Allows to select elements via checkboxes or radiobuttons. The selection is evaluated when validate() is called.

Usage pattern

    class MyComponent extends ComponentSupport {

      selectionMgr = new SelectionMgr();

      public Document render(RequestContext context) throws Exception {
        Document document = XmlUtils.createDocument();
        selectionMgr.startRendering(context);
        for (int nodeIndex = 0; nodeIndex < nodeCount; nodeIndex++) {
          Object node = ...
          Element elem = renderElement(node);
          selectionMgr.renderButton(element, node);
        }
        selectionMgr.stopRendering();
        return document;
      }

      public boolean validate(RequestContext context) {
        selectionMgr.validate(context);
        ...
      }

    }