BeanItemContainer & Grid selection, how to use GetItem() with only Object

I’m having a hard time with this and I’m a beginner so please yell at my bad programming practices and tell me if there’s a better way to solve this if possible.

I have a grid. It pulls data from an Access database. (I’m using UCanAccess) I allow the user to filter the entries by Date, then make a selection, and choose to email those entries.

Let’s say I run the program. On the page, I choose a date, the Grid will pull the info from that date. I select a few entries, and click the sendToEmailBtn. Everything works.

Now I choose another date, and the grid is refreshed with a different set of entries. Everything displays properly, it pulled the data correctly.

But this time, when I click sendToEmailBtn, I get a nullpointerexception. I’m guessing because the indexID for the grid is now different from the Index of the BeanItemContainer. (since in the code, to change the grid, I simply used removeAllItems) But I’m not sure what to do here? Is there any other way to do this?I tried to just do this

I wanted to try setting the beanHolder = null and resetting up the grid, etc, but I thought there had to be a better way? Unless there isn’t? I just wanted to know if there’s any other way of using an object to get a bean from BeanItemContainer.

Setting up grid:

BeanContainer<String, Bean> beanHolder = new BeanContainer<String, Bean>(Bean.class);
//Sets up the grid of Beans.
        Grid grid = new Grid (beanHolder);
        grid.setEditorEnabled(true); //Allow changing some parts of the Bean,
                                    //might change later to not allow any changes.
        grid.removeColumn("TID"); //Don't show this column, but it is there.
        grid.setSelectionMode(SelectionMode.MULTI); //Allows to pick multiple entries.

This is my date filter button:

dateButton.addClickListener(new ClickListener() {
            private static final long serialVersionUID = 1L;

            public void buttonClick(ClickEvent event){
                try {
                    Connection conn=DriverManager.getConnection("jdbc:ucanaccess://\\\\server\\folder\\AccessDatabase.mdb");
                     Statement s = conn.createStatement();

                     ResultSet rs = s.executeQuery("SELECT [PLANT]
, [Entry-dt]
, [TID]
 FROM [Query1]
 where [RESOURCE]
 NOT LIKE 'Example*' AND [Entry-dt]
 = #"+new SimpleDateFormat("MM/dd/yyyy").format(df.getValue())+"#");
                     Bean bean = new Bean();

                     while ( {
 + rs.getString(3).split("\\s")[0]
+ rs.getString(3).split("\\s")[0]
                         bean = null;
                         bean = new Bean();
                } catch (ClassNotFoundException | SQLException e) {

And this is where the selection error happens (nullpointerexception)

sendToEmailBtn.addClickListener(new ClickListener() {
            private static final long serialVersionUID = 1L;

            public void buttonClick(ClickEvent event){
A lot of email code
                //Container to hold failed posted Beans
                    BeanContainer<String, Bean> failureBeans = new BeanContainer<String, Bean>(Bean.class);
                    //Email code cut out

                    //Gets which Time entries were selected by User.
                    MultiSelectionModel selection = (MultiSelectionModel) grid.getSelectionModel();
                    selection.getSelectedRows(); ////////////Error happens here
                    //Cycles through each one and emails
                    for (Object itemId: selection.getSelectedRows()){
                        //tests for failed sent entries
                        if (Body.asText().contains("row 1")){
                            pw.write(beanHolder.getItem(itemId).getBean().toString()+ "\r\n");
                    }//End For Loop
                    if (failureBeans.size() >0)
                        UI.getCurrent().addWindow(new BeanErrorWindow(failureBeans));
                }catch(FailingHttpStatusCodeException | IOException e){
            } // Click Event

I changed some of the variable names to try to make the code easier to read.

Just a guess, but it could be that the selection model still has references to the previously selected beans.
When you do beanHolder.removeAllItems(); could you try to do a

grid.setSelectionMode(SelectionMode.NONE); grid.setSelectionMode(SelectionMode.MULTI); This should re-initialize the selection model, if it works then that’s the issue.

It worked, thank you! I never would have thought of that!