RichFaces fileupload清晰明了

Question

组件rich:fileUpload支持onclear事件，但我无法区分CLEAR事件和CLEARALL事件。代码：

<rich:fileUpload fileUploadListener="#{WF_Attachment_BB.uploadListener}"
    maxFilesQuantity="#{WF_Attachment_BB.availableQuantity}"
    autoclear="false"
    clearControlLabel="clear"
    clearAllControlLabel="clearAll"
    onclear="clearFunc()"
    id="upload" >
</rich:fileUpload>
<a4j:jsFunction id="clearFunc" name="clearFunc" ajaxSingle="true"
    actionListener="#{WF_Attachment_BB.clearUploadData}">
    <a4j:actionparam name="fName"/>
</a4j:jsFunction>

我想这样做：当我点击clearControlLabel时，WF_Attachment_BB.clearUploadData会从服务器清除一个，当我点击clearAllControlLabel时，WF_Attachment_BB.clearUploadData会从服务器清除所有内容。 / p>