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How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"
(6 answers)
Closed 2 years ago.
When I click addTagButton, everything works well. It updates all three components: tags, tagId and addTagButton.
<p:commandButton id="addTagButton" icon="ui-icon-plus"
action="#{searchBean.addTag}"
update="tags, tagId, addTagButton"
disabled="#{searchBean.tagChoices.size() == 0}">
</p:commandButton>
Here's the table component:
<h:dataTable id="tags" var="tag" value="#{searchBean.tags}">
<h:column>
<div style="text-align:right;">
<h:outputLabel value="#{tag.typeName}:"/>
</div>
</h:column>
<h:column>
<p:inputText id="tag" size="25" value="#{tag.typeValue}"
disabled="#{searchBean.searchForParent}"/>
</h:column>
<h:column>
<p:commandButton id="delTagButton" icon="pi pi-trash"
action="#{searchBean.deleteTag}"
update=":contentForm:tagId, :contentForm:addTagButton, tags">
<f:setPropertyActionListener
target="#{searchBean.tagId}"
value="#{tag.typeName}" />
</p:commandButton>
</h:column>
</h:dataTable>
When i click on delTagButton that is on each row in tags table, action works fine, :contentForm:tagId and :contentForm:addTagButton update fine. But tags table which is where clicked command button exist, does not update.
When a row is deleted, change must reflect in the tags table which does not work.
Now, If I change h:dataTable to p:dataTable or any other primefaces component, it works. I am trying to make it work with h:dataTable.
Primefaces 8.0, JSF 2.5
Look on this simple example:
<h:form id="form">
<h:panelGroup id="wrapper" layout="block">
<h:dataTable id="table" border="1" value="#{testBean.list}" var="person">
<h:column>#{person.name}</h:column>
<h:column>#{person.surname}</h:column>
<h:column>
<p:commandButton id="delTagButton" icon="pi pi-trash"
action="#{testBean.remove(person)}" update="table">
</p:commandButton>
</h:column>
</h:dataTable>
</h:panelGroup>
</h:form>
To really find out what is being updated look in browser console.
If you're trying to update="table" nothing happens (like in your code). If you try to update a parent of the table (which is often a case), you will get an error an error:
SEVERE: Error Rendering View[/example.xhtml]
org.primefaces.expression.ComponentNotFoundException: Cannot find component for expression "wrapper" referenced from "form:table:0:delTagButton".
at org.primefaces.expression.SearchExpressionFacade.cannotFindComponent(SearchExpressionFacade.java:677)
So we could try with "older" parent and realize that update="#form" works! OK, so we want to help to find id="table\wrapper" component. Let try clientId update="form:table". Like with update="table" nothing happens. And no error from PF (so the element can be found). This could mean that h:dataTable cannot be properly re-rendered from inside itself (but I don't want to throw stones:-)). This is often a case with e.g. popups in JSF 3rd party component libraries.
In this particular example I'd say, you have to update form:wrapper (adding form: works) or just #form to get it work. With your code it would be the same. Try to update some table parent or the whole form.
All of above is tested in JSF 2.2, with last RF, an old PF and OmniFaces. But I think the same would be the case with newer versions.
BTW. I didn't know there is JSF 2.5 :-)
I have a datatable using rowExpansion.
When the page is loaded, the rowExpansion is not evaluated, which is fine.
When the paginator is used to show the next results or if a submission is done - the rowExpansion evaluation is triggered.
Here is a XHTML example :
<h:form>
<p:dataTable var="data" value="#{bean.dataList}" paginator="true">
<p:column headerText="Details">
<p:rowToggler />
</p:column>
<p:rowExpansion>
<h:panelGroup rendered="#{not empty data.detail}">
<ui:include src="dataDetail.xhtml" />
</h:panelGroup>
</p:rowExpansion>
</p:dataTable>
<h:commandLink id="addData" value="Add data" action="#{bean.addData}" />
</h:form>
I've profiled this flow using visualVM, and used the debugger, to discover that the data.getDetail() method was called during the following JSF phases : (ApplyRequestValuesPhase, ProcessValidationsPhase, UpdateModelValuesPhase), when the paginator was used.
I've come to the deduction that the rowExpansion is part of the view, and is evaluated as a normal component.
Would you mind telling me if it is the expected behaviour for rowExpansion ?
Is there a correct way to prevent the evaluation of the rowExpansion content when using the paginator ?
Thanks for your answers.
NB : I'm using PrimeFaces 5.2.
I have next a4j:jsFunction
<a4j:jsFunction name="renderOnBusinessErrorEvent" execute="#none" bypassUpdates="true" immediate="true"
render="securityForm">
</a4j:jsFunction>
and JSF form with some dialog inside
<h:form id="securityForm">
<h:panelGroup rendered="#{someCondition}">
......
</h:panelGroup>
</h:form>
In my business logic it has to be executed twice consequently. In the first time all is fine. Rendered method is invoked and the expected dialog is present on the page. In the second time rendered method is not invoked, but model has been changed and I expect that dialog will not be present on the page. I supposed that it's some richfaces issue and I tried to use f:ajax
<a4j:jsFunction name="renderOnBusinessErrorEvent" execute="#none" bypassUpdates="true" immediate="true">
<f:ajax event="begin" render=":securityForm"/>
</a4j:jsFunction>
but unsuccessfully. Rendered method still not invoked in the second time. What is it? Some JSF optimization or bug? What's the workaround?
JSF version 2.1.19
The problem was in <h:panelGroup rendered="#{someOtherCondition}">
over h:form which equals false after the first rendering (ON THE SERVER SIDE).
However, this panelGroup is not part of rendering. So, my code:
<h:panelGroup rendered="#{someOtherCondition}">
<h:form id="securityForm">
<h:panelGroup rendered="#{someCondition}">
......
</h:panelGroup>
</h:form>
</h:panelGroup>
<h:form>
<a4j:jsFunction name="renderOnBusinessErrorEvent" execute="#none" bypassUpdates="true" immediate="true"
render="securityForm">
</a4j:jsFunction>
</h:form>
Before calling renderOnBusinessErrorEvent() I'm changing the value of someOtherCondition from true to false, but I don't rerender this element. Actually, on the server side this element is already missing. Looks like it's JSF feature, but is it specificated somewhere?
I have following code:
<ui:repeat var="class2" value="#{bean.list}" varStatus="status">
<h:form id="#{class2.name}">
<h:outputText value="#{class2.name}" />
</h:form>
</ui:repeat>
However, when I open the page, it errors as follows:
component identifier must not be a zero-length String
But it is properly printed in the <h:outputText>. How is this caused and how can I solve it?
You can use EL in the id attribute of a JSF component, but the EL variable has to be available during view build time, while the JSF component tree is to be built. However, the <ui:repeat> runs during view render time, while the HTML output is to be generated based on JSF component tree. The <ui:repeat var> is not available during view build time and #{class2.name} evaluates to null which totally explains the error you got. That it works in <h:outputText> is because it runs during view render time.
If you replace <ui:repeat> by <c:forEach>, which runs during view build time, then it'll work as you intented. The <c:forEach> will namely generate physically multiple <h:form> components in the JSF component tree which each generate individually their own HTML output (in contrary to <ui:repeat>, wherein the very same <h:form> component is been reused multiple times to generate HTML output).
<c:forEach var="class2" items="#{bean.list}" varStatus="status">
<h:form id="#{class2.name}">
<h:outputText value="#{class2.name}" />
</h:form>
</c:forEach>
However, I really wonder why you need to do that. There's usually no need to dynamically assign component IDs. JSF will already ensure the uniqueness of the ID. The below example,
<ui:repeat var="class2" value="#{bean.list}" varStatus="status">
<h:form id="form">
<h:outputText value="#{class2.name}" />
</h:form>
</ui:repeat>
will end up in multiple forms with each an unique ID, suffixed with iteration index of the <ui:repeat>. If you actually need to use #{class2.name} for some JavaScript/jQuery purposes (you did nowhere state the concrete functional requirement in the question for which you thought that this would be the right solution, so it's merely guessing), then just wrap it in a plain vanilla HTML element:
<ui:repeat var="class2" value="#{bean.list}" varStatus="status">
<div id="#{class2.name}">
<h:form id="form">
<h:outputText value="#{class2.name}" />
</h:form>
</div>
</ui:repeat>
Or set it as style class of a JSF component, which is also just selectable via a CSS selector:
<ui:repeat var="class2" value="#{bean.list}" varStatus="status">
<h:form id="form" styleClass="#{class2.name}">
<h:outputText value="#{class2.name}" />
</h:form>
</ui:repeat>
See also:
JSTL in JSF2 Facelets... makes sense?
I would like to be able to conditionally omit a footer from a PrimeFaces panel element:
<p:panel header="some text">
<f:facet name="footer">
#{message}
</f:facet>
<!-- ... -->
</p:panel>
I hoped that the rendered attribute would work:
<p:panel header="some text">
<f:facet name="footer" rendered="#{!empty message}">
#{message}
</f:facet>
<!-- ... -->
</p:panel>
But the footer is still rendered, with empty content. It appears that facet does not have the rendered attribute: http://www.jsftoolbox.com/documentation/help/12-TagReference/core/f_facet.html.
What's the right way to do this?
I was able to solve this by swapping the facet out for an attribute. To summarize:
This works
<p:panel ...>
<f:attribute name="footer" value="#{message}"/>
<!-- ... -->
</p:panel>
But this doesn't work
<p:panel footer="#{message}">
<!-- ... -->
</p:panel>
Neither does this
<p:panel ...>
<f:facet name="footer">#{message}</f:facet>
<!-- ... -->
</p:panel>
Nor this
<p:panel ...>
<f:facet name="footer">
<h:outputText value="#{message}" rendered="#{!empty message}"/>
</f:facet>
<!-- ... -->
</p:panel>
by "works" I mean:
"renders no footer — not just an empty footer — when #{message} is empty or null; otherwise, correctly renders the footer with the specified text."
PrimeFaces forum thread on this issue
You could declare a ui:param and let the template check the param while renderring.
The facet in the template could then be declared as:
<f:facet name="#{hideFooter == null or not hideFooter ? 'footer' : ''}">
#{message}
</f:facet>
Any page can then declare this param
<ui:param name='hideFooter' value='#{some rule}' />
and set the appropriate rule for the param. For any page that does not declare the param, the footer will be displayed.
Here's what I did in trying to conditionally render a facet within a composite component.
<composite:interface>
<composite:facet name="header" required="false" />
</composite:interface>
<composite:implementation>
<p:panel>
<c:if test="#{empty component.facets.header}" >
<f:facet id="#{cc.attrs.id}_default_header" name="header">
all sorts of stuff here
</f:facet>
</c:if>
<c:if test="#{not empty component.facets.header}">
<composite:insertFacet id="#{cc.attrs.id}_custom_header" name="header" />
</c:if>
<composite:insertChildren id="#{cc.attrs.id}_content"/>
</p:panel>
</composite:implementation>
This let's the user of the composite component supply the header facet if they want, and if they don't, we supply a default. Obviously, instead of providing a default, you could simply not do anything.
This mixes c:if in jsf controls, but we didn't see any adverse effects.
I have come across a similar issue with plain JSF. I am not sure how a <p:panel> is rendered, but if it is rendered as a table, you can try this:
First, declare a CSS-class like this:
.HideFooter tfoot {
display: none;
}
Then set that class conditionally on the panel:
<p:panel styleClass="#{renderFooterCondition ? null : 'HideFooter'}">
The footer is still rendered in the JSF-sense, but it is not displayed and does not take up any space in the page when viewed by the user-agent.
I successfully solved this problem using ui:fragment
<ui:fragment rendered="...Test...">
<f:facet name="footer">
...
</f:facet>
</ui:fragment>
works for example to conditionnaly render the footer of a primefaces datatable (the rendered attribute of the facet does not work).
Not sure how well this would work for your footer, but I had the same issue with a legend I was trying to conditionally render. I fixed it by using the rendered on anything inside the facet tag.
<p:fieldset>
<f:facet name="legend">
<h:outputText value="#{header1}" rendered="#{header1.exists}"/>
<h:outputText value="#{header2}" rendered="#{not header1.exists}"/>
</f:facet>
content
</p:fieldset>
I had difficulty trying c:if with my ui:repeat, so this was my solution. Not quite the same as your problem, but similar.
Facets are not intended to render HTML, which is why it doesn't have the rendered attribute. Facets add functionality to a page. The term facet is probably a poor choice of name. It's very ambiguous.
..if the list compiled by ITworld's Phil Johnson has it right, the
single hardest thing developers do is name things.
ie.
JSF facets
A project facet is a specific unit of functionality that you can add to a project when that functionality is required. When a project facet is added to a project, it can add natures, builders, classpath entries, and resources to a project, depending on the characteristics of the particular project. JSF facets define the characteristics of your JSF enabled web application. The JSF facets specify the requirements and constraints that apply to your JSF project.
The JSF facets supply a set behaviors and capabilities to your web application.
This is a counter-answer to the answer from Ludovic Pénet.
This worked for me in <f:facet name="footer"> in selected p:column items of a p:dataTable (Primefaces 5.3):
...
Note how I have the ui:fragment inside the f:facet, not outside (not wrapping) it. It definitely completely removes the entire row when every footer facet is tested to NOT render (as far as I can tell, independent of the content within the ui:fragment).
Try with this, from primefaces web page
<p:columnGroup type="footer">
<p:row>
<p:column colspan="3" style="text-align:right" footerText="Totals:" />
<p:column footerText="your value in ajax" />
<p:column footerText="your value in ajax" />
</p:row>
</p:columnGroup>
clik here, to view primefaces' webpage
For those who landed here trying to hide the footer, instead of header, but the syntax component.facets.footer didn't work, should try this:
<p:panel id="panelContent">
<c:if test="#{not empty cc.facets.footer}">
<f:facet name="footer" height="100%">
your content
</f:facet>
</c:if>
</panel>
Why don't you enclose the content of the footer into a panelGroup which has the rendered attribute?
This way:
<p:panel header="some text">
<f:facet name="footer">
<h:panelGroup rendered="#{!empty message}">
#{message}
</h:panelGroup>
</f:facet>
<!-- ... -->
</p:panel>
I do it in my weapp and it works, no footer is rendered.
I don't use primefaces though, I do it with h:datatable, but I think that it must works with p:panel too.
I try this solution and ok. (http://www.coderanch.com/t/431222/JSF/java/dynamically-set-panel-header-condition)
<rich:dataGrid value="#{myMB.student.list}" rendered="#{!empty myMB.student and !empty myMB.student.list}" var="st" rowKeyVar="row">
<rich:panel>
<f:facet name="header">
<h:panelGroup id="panelHeader">
<h:outputText value="Just one student" id="header1" required="true" rendered="#{!myMB.manyStudents}"/>
<h:outputText value="#{row+1}º Student" id="header2" required="true" rendered="#{myMB.manyStudents}"/>
</h:panelGroup>
</f:facet>
<rich:panel>