如何在ajax方法中获取单击的项目？

Suppose the code of this page:

假设这个页面的代码：

<h:form prependId="false" id="form">

    <h:selectManyCheckbox id="checkBoxList" value="#{backedBean.lstIdSelectedItems}" layout="pageDirection">
        <f:selectItems value="#{backedBean.lstAvailableItems}" var="item" itemLabel="#{item.label}" itemValue="#{item.value}" />
        <f:ajax listener="#{backedBean.itemClicked}" />
    </h:selectManyCheckbox>

</h:form>
<