I'm not quite sure what you mean...
You wan something like that : 
``` java
@Override
protected void populateItem(final LoopItem loopItem) {
                super.populateItem(loopItem);
                if ((getStartIndex() + loopItem.getIndex()) == pageable.getCurrentPage()) {
                    markAsActive(loopItem);
                }
            }
...

protected LoopItem markAsActive(LoopItem loopItem) {
    	loopItem.add(AttributeModifier.append("class", "active"));
    	return loopItem;
    }

```