如何在用户选择后获得原始SelectItem值?

我使用自动建议项目创建输入文本

<af:inputText label="Seller" id="Seller"
              valueChangeListener="#{managedBeanTest.OnChangeSeller}" autoSubmit="true"
              autoComplete="on">
  <af:autoSuggestBehavior suggestedItems="#{managedBeanTest.OnSearchSellers}"/>
</af:inputText>

将SelectItem值设置为我的类Item

public class Test
{
    public static class Item
    {
        public Item(int id, String code, String name) { ... }
        public String toString() { ... }
    }

    public List<SelectItem> OnSearchSellers(String search)
    {
        ResultSet rs;
        ...
        List<SelectItem> result = new ArrayList<SelectItem>();

        while (rs.next())
            result.add(new SelectItem(new Item(rs.getInt(1), rs.getString(2), rs.getString(3))));

        return result;
    }

    public void OnChangeSeller(ValueChangeEvent valueChangeEvent)
    {
        Object newVal = valueChangeEvent.getNewValue();

        if(newVal != null)
          System.out.println("OnChangeSeller: " + newVal.getClass().getName());
    }
}

但在OnChangeSeller中,我只有java.lang.String。 如何获取原始选定项目值(项目类)?