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Message:

mume lele ees suggestion ko

Posted by pankaj on August 21, 2001 at 1:53 AM

> Kishori,
> This is fine for one-time population of a table.
> Suppose I have an applet with a JTable and a textfield.
> Depending on the value of the textfield the table is to be populated.For the first time the solution provided by you will work fine.
> But when I change the value in the text field,how do I clear the rows in the table and populate it with new data assuming that the columncount and type remains the same.

> Pritam

>
> > Yes, the resultset of a query can be populated in a JTable. There are two ways of doing this.
> > 1) You can store all the data from resultset in a two dimensional array of Object and then pass this array to Jtable constructor.
> > Object[]][] data ;;
> > // Populate the data array from resultset
> > String[] columnLabels = { "col1", "col2"... } ;
> > JTable tt = new JTable ( data, columnLabels )

> > 2) You can build your own table model which will be queried by JTable for data in each cell.How to build a table model? Table model will be a class which inherits AbstractTableModel class and will override at least three of its methods viz.
> > public int getColumnCount ( ) ;
> > public int getRowCount ( ) ;
> > public Object getValueAt ( int rowNo, int coulnmNo ) ;
> > If you just override these three methods then your column's header will be given as A, B, C ... . So if you want to supply your own column headers ( certainly you would ) then you need to override another method
> > public String getColumnName ( int col ) ;
> > By methods names you can guess what do you need to write in those methods. However, I will give you hints for every methods. Your table model class will be as follows.
> > class MalaTableModel extends AbstractTableModel {
> > private ResultSet rs ;
> > private ResultSetMetaData rsmd ; // You need to populate it
> > public MalaTableModel ( ResultSet rs ) {
> > this.rs = rs ;
> > // Get the meta data for result set here
> > }
> > public int getRowCount ( ) {
> > // If you are using ODBC2.0 then you can get the
> > // row count from a result set as follows
> > rs.last ( ) ;
> > int rowCount = rs.getRow ( ) ;
> > return rowCount ;
> > // if rs.last ( ) is not supported then
> > /*
> > Keep scrolling from 1st to last row and return the total
> > no of rows
> > */
> > }
> > public int getColumnCount ( ) {
> > return rsmd.getColumnCount ( ) ;
> > }
> > public getValueAt ( int row, int col ) {
> > // Scroll the result set to the row
> > rs.absolute ( row + 1 ) ;
> > return rs.getObject ( col + 1 ) ;
> > }
> > public String getColumnName ( int col ) {
> > return rsmd.getColumnName ( col + 1 ) ;
> > }
> > }

> > //////////////////////////////////////////////////////////////////
> > I haven't used try-catch in above code. But you need to use them
> > ////////////////////////////////////////////////////////////////

> > Before using this table model you need to connect to database and fetch the resultset. Then you can write the following code
> > MalaTableModel mtm = new malaTableModel ( your_result_set ) ;
> > // Don't forget to populate the MetaResultSet object in constructor of
> > // your table model
> > // Create JTable
> > JTable jt = new JTable ( mtm ) ;
> > Now you can add this table jt anywhere you want and your data from resultset will be displayed in this table.
> > Note: Your resultset has to be scrollable in both direction ( forwatrd and backward ) .

> > Thanx
> > Kishori