:java.lang.IllegalStateException" at line 230 which is searchResultsForm.append(userId);

package hello;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.util.Vector;
import javax.microedition.lcdui.Command;
import javax.microedition.lcdui.CommandListener;
import javax.microedition.lcdui.Displayable;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.StringItem;
import javax.microedition.lcdui.TextField;
import javax.microedition.midlet.*;
import javax.microedition.rms.RecordStore;
import javax.microedition.rms.RecordStoreNotFoundException;


public class J2MEOrderTracker extends MIDlet implements CommandListener {

    private Display display = Display.getDisplay(this);
    Form mainForm = new Form("Order Tracker App");
    Form searchForm;
    StringItem errorMessage = new StringItem("", "");


    //UI Text Fields
    TextField searchField = new TextField("Search By Order Id", null,25,TextField.ANY);
    TextField userId = new TextField("User Id", null,10,TextField.ANY);
    TextField customerId = new TextField("Customer Id", "", 10, TextField.ANY);
    TextField productName = new TextField("Product Name", "", 40, TextField.ANY);
    TextField orderQty = new TextField("Product Qty", "", 2, TextField.NUMERIC);
    TextField orderStatus = new TextField("Order Status", "", 2, TextField.ANY);
    TextField orderId = new TextField("Order Id", "", 25, TextField.ANY);

    //Command buttons
    private Command searchOrderButton = new Command("Search Order", Command.OK,1);
    private Command searchResultsButton = new Command("Search Results",Command.OK, 1);
    private Command insertOrderButton = new Command("Insert New Order",Command.OK, 1);
    private Command addOrderButton = new Command("Add Order", Command.OK, 1);
    private Command exitButton = new Command("Exit Application", Command.OK, 2);
    private Command backButton = new Command("Back",Command.BACK,1);

    //Record Store
    RecordStore recStore;

    //Constants
    private static final String ORDER_SHIPPED = "N";
    private static final String RECORD_ADDED = "N";

    public J2MEOrderTracker(){

        mainForm.addCommand(insertOrderButton);
        mainForm.addCommand(searchOrderButton);
        mainForm.addCommand(exitButton);
        mainForm.append(errorMessage);
        mainForm.setCommandListener(this);
        display.setCurrent(mainForm);

    }

    private void createDatabase(){
        connect();
    }

    private void connect(){
        try {
            try {
                recStore = RecordStore.openRecordStore("OrderDB",false);
            }
            catch(RecordStoreNotFoundException re){

            }
            if (recStore == null) {
                //Create new one
                recStore = RecordStore.openRecordStore("OrderDB", true);
            }


        }
        catch (Exception e){
            System.out.println("Error:"+e);
            errorMessage.setLabel("Error:");
            errorMessage.setText(e.toString());
        }
    }

    private void closeConnection() {
        try{
            if(recStore != null){
                recStore.closeRecordStore();
            }
        }
        catch(Exception e){
            System.out.println("Error:"+e);
            errorMessage.setLabel("Error:");
            errorMessage.setText(e.toString());
        }
    }

    private String insertRecord(){
        String orderId = null;
        try{
                int recordID = 0;
                ByteArrayOutputStream bytstream = new ByteArrayOutputStream();
                DataOutputStream writer = new DataOutputStream(bytstream);

                //Generate a unique key for the Order Id
                long timeStamp = System.currentTimeMillis();
                orderId = userId.getString() + String.valueOf(timeStamp);

                writer.writeUTF(orderId);
                writer.writeUTF(userId.getString());
                writer.writeUTF(customerId.getString());
                writer.writeUTF(productName.getString());
                writer.writeUTF(orderQty.getString());
                writer.writeUTF(ORDER_SHIPPED);
        writer.writeUTF(RECORD_ADDED);
        writer.writeLong(timeStamp);
                writer.flush();

                byte [] rec = bytstream.toByteArray();
                recordID = recStore.addRecord(rec,0,rec.length);
                System.out.println("recordID" + recordID);
        System.out.println("orderId" + orderId);
        writer.close();
        bytstream.close();

        }
        catch(Exception e){
            System.out.println("Error:"+e);
            errorMessage.setLabel("Error:");
            errorMessage.setText(e.toString());
        }
        return orderId;
    }

    private Vector fetchData(String orderId){
        Vector records = new Vector();
        try{
            ByteArrayInputStream stream;
            DataInputStream reader;

            String orderID;

            for(int i = 1 ; i <= recStore.getNumRecords() && records.size() == 0 ; i++){
                byte [] rec = new byte[recStore.getRecordSize(i)];
                rec = recStore.getRecord(i);

                stream = new ByteArrayInputStream(rec);
                reader = new DataInputStream(stream);
                orderID = reader.readUTF();

                if(orderID.equals(orderId)){
                    records.addElement(orderId);
                    // User Id
                    records.addElement(reader.readUTF());
            // Customer Id
            records.addElement(reader.readUTF());
            // Product Name
            records.addElement(reader.readUTF());
            // Productquantity
            records.addElement(reader.readUTF());
            // Order status
            records.addElement(reader.readUTF());
            // sync status
            records.addElement(reader.readUTF());
            // order create date
            records.addElement(reader.readUTF());
            // record id
            records.addElement(new Integer(i));
                }
            }
        }
        catch(Exception e){
            System.out.println("Error:"+e);
            errorMessage.setLabel("Error:");
            errorMessage.setText(e.toString());
        }
        return records;
    }


    public void startApp() {
         createDatabase();
    }

    public void pauseApp() {
    }

    public void destroyApp(boolean unconditional) {
        closeConnection();
    }

    public void commandAction(Command c, Displayable d) {
        try {
            if(c == exitButton){
                destroyApp(false);
                notifyDestroyed();
                return;
            }
            else if(c == backButton){
                display.setCurrent(mainForm);
                mainForm.setCommandListener(this);
                return;
            }
            else if(c == searchOrderButton){
                searchForm = new Form("Search Order By Order Id");
                searchForm.append(searchField);
                searchForm.addCommand(searchResultsButton);
                searchForm.addCommand(backButton);
                searchForm.addCommand(exitButton);
                searchForm.setCommandListener(this);
                display.setCurrent(searchForm);
            }
            else if(c == searchResultsButton){
                Form searchResultsForm = new Form("Search Order Results");

                Vector results = fetchData(searchField.getString());
                if(results != null && results.size() > 0){
                    orderId.setString((String) results.elementAt(0));
            userId.setString((String) results.elementAt(1));
            customerId.setString((String) results.elementAt(2));
                    productName.setString((String) results.elementAt(3));
            orderQty.setString((String) results.elementAt(4));
            orderStatus.setString((String) results.elementAt(5));

                searchResultsForm.append(userId); //Error:java.lang.IllegalStateException
            searchResultsForm.append("\n");
            searchResultsForm.append(customerId);
            searchResultsForm.append("\n");
            searchResultsForm.append(productName);
            searchResultsForm.append("\n");
            searchResultsForm.append(orderQty);
            searchResultsForm.append("\n");
            searchResultsForm.append(orderStatus);
            searchResultsForm.append("\n");
                }
                else{
                    searchResultsForm.append("No Results Found !");
                }
                display.setCurrent(searchResultsForm);
            }
            else if (c == insertOrderButton)
            {
                Form insertOrderForm = new Form("Insert Order");
                insertOrderForm.addCommand(addOrderButton);
                insertOrderForm.addCommand(backButton);
                insertOrderForm.addCommand(exitButton);
                insertOrderForm.append(userId);
                insertOrderForm.append(customerId);
                insertOrderForm.append(productName);
                insertOrderForm.append(orderQty);
                insertOrderForm.setCommandListener(this);
                display.setCurrent(insertOrderForm);
            }
            else if(c == addOrderButton){
                Form orderIdForm = new Form("Order Information");
                String orderId = insertRecord();
                orderIdForm.append("Order successfully inserted.Order Id is "+orderId);
                orderIdForm.addCommand(searchOrderButton);
                orderIdForm.addCommand(exitButton);
                orderIdForm.setCommandListener(this);
                display.setCurrent(orderIdForm);
            }


        }
        catch(Exception e){
            System.out.println("Error:"+e);
            errorMessage.setLabel("Error:");
            errorMessage.setText(e.toString());
        }
    }
}

What could be the problem ? Please help. Thank You.

Answer 1

Stacktrace would really help. Do you get this exception every time? Can you go directly searchResultsForm?

The only possible problem I can guess from your code is that you add your fields to two different forms:

First, to insertOrderForm:

insertOrderForm.append(userId);

than, to searchResultsForm:

searchResultsForm.append(userId);

second attempt throws an exception, which is a part of the Form contract:

If the application attempts to place an item into a Form, and the item is already owned by this or another Form, an IllegalStateException is thrown.