Populating huge table in SWT/JFace RCP application

Question

How would you go about displaying huge amount of rows in SWT table? Huge is something above 20K rows, 20 columns. Don\'t ask me why I need to show that much data, it\'s not the

Answer 1

SWT can do that for you. When you use the SWT.VIRTUAL style flag, items are only created when scrolled into view. Here's how to do it:

1. Create the table with style SWT.VIRTUAL
2. Set the row count using Table#setItemCount()
3. Add a SWT.SetData Listener that fills the TableItems on demand.

Here's a code snippet:

public static void main( String[] args ) {
    Display display = new Display();
    Shell shell = new Shell( display );
    shell.setLayout( new FillLayout() );
    final Table table = new Table( shell, SWT.VIRTUAL );
    table.setItemCount( 10000 );
    table.addListener( SWT.SetData, new Listener() {
        public void handleEvent( Event event ) {
            TableItem item = (TableItem)event.item;
            item.setText( "Item " + table.indexOf( item ) );
        }
    } );
    shell.setSize( 300, 500 );
    shell.open();
    while( !shell.isDisposed() ) {
        if( !display.readAndDispatch() ) {
            display.sleep();
        }
    }
    display.dispose();
}

Answer 2

1 - use the setText(String[]) instead of setText(int, String) one call instead of several.

2 - use myTable.setRedraw(false) before and myTable.setRedraw(true) after the process to stop all redrawing opérations during loading data.

it's simpler and can improve performance !!

good luck.

on my side using this I load 2500 lines of 20 column in less than 300ms..... on a standard today PC.

Answer 3

You want to do lazy-loading on the table display. Basically, you keep all these objects offscreen in memory, then create only a handful of actual GUI table rows. As the user scrolls you re-render these rows with the objects at that scroll location.

See this article (EDIT: oops I meant this article) for a JFace example.