Question

Hey guys I am doing a Database Manager proyect and I am not able to display all the data that I get from a db on a JTable. The code is the following:

private Collection<Map<String, String>> allData;
private void refresh()
{
    while(tableModel.getRowCount() > 0)
    {
        tableModel.removeRow(0);
    }
    try
    {
allData = manager.get((String) DatabaseJList.getInstance().getSelectedObject()).getDataManager().getAllFieldsValues();
//This works fine, I have prove to print allData value and it is correct
Object[] rowToAdd = new Object[manager.get((String) DatabaseJList.getInstance().getSelectedObject()).getDataManager().getColumnNumber()];
//I create a Object[] with the number of colums size,works fine too
ArrayList<String> rowx = new ArrayList<String>();

for (Map<String, String> rowz: allData)
            {
                rowx = (ArrayList<String>) rowz.values();
                int i = 0;
                for (String str : rowx)
                {
                    rowToAdd[i] = str;
                }
            }
            tableModel.addRow(rowToAdd);
        }

My idea is to use the method refresh at the beginning to load all the table data, and to call it again after insert,delete,modify to refresh the data but I get this error here:

java.uti.HashMap$Values cannot be cast to java.util.ArrayList

As I know the method .values() returns a Collection so don’t know where is the problem here.

Thanks a lot for the help guys.

Answer 1

Why does rowx need to be of type ArrayList<String>? Can’t you just declare it as Collection<String>?