Bug 36672 call hierarchy: Should show a progress bar
The Call Hierarchy view should show a progress bar when searching for callers/callees, allowing the user to abort the search.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/callhierarchy/CallHierarchyContentProvider.java
* @see org.eclipse.jface.viewers.IContentProvider#dispose()
     */
    public void dispose() {}
    /**
     * @see org.eclipse.jface.viewers.ITreeContentProvider#hasChildren(java.lang.Object)
     */
    public boolean hasChildren(Object element) {
        if (element == TreeRoot.EMPTY_ROOT) {
            return false;
        }
        
        if (element instanceof MethodWrapper) {
            MethodWrapper methodWrapper= (MethodWrapper) element;
            if (methodWrapper.getMember().getElementType() != IJavaElement.METHOD) {
                return false;
            }
            if (shouldStopTraversion(methodWrapper)) {
                return false;
            }
        }
        return true;
    }
    /**
     * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
     */
    public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
        this.fViewer = (TreeViewer) viewer;
    }
}