CODEWITHSUNDEEP
javaswingjtable
3kings
3kings

Reputation: 838

JTable returning JTable when calling getModel()

My JTable is declared as so:

String[] cols = {"Name","Location"};
String[][] data = new String[][] {{"Name","Location"}};
JTable table = new JTable(data, cols);

So i came across a problem when trying to update my JTable's data... I'm suppose to be adding a new row to the table. Here is my code for that:

data = new String[][] {{"Name","Location"}{"Name1","Location1"}};
DefaultTableModel dm = (DefaultTableModel)(table.getModel());
dm.fireTableDataChanged();

For some reason i get an error on the Line:

DefaultTableModel dm = (DefaultTableModel)(table.getModel());

The error shown is...

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: javax.swing.JTable$1 cannot be cast to javax.swing.table.DefaultTableModel
at client.pages.ClientPage.update(ClientPage.java:171)

Line 171 of my ClientPage.java is the above line of code that i said the error is on.

Anyone know why its doing this? 

table.getModel(); //Suppose to return TabelModel not JTable

Upvotes: 0

Views: 7616

Answers (2)

FThompson
FThompson

Reputation: 28707

table.getModel() isn't returning a JTable, it's returning an anonymous class in JTable that extends TableModel. Therefore, table.getModel() is indeed returning the correct class type.

The error occurs, however, because you try to cast this anonymous table model to DefaultTableModel, which is another subclass of TableModel, but is not the type being returned by table.getModel().

To fix this, simply treat the table model as the interface type TableModel; don't assume it's a DefaultTableModel.

Upvotes: 4

MadProgrammer
MadProgrammer

Reputation: 347334

Start by taking a look at How to Use Tables and the JavaDocs for DefaultTabelModel

You should change the way you are creating the table and model to something more like...

String[] cols = {"Name","Location"};
String[][] data = new String[][] {{"Name","Location"}};
JTable table = new JTable(new DefaultTableModel(date, cols));

JTable(Object[][], Object[]) actually uses it's own implementation of a the TableModel

Next, change....

data = new String[][] {{"Name","Location"}{"Name1","Location1"}};
DefaultTableModel dm = (DefaultTableModel)(table.getModel());
dm.fireTableDataChanged();

to something more like...

data = new String[][] {{"Name","Location"}{"Name1","Location1"}};
DefaultTableModel dm = (DefaultTableModel)(table.getModel());
dm.fireTableDataChanged();

to something more like...

data = new String[] {"Name1","Location1"};
DefaultTableModel dm = (DefaultTableModel)(table.getModel());
dm.addRow(data);

Upvotes: 3

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