Bug 88577 [Viewers] Deferred viewers in JFace have a dependency on Job
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/deferred/BackgroundContentProvider.java
/**
     * Cleans up this content provider, detaches listeners, frees up memory, etc. 
     * Must be the last public method called on this object.
     */
    public void dispose() {
        cancelSortJob();
        updator.dispose();
        model.removeListener(listener);
    }
    
    /**
     * Force a refresh. Asks the model to re-send its complete contents.
     */
    public void refresh() {
    	if (updator.isDisposed()) {
    		return;
    	}
        model.requestUpdate(listener);
    }
    /**
     * Called from sortJob. Sorts the elements defined by sortStart and sortLength.
     * Schedules a UI update when finished.
     * 
     * @param mon monitor where progress will be reported
     */
    private void doSort(IProgressMonitor mon) {