Question

I have a recursive method like this:

    protected void executeAction( TreeItem ti )
{
    boolean isChecked = ti.getChecked();

    if ( isChecked )
    {
        Somedata data = (SomeData) ti.getData();
        String action = data.getSelectedAction();
        ActionManager am = data.getActionManager();
        AbstractActionAgent agent = am.getAction( action );
        if ( agent != null )
        {                
            agent.updateModel( data );   //Makes a server trips and long computation               
        }
    }
    int itemcnt = ti.getItemCount();
    TreeItem[] childTrees = ti.getItems();

    for ( int i = 0; i < itemcnt; i++ )
    {
        executeAction( childTrees[i] );
    }
}

My updateModel method freezes the UI, so I tried using Job, but my problem is that I want the update model to be executed for checked TreeItem only and it should follow the sequence of checked TreeItems. If I use Job, I have no control over which checked TreeIem is processed first. Also I tried putting the whole executeAction method in a Job, but ran into invalid thread while accessing the TreeItem.

I need some ideas so that I can spwan a new thread while maintaining the sequence and not freezing my UI.

Thanks.

Answer 1

You could try this. Collect you model objects in a Tree and run that updateModel in a separate job. The below code doesn’t run. You may need to tweak it a bit.

  class Node {
    private SomeData nodeData;
    private List<Node> children = new ArrayList();

// Create getters, setters..
}

protected void executeAction( TreeItem ti, Node parentNode ) {
boolean isChecked = ti.getChecked();
Node n = null;
if ( isChecked )
{
    Somedata data = (SomeData) ti.getData();
    if (parentNode != null) {
       n = new Node();
       n.setNodeData(data);
       parentNode.addChild(n);
    }

}
int itemcnt = ti.getItemCount();
TreeItem[] childTrees = ti.getItems();

for ( int i = 0; i < itemcnt; i++ )
{
    executeAction( childTrees[i],n );
}

}