JSF 2 -- Composite component with optional listener attribute on f:ajax
I have a composite component that looks something like this:
<!DOCTYPE html>
<html
xmlns:h="http://java.sun.com/jsf/html"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:dm="http://davemaple.com/dm-taglib"
xmlns:rich="http://richfaces.org/rich"
xmlns:cc="http://java.sun.com/jsf/composite"
xmlns:fn="http://java.sun.com/jsp/jstl/functions"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:a4j="http://richfaces.org/a4j">
<cc:interface>
<cc:attribute name="styleClass" />
<cc:attribute name="textBoxStyleClass" />
<cc:attribute name="inputTextId" />
<cc:attribute name="labelText" />
<cc:attribute name="tabindex" />
<cc:attribute name="required" default="false" />
<cc:attribute name="requiredMessage" />
<cc:attribute name="validatorId" />
<cc:attribute name="converterId" />
<cc:attribute name="title"/>
<cc:attribute name="style"/>
<cc:attribute name="unicodeSupport" default="false"/>
<cc:attribute name="tooltip" default="false"/>
<cc:attribute name="tooltipText" default=""/>
<cc:attribute name="tooltipText" default=""/>
<cc:attribute name="onfail" default=""/>
<cc:attribute name="onpass" default=""/>
</cc:interface>
<cc:implementation>
<ui:param name="converterId" value="#{! empty cc.attrs.converterId ? cc.attrs.converterId : 'universalConverter'}" />
<ui:param name="validatorId" value="#{! empty cc.attrs.validatorId ? cc.attrs.validatorId : 'universalValidator'}" />
<ui:param name="component" value="#{formFieldBean.getComponent(cc.attrs.inputTextId)}" />
<ui:param name="componentValid" value="#{((facesContext.maximumSeverity == null and empty component.valid) or component.valid) ? true : false}" />
<ui:param name="requiredMessage" value="#{! empty cc.attrs.requiredMessage ? cc.attrs.requiredMessage : msg['validation.generic.requiredMessage']}" />
<ui:param name="clientIdEscaped" value="#{fn:replace(cc.clientId, ':', '\\\\\\\\:')}" />
<h:panelGroup layout="block" id="#{cc.attrs.inputTextId}ValidPanel" style="display:none;">
<input type="hidden" id="#{cc.attrs.inputTextId}Valid" value="#{componentValid}" />
</h:panelGroup>
<dm:outputLabel for="#{cc.clientId}:#{cc.attrs.inputTextId}" id="#{cc.attrs.inputTextId}Label">#{cc.attrs.labelText}</dm:outputLabel>
<dm:inputText
styleClass="#{cc.attrs.textBoxStyleClass}"
tabindex="#{cc.attrs.tabindex}"
id="#{cc.attrs.inputTextId}"
required="#{cc.attrs.required}"
requiredMessage="#{requiredMessage}"
title="#{cc.attrs.title}"
unicodeSupport="#{cc.attrs.unicodeSupport}">
<f:validator validatorId="#{validatorId}" />
<f:converter converterId="#{converterId}" />
<cc:insertChildren />
<f:ajax
event="blur"
execute="@this"
render="#{cc.attrs.inputTextId}ValidPanel #{cc.attrs.inputTextId}Msg"
onevent="on#{cc.attrs.inputTextId}Event" />
</dm:inputText>
<rich:message for="#{cc.clientId}:#{cc.attrs.inputTextId}" id="#{cc.attrs.inputTextId}Msg" style="display: none;" />
<script>
function on#{cc.attrs.inputTextId}Event(e) {
if(e.status == 'success') {
$('##{clientIdEscaped}\\:#{cc.attrs.inputTextId}').trigger($('##{cc.attrs.inputTextId}Valid').val()=='true'?'pass':'fail');
}
}
$('##{clientIdEscaped}\\:#{cc.attrs.inputTextId}').bind('fail', function() {
$('##{clientIdEscaped}\\:#{cc.attrs.inputTextId}, ##{clientIdEscaped}\\:#{cc.attrs.inputTextId}Label, ##{cc.attrs.inputTextId}Msg, ##{cc.id}Msg').addClass('error');
$('##{cc.id}Msg').html($('##{clientIdEscaped}\\:#{cc.attrs.inputTextId}Msg').html());
#{cc.attrs.onfail}
}).bind('pass', function() {
$('##{clientIdEscaped}\\:#{cc.attrs.inputTextId}, ##{clientIdEscaped}\\:#{cc.attrs.inputTextId}Label, ##{cc.attrs.inputTextId}Msg, ##{cc.id}Msg').removeClass('error');
$('##{cc.id}Msg').html($('##{clientIdEscaped}\\:#{cc.attrs.inputTextId}Msg').html());
#{cc.attrs.onpass}
});
</script>
<a4j:region rendered="#{facesContext.maximumSeverity != null and !componentValid}">
<script>
$(document).ready(function() {
$('##{clientIdEscaped}\\:#{cc.attrs.inputTextId}').trigger('fail');
});
</script>
</a4j:region>
</cc:implementation>
</html>
I'd like to be able to add an optional "listener" attribute which if defined would add an event listener to my f:ajax but I'm having trouble figuring out how to accomplish this. Any help would be appreciated.
Answer
You need to specify the method-signature attribute of the <cc:attribute> tag in order to treat the attribute value as a method expression. You can use the JSTL view build time tag <c:if> to conditionally add the <f:ajax> tag.
<cc:interface>
<cc:attribute name="listener" method-signature="void listener()" />
</cc:interface>
<cc:implementation>
<h:someComponent>
<c:if test="#{cc.getValueExpression('listener') != null}">
<f:ajax listener="#{cc.attrs.listener}" />
</c:if>
</h:someComponent>
</cc:implementation>
(the #{not empty cc.attrs.listener} won't work as EL would implicitly evaluate the attribute as a value expression)
Then you can use it as follows:
<my:someComposite listener="#{bean.listener}" />
Or when your environment doesn't support EL 2.2, then create a backing component:
@FacesComponent("someComponent")
public class SomeComponent extends UINamingContainer {
public boolean isHasListener() {
return getValueExpression("listener") != null;
}
}
which is to be declared and used as
<cc:interface type="someComponent">
<cc:attribute name="listener" method-signature="void listener()" />
</cc:interface>
<cc:implementation>
<h:someComponent>
<c:if test="#{cc.hasListener}">
<f:ajax listener="#{cc.attrs.listener}" />
</c:if>
</h:someComponent>
</cc:implementation>