The following code is inspired from PrimeFaces DataGrid + DataTable Tutorials and put into a <p:tab>
of a <p:tabView>
residing in a <p:layoutUnit>
of a <p:layout>
. Here is the inner part of the code (starting from p:tab
component); the outer part is trivial.
<p:tabView id="tabs">
<p:tab id="search" title="Search">
<h:form id="insTable">
<p:dataTable id="table" var="lndInstrument" value="#{instrumentBean.instruments}">
<p:column>
<p:commandLink id="select" update="insTable:display" oncomplete="dlg.show()">
<f:setPropertyActionListener value="#{lndInstrument}"
target="#{instrumentBean.selectedInstrument}" />
<h:outputText value="#{lndInstrument.name}" />
</p:commandLink>
</p:column>
</p:dataTable>
<p:dialog id="dlg" modal="true" widgetVar="dlg">
<h:panelGrid id="display">
<h:outputText value="Name:" />
<h:outputText value="#{instrumentBean.selectedInstrument.name}" />
</h:panelGrid>
</p:dialog>
</h:form>
</p:tab>
</p:tabView>
When I click the <p:commandLink>
, the code stops working and gives the message:
Cannot find component with expression "insTable:display" referenced from "tabs:insTable:select".
When I try the same using <f:ajax>
, it fails with a different message basically telling the same:
<f:ajax>
contains an unknown id "insTable:display" cannot locate it in the context of the component "tabs:insTable:select"
How is this caused and how can I solve it?
You need to look in the generated HTML output to find out the right client ID. Open the page in browser, do a rightclick and View Source. Locate the HTML representation of the JSF component of interest and take its id
as client ID. You can use it in an absolute or relative way depending on the current naming container. See following chapter.
Note: if it happens to contain iteration index like :0:
, :1:
, etc (because it's inside an iterating component), then you need to realize that updating a specific iteration round is not always supported. See bottom of answer for more detail on that.
NamingContainer
components and always give them a fixed IDIf a component which you'd like to reference by ajax process/execute/update/render is inside the same NamingContainer
parent, then just reference its own ID.
<h:form id="form">
<p:commandLink update="result"> <!-- OK! -->
<h:panelGroup id="result" />
</h:form>
If it's not inside the same NamingContainer
, then you need to reference it using an absolute client ID. An absolute client ID starts with the NamingContainer
separator character, which is by default :
.
<h:form id="form">
<p:commandLink update="result"> <!-- FAIL! -->
</h:form>
<h:panelGroup id="result" />
<h:form id="form">
<p:commandLink update=":result"> <!-- OK! -->
</h:form>
<h:panelGroup id="result" />
<h:form id="form">
<p:commandLink update=":result"> <!-- FAIL! -->
</h:form>
<h:form id="otherform">
<h:panelGroup id="result" />
</h:form>
<h:form id="form">
<p:commandLink update=":otherform:result"> <!-- OK! -->
</h:form>
<h:form id="otherform">
<h:panelGroup id="result" />
</h:form>
NamingContainer
components are for example <h:form>
, <h:dataTable>
, <p:tabView>
, <cc:implementation>
(thus, all composite components), etc. You recognize them easily by looking at the generated HTML output, their ID will be prepended to the generated client ID of all child components. Note that when they don't have a fixed ID, then JSF will use an autogenerated ID in j_idXXX
format. You should absolutely avoid that by giving them a fixed ID. The OmniFaces NoAutoGeneratedIdViewHandler
may be helpful in this during development.
If you know to find the javadoc of the UIComponent
in question, then you can also just check in there whether it implements the NamingContainer
interface or not. For example, the HtmlForm
(the UIComponent
behind <h:form>
tag) shows it implements NamingContainer
, but the HtmlPanelGroup
(the UIComponent
behind <h:panelGroup>
tag) does not show it, so it does not implement NamingContainer
. Here is the javadoc of all standard components and here is the javadoc of PrimeFaces.
So in your case of:
<p:tabView id="tabs"><!-- This is a NamingContainer -->
<p:tab id="search"><!-- This is NOT a NamingContainer -->
<h:form id="insTable"><!-- This is a NamingContainer -->
<p:dialog id="dlg"><!-- This is NOT a NamingContainer -->
<h:panelGrid id="display">
The generated HTML output of <h:panelGrid id="display">
looks like this:
<table id="tabs:insTable:display">
You need to take exactly that id
as client ID and then prefix with :
for usage in update
:
<p:commandLink update=":tabs:insTable:display">
If this command link is inside an include/tagfile, and the target is outside it, and thus you don't necessarily know the ID of the naming container parent of the current naming container, then you can dynamically reference it via UIComponent#getNamingContainer()
like so:
<p:commandLink update=":#{component.namingContainer.parent.namingContainer.clientId}:display">
Or, if this command link is inside a composite component and the target is outside it:
<p:commandLink update=":#{cc.parent.namingContainer.clientId}:display">
Or, if both the command link and target are inside same composite component:
<p:commandLink update=":#{cc.clientId}:display">
See also Get id of parent naming container in template for in render / update attribute
This all is specified as "search expression" in the UIComponent#findComponent()
javadoc:
A search expression consists of either an identifier (which is matched exactly against the id property of a
UIComponent
, or a series of such identifiers linked by theUINamingContainer#getSeparatorChar
character value. The search algorithm should operates as follows, though alternate alogrithms may be used as long as the end result is the same:
- Identify the
UIComponent
that will be the base for searching, by stopping as soon as one of the following conditions is met:
- If the search expression begins with the the separator character (called an "absolute" search expression), the base will be the root
UIComponent
of the component tree. The leading separator character will be stripped off, and the remainder of the search expression will be treated as a "relative" search expression as described below.- Otherwise, if this
UIComponent
is aNamingContainer
it will serve as the basis.- Otherwise, search up the parents of this component. If a
NamingContainer
is encountered, it will be the base.- Otherwise (if no
NamingContainer
is encountered) the rootUIComponent
will be the base.- The search expression (possibly modified in the previous step) is now a "relative" search expression that will be used to locate the component (if any) that has an id that matches, within the scope of the base component. The match is performed as follows:
- If the search expression is a simple identifier, this value is compared to the id property, and then recursively through the facets and children of the base
UIComponent
(except that if a descendantNamingContainer
is found, its own facets and children are not searched).- If the search expression includes more than one identifier separated by the separator character, the first identifier is used to locate a
NamingContainer
by the rules in the previous bullet point. Then, thefindComponent()
method of thisNamingContainer
will be called, passing the remainder of the search expression.
Note that PrimeFaces also adheres the JSF spec, but RichFaces uses "some additional exceptions".
"reRender" uses
UIComponent.findComponent()
algorithm (with some additional exceptions) to find the component in the component tree.
Those additional exceptions are nowhere in detail described, but it's known that relative component IDs (i.e. those not starting with :
) are not only searched in the context of the closest parent NamingContainer
, but also in all other NamingContainer
components in the same view (which is a relatively expensive job by the way).
prependId="false"
If this all still doesn't work, then verify if you aren't using <h:form prependId="false">
. This will fail during processing the ajax submit and render. See also this related question: UIForm with prependId="false" breaks <f:ajax render>.
It was for long time not possible to reference a specific iterated item in iterating components like <ui:repeat>
and <h:dataTable>
like so:
<h:form id="form">
<ui:repeat id="list" value="#{['one','two','three']}" var="item">
<h:outputText id="item" value="#{item}" /><br/>
</ui:repeat>
<h:commandButton value="Update second item">
<f:ajax render=":form:list:1:item" />
</h:commandButton>
</h:form>
However, since Mojarra 2.2.5 the <f:ajax>
started to support it (it simply stopped validating it; thus you would never face the in the question mentioned exception anymore; another enhancement fix is planned for that later).
This only doesn't work yet in current MyFaces 2.2.7 and PrimeFaces 5.2 versions. The support might come in the future versions. In the meanwhile, your best bet is to update the iterating component itself, or a parent in case it doesn't render HTML, like <ui:repeat>
.
PrimeFaces Search Expressions allows you to reference components via JSF component tree search expressions. JSF has several builtin:
@this
: current component@form
: parent UIForm
@all
: entire document@none
: nothingPrimeFaces has enhanced this with new keywords and composite expression support:
@parent
: parent component@namingcontainer
: parent UINamingContainer
@widgetVar(name)
: component as identified by given widgetVar
You can also mix those keywords in composite expressions such as @form:@parent
, @this:@parent:@parent
, etc.
PrimeFaces Selectors (PFS) as in @(.someclass)
allows you to reference components via jQuery CSS selector syntax. E.g. referencing components having all a common style class in the HTML output. This is particularly helpful in case you need to reference "a lot of" components. This only prerequires that the target components have all a client ID in the HTML output (fixed or autogenerated, doesn't matter). See also How do PrimeFaces Selectors as in update="@(.myClass)" work?