// Get value for a specific row and column combination.
public Object getValueAt(int row, int col) {
Download download = downloadList.get(row);
switch (col) {
case 0: // URL
return download.getUrl();
case 1: // Size
int size = download.getSize();
return (size == -1) ? "" : Integer.toString(size);
case 2: // Progress
return new Float(download.getProgress());
case 3: // Status
return Download.STATUSES[download.getStatus()];
}
return "";
}
/* Update is called when a Download notifies its
observers of any changes */
public void update(Observable o, Object arg) {
int index = downloadList.indexOf(o);
// Fire table row update notification to table.
fireTableRowsUpdated(index, index);
}
}
The DownloadsTableModel class essentially is a utility class utilized by the "Downloads"
JTable instance for managing data in the table. When the JTable instance is initialized, it is
passed a DownloadsTableModel instance. The JTable then proceeds to call several methods
on the DownloadsTableModel instance to populate itself. The getColumnCount( ) method
is called to retrieve the number of columns in the table. Similarly, getRowCount( ) is used to
retrieve the number of rows in the table. The getColumnName( ) method returns a column's
name given its ID. The getDownload( ) method takes a row ID and returns the associated
Download object from the list. The rest of the DownloadsTableModel class' methods, which
are more involved, are detailed in the following sections.
The addDownload( ) Method
The addDownload( ) method, shown here, adds a new Download object to the list of
managed downloads and consequently a row to the table:
// Add a new download to the table.
public void addDownload(Download download) {
// Register to be notified when the download changes.
download.addObserver(this);
downloadList.add(download);
// Fire table row insertion notification to table.
fireTableRowsInserted(getRowCount() - 1, getRowCount() - 1);
}
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