Containing div for JSF composite components - ajax

I have a number of composite components in my application, and from time to time, I need to reference those components as a whole. By default, composite components don't generate any additional mark up over their child components, so if you give a composite component an id attribute, it simply appends that id to the generated ids of the child components. I would like to reference the whole component by id (i.e. for use in jquery manipulation). JSF components do not allow EL in the id attribute, so to accomplish this, I have so far been wrapping my composite components in plain html divs as follows:
<ui:component ...
xmlns:cc="http://java.sun.com/jsf/composite"
...>
<cc:interface componentType="myComponent">
<cc:attribute name="process" type="java.lang.String" required="false" default="#form"/>
<cc:attribute name="update" type="java.lang.String" required="false" default="#form"/>
...
</cc:interface>
<cc:implementation>
<h:outputStylesheet name="myComponent.css" library="css/components" target="head"/>
<div id="#{cc.clientId}" class="myComponent #{cc.attrs.styleClass}">
... composite component implementation here ...
<p:dataTable id="note-history" styleClass="entity-notes-history" value="#{cc.notes}" var="note" paginator="true" paginatorAlwaysVisible="false"
paginatorPosition="bottom" rows="5" rendered="#{not empty cc.notes}" rowStyleClass="#{note.noteBaseType.word}">
...
<p:column rendered="#{note.noteBaseType == 'Warning' and not cc.attrs.displayOnly}" style="width: 8em;">
<p:commandButton actionListener="#{cc.cancelSeverity(note.id)}" process="#{cc.attrs.process}" update="#{cc.attrs.update} update="note-history" value="Reduce Severity"/>
</p:column>
</p:dataTable>
</div>
</cc:implementation>
And the component would be used as follows:
....
<ppa:myComponent id="myId" update="myId" />
....
Unfortunately, if I have any ajax (specifically p:ajax from primefaces) calls within the composite component, when I try to have them update the composite component by ID I get a "Cannot find component with identifier" exception. Is there any way to get JSF to auto generate a valid component and container for my composite components? I would really hate to have to generate two containing divs or spans (i.e. adding an h:panelGroup around the plain html div) just to get ajax working. Alternatively, is there a way to force JSF to allow dynamic ids on components?
Edit:
In response to BallusC's answer, I've edited the example code to be more clear in how the component is built and used, since given his answer it's entirely possible I'm just doing something that isn't allowed.

when I try to have them update the composite component by ID I get a "Cannot find component with identifier" exception
It's unfortunate that you didn't show how exactly you did that, because it should work just fine, provided that you used the composite's client ID in the update which is enclosed in the composite itself:
<f:ajax render=":#{cc.clientId}" />
Or, that you just used composite's own ID in the update which is performed outside the composite inside the same naming container parent:
<f:ajax render="myId" />
Most likely you did it the wrong way. E.g. you forgot the : prefix, or you used #{cc.id} instead of #{cc.clientId}, etc. The above has as far as I know always worked in all Mojarra 2.x versions released so far.
See also:
Referring composite component ID in f:ajax render
Is it possible to update non-JSF components (plain HTML) with JSF ajax?
Alternatively, is there a way to force JSF to allow dynamic ids on components?
You can just use EL in id attribute, provided that it's available during view build time and thus not only during view render time. See also JSTL in JSF2 Facelets... makes sense? for related background information.
Update as per your question update wherein you finally show how you tried to achieve it;
With
<ppa:myComponent id="myId" update="myId" />
and
<p:commandButton ... update="#{cc.attrs.update}" />
you're effectively ultimately doing a
<p:commandButton ... update="myId" />
which is basically looking for a component with ID myId inside the context of the composite itself! It would only have effect on e.g. a <h:outputText id="myID"> next to the <p:commandButton> inside the same <cc:implementation>.
The functional requirement is understood, but the solution is not so nice. Your closest bet is (ab)using #this and conditionally checking for that in update:
<ppa:myComponent id="myId" update="#this" />
with something like this
<p:commandButton ... update="#{cc.attrs.update == '#this' ? ':'.concat(cc.clientId) : cc.attrs.update}" />

Related

JSF rendering ajax outside of form [duplicate]

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>, then 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"
When it happens during another Ajax postback and the JSF project stage is set to Development, then it fails with a JavaScript alert with the message:
malformedXML: During update: insTable:display not found
How is this caused and how can I solve it?
Look in HTML output for actual client ID
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.
Memorize NamingContainer components and always give them a fixed ID
If 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.
Solving your problem
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">
Referencing outside include/tagfile/composite
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
How does it work under the covers
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 the UINamingContainer#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 a NamingContainer 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 root UIComponent 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 descendant NamingContainer 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, the findComponent() method of this NamingContainer 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).
Never use 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>.
Referencing specific iteration round of iterating components
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>.
When using PrimeFaces, consider Search Expressions or Selectors
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: nothing
PrimeFaces 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?
first of all: as far as i know placing dialog inside a tabview is a bad practice... you better take it out...
and now to your question:
sorry, took me some time to get what exactly you wanted to implement,
did at my web app myself just now, and it works
as I sayed before place the p:dialog out side the `p:tabView ,
leave the p:dialog as you initially suggested :
<p:dialog modal="true" widgetVar="dlg">
<h:panelGrid id="display">
<h:outputText value="Name:" />
<h:outputText value="#{instrumentBean.selectedInstrument.name}" />
</h:panelGrid>
</p:dialog>
and the p:commandlink should look like this (all i did is to change the update attribute)
<p:commandLink update="display" oncomplete="dlg.show()">
<f:setPropertyActionListener value="#{lndInstrument}"
target="#{instrumentBean.selectedInstrument}" />
<h:outputText value="#{lndInstrument.name}" />
</p:commandLink>
the same works in my web app, and if it does not work for you , then i guess there is something wrong in your java bean code...
It's because the tab is a naming container aswell... your update should be update="Search:insTable:display" What you can do aswell is just place your dialog outside the form and still inside the tab then it would be: update="Search:display"
Please note that from PrimeFaces 10 and up, you are able to use observer and event.
This allows you to update components based on a custom event name, set by the #obs(event) keyword. For example:
<p:commandButton update="#obs(myEvent)"/>
<h:panelGroup>
<p:autoUpdate on="myEvent"/>
</h:panelGroup>
See:
https://www.primefaces.org/showcase/ui/ajax/observer.xhtml
I know this already has a great answer by BalusC but here is a little trick I use to get the container to tell me the correct clientId.
Remove the update on your component that is not working
Put a temporary component with a bogus update within the component you were trying to update
hit the page, the servlet exception error will tell you the correct client Id you need to reference.
Remove bogus component and put correct clientId in the original update
Here is code example as my words may not describe it best.
<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"
Remove the failing update within this component
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">
Add a component within the component of the id you are trying to update using an update that will fail
<p:commandButton id="BogusButton" update="BogusUpdate"></p:commandButton>
<h:outputText value="Name:" />
<h:outputText value="#{instrumentBean.selectedInstrument.name}" />
</h:panelGrid>
</p:dialog>
</h:form>
</p:tab>
</p:tabView>
Hit this page and view the error.
The error is:
javax.servlet.ServletException: Cannot find component for expression "BogusUpdate" referenced from
tabs:insTable: BogusButton
So the correct clientId to use would then be the bold plus the id of the target container (display in this case)
tabs:insTable:display
Try change update="insTable:display" to update="display". I believe you cannot prefix the id with the form ID like that.

How to partially process pure JSF2 form with ajax? [duplicate]

What exactly are process and update in PrimeFaces p:commandXxx components and execute and render in f:ajax tag?
Which works at the time of validation? What does update attribute do rather than updating value to component from back end? Do process attribute bind value to model? What exactly do #this, #parent, #all and #form in both attributes?
The example below is working fine, but I am a little confused in basic concepts.
<p:commandButton process="#parent"
update="#form"
action="#{bean.submit}"
value="Submit" />
<p:commandXxx process> <p:ajax process> <f:ajax execute>
The process attribute is server side and can only affect UIComponents implementing EditableValueHolder (input fields) or ActionSource (command fields). The process attribute tells JSF, using a space-separated list of client IDs, which components exactly must be processed through the entire JSF lifecycle upon (partial) form submit.
JSF will then apply the request values (finding HTTP request parameter based on component's own client ID and then either setting it as submitted value in case of EditableValueHolder components or queueing a new ActionEvent in case of ActionSource components), perform conversion, validation and updating the model values (EditableValueHolder components only) and finally invoke the queued ActionEvent (ActionSource components only). JSF will skip processing of all other components which are not covered by process attribute. Also, components whose rendered attribute evaluates to false during apply request values phase will also be skipped as part of safeguard against tampered requests.
Note that it's in case of ActionSource components (such as <p:commandButton>) very important that you also include the component itself in the process attribute, particularly if you intend to invoke the action associated with the component. So the below example which intends to process only certain input component(s) when a certain command component is invoked ain't gonna work:
<p:inputText id="foo" value="#{bean.foo}" />
<p:commandButton process="foo" action="#{bean.action}" />
It would only process the #{bean.foo} and not the #{bean.action}. You'd need to include the command component itself as well:
<p:inputText id="foo" value="#{bean.foo}" />
<p:commandButton process="#this foo" action="#{bean.action}" />
Or, as you apparently found out, using #parent if they happen to be the only components having a common parent:
<p:panel><!-- Type doesn't matter, as long as it's a common parent. -->
<p:inputText id="foo" value="#{bean.foo}" />
<p:commandButton process="#parent" action="#{bean.action}" />
</p:panel>
Or, if they both happen to be the only components of the parent UIForm component, then you can also use #form:
<h:form>
<p:inputText id="foo" value="#{bean.foo}" />
<p:commandButton process="#form" action="#{bean.action}" />
</h:form>
This is sometimes undesirable if the form contains more input components which you'd like to skip in processing, more than often in cases when you'd like to update another input component(s) or some UI section based on the current input component in an ajax listener method. You namely don't want that validation errors on other input components are preventing the ajax listener method from being executed.
Then there's the #all. This has no special effect in process attribute, but only in update attribute. A process="#all" behaves exactly the same as process="#form". HTML doesn't support submitting multiple forms at once anyway.
There's by the way also a #none which may be useful in case you absolutely don't need to process anything, but only want to update some specific parts via update, particularly those sections whose content doesn't depend on submitted values or action listeners.
Noted should be that the process attribute has no influence on the HTTP request payload (the amount of request parameters). Meaning, the default HTML behavior of sending "everything" contained within the HTML representation of the <h:form> will be not be affected. In case you have a large form, and want to reduce the HTTP request payload to only these absolutely necessary in processing, i.e. only these covered by process attribute, then you can set the partialSubmit attribute in PrimeFaces Ajax components as in <p:commandXxx ... partialSubmit="true"> or <p:ajax ... partialSubmit="true">. You can also configure this 'globally' by editing web.xml and add
<context-param>
<param-name>primefaces.SUBMIT</param-name>
<param-value>partial</param-value>
</context-param>
Alternatively, you can also use <o:form> of OmniFaces 3.0+ which defaults to this behavior.
The standard JSF equivalent to the PrimeFaces specific process is execute from <f:ajax execute>. It behaves exactly the same except that it doesn't support a comma-separated string while the PrimeFaces one does (although I personally recommend to just stick to space-separated convention), nor the #parent keyword. Also, it may be useful to know that <p:commandXxx process> defaults to #form while <p:ajax process> and <f:ajax execute> defaults to #this. Finally, it's also useful to know that process supports the so-called "PrimeFaces Selectors", see also How do PrimeFaces Selectors as in update="#(.myClass)" work?
<p:commandXxx update> <p:ajax update> <f:ajax render>
The update attribute is client side and can affect the HTML representation of all UIComponents. The update attribute tells JavaScript (the one responsible for handling the ajax request/response), using a space-separated list of client IDs, which parts in the HTML DOM tree need to be updated as response to the form submit.
JSF will then prepare the right ajax response for that, containing only the requested parts to update. JSF will skip all other components which are not covered by update attribute in the ajax response, hereby keeping the response payload small. Also, components whose rendered attribute evaluates to false during render response phase will be skipped. Note that even though it would return true, JavaScript cannot update it in the HTML DOM tree if it was initially false. You'd need to wrap it or update its parent instead. See also Ajax update/render does not work on a component which has rendered attribute.
Usually, you'd like to update only the components which really need to be "refreshed" in the client side upon (partial) form submit. The example below updates the entire parent form via #form:
<h:form>
<p:inputText id="foo" value="#{bean.foo}" required="true" />
<p:message id="foo_m" for="foo" />
<p:inputText id="bar" value="#{bean.bar}" required="true" />
<p:message id="bar_m" for="bar" />
<p:commandButton action="#{bean.action}" update="#form" />
</h:form>
(note that process attribute is omitted as that defaults to #form already)
Whilst that may work fine, the update of input and command components is in this particular example unnecessary. Unless you change the model values foo and bar inside action method (which would in turn be unintuitive in UX perspective), there's no point of updating them. The message components are the only which really need to be updated:
<h:form>
<p:inputText id="foo" value="#{bean.foo}" required="true" />
<p:message id="foo_m" for="foo" />
<p:inputText id="bar" value="#{bean.bar}" required="true" />
<p:message id="bar_m" for="bar" />
<p:commandButton action="#{bean.action}" update="foo_m bar_m" />
</h:form>
However, that gets tedious when you have many of them. That's one of the reasons why PrimeFaces Selectors exist. Those message components have in the generated HTML output a common style class of ui-message, so the following should also do:
<h:form>
<p:inputText id="foo" value="#{bean.foo}" required="true" />
<p:message id="foo_m" for="foo" />
<p:inputText id="bar" value="#{bean.bar}" required="true" />
<p:message id="bar_m" for="bar" />
<p:commandButton action="#{bean.action}" update="#(.ui-message)" />
</h:form>
(note that you should keep the IDs on message components, otherwise #(...) won't work! Again, see How do PrimeFaces Selectors as in update="#(.myClass)" work? for detail)
The #parent updates only the parent component, which thus covers the current component and all siblings and their children. This is more useful if you have separated the form in sane groups with each its own responsibility. The #this updates, obviously, only the current component. Normally, this is only necessary when you need to change one of the component's own HTML attributes in the action method. E.g.
<p:commandButton action="#{bean.action}" update="#this"
oncomplete="doSomething('#{bean.value}')" />
Imagine that the oncomplete needs to work with the value which is changed in action, then this construct wouldn't have worked if the component isn't updated, for the simple reason that oncomplete is part of generated HTML output (and thus all EL expressions in there are evaluated during render response).
The #all updates the entire document, which should be used with care. Normally, you'd like to use a true GET request for this instead by either a plain link (<a> or <h:link>) or a redirect-after-POST by ?faces-redirect=true or ExternalContext#redirect(). In effects, process="#form" update="#all" has exactly the same effect as a non-ajax (non-partial) submit. In my entire JSF career, the only sensible use case I encountered for #all is to display an error page in its entirety in case an exception occurs during an ajax request. See also What is the correct way to deal with JSF 2.0 exceptions for AJAXified components?
The standard JSF equivalent to the PrimeFaces specific update is render from <f:ajax render>. It behaves exactly the same except that it doesn't support a comma-separated string while the PrimeFaces one does (although I personally recommend to just stick to space-separated convention), nor the #parent keyword. Both update and render defaults to #none (which is, "nothing").
See also:
How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"
Execution order of events when pressing PrimeFaces p:commandButton
How to decrease request payload of p:ajax during e.g. p:dataTable pagination
How to show details of current row from p:dataTable in a p:dialog and update after save
How to use <h:form> in JSF page? Single form? Multiple forms? Nested forms?
If you have a hard time remembering the default values (I know I have...) here's a short extract from BalusC's answer:
Component
Submit
Refresh
f:ajax
execute="#this"
render="#none"
p:ajax
process="#this"
update="#none"
p:commandXXX
process="#form"
update="#none"
By process (in the JSF specification it's called execute) you tell JSF to limit the processing to component that are specified every thing else is just ignored.
update indicates which element will be updated when the server respond back to you request.
#all : Every component is processed/rendered.
#this: The requesting component with the execute attribute is processed/rendered.
#form : The form that contains the requesting component is processed/rendered.
#parent: The parent that contains the requesting component is processed/rendered.
With Primefaces you can even use JQuery selectors, check out this blog: http://blog.primefaces.org/?p=1867
JSF 2.0+ keywords
#this Current component.
#all Whole view.
#form Closest ancestor form of current component.
#none No component.
JSF 2.3+ keywords
#child(n) nth child.
#composite Closest composite component ancestor.
#id(id) Used to search components by their id ignoring the component tree structure and naming containers.
#namingcontainer Closest ancestor naming container of current component.
#parent Parent of the current component.
#previous Previous sibling.
#next Next sibling.
#root UIViewRoot instance of the view, can be used to start searching from the root instead the current component.
PrimeFaces specific keywords
#row(n) nth row.
#widgetVar(name) Component with given widgetVar.
And you can even use something called "PrimeFaces Selectors" which allows you to use jQuery Selector API. For example to process all inputs in a element with the CSS class myClass:
process="#(.myClass :input)"
See:
https://primefaces.github.io/primefaces/12_0_0/#/core/searchexpression
PrimeFaces 10+ Observer / Event
This allows you to update components based on a custom event name, set by the #obs(event) keyword. For example:
<p:commandButton update="#obs(myEvent)"/>
<h:panelGroup>
<p:autoUpdate on="myEvent"/>
</h:panelGroup>
See:
https://www.primefaces.org/showcase/ui/ajax/observer.xhtml
These are PrimeFaces features to provide partial view processing and partial rendering. You can control what to execute in lifecycle and what to render with ajax.
When using backing bean properties in expression language
process attribute calls SETTER methods
update attribute calls GETTER methods
primefaces forum

Rerendering composite component by ajax

I have build a composite component witch looks something like this:
<composite:interface>
<composite:attribute name="id" required="false" />
<composite:attribute name="label" required="true" />
</composite:interface>
<composite:implementation>
<h:panelGroup id="#{cc.attrs.id}">
<fieldset class="fieldset"><legend>${cc.attrs.label}</legend></fieldset>
</h:panelGroup>
</composite:implementation>
The compent displays the current label correctly.
<xyz:comp id="idMyComponent" label="#{someBean.text}"/>
...
<a4j:ajax ... render="idMyComponent" />
...
Now when the action is preformed nothing happens. However when I add a Postfix to the ID in the component it works fine (see below).
...
<composite:implementation>
<h:panelGroup id="#{cc.attrs.id}Label">
...
And define the ID in render with the postfix:
<xyz:comp id="idMyComponent" label="#{someBean.text}"/>
...
<a4j:ajax ... render="idMyComponentLabel" />
...
Can some on explain to me why it only works when I add a postfix to the ID in h:panelGroup?
This problem is actually two-fold.
The first problem is that the <xyz:comp id> actually specifies the ID of the composite component itself, the <cc:implementation>. This is by default nowhere represented in HTML output and therefore ajax/JavaScript can't locate it by document.getElementById() and friends.
Actually, your <h:panelGroup id="#{cc.attrs.id}"> ends up in generated HTML output as follows (rightclick page and View Source to see it yourself):
<span id="idMyComponent:idMyComponent">
The second "problem" is that RichFaces/Ajax4jsf has enhanced the referencing/finding of JSF components in the tree by relative client ID (i.e. not starting with :) by not only searching in the context of the current NamingContainer, but also in all other NamingContainer components. A composite component is inherently also a NamingContainer component.
Your first attempt failed because it found the composite itself instead of the panel group, but JS/ajax in turn failed to update because there doesn't exist any HTML element with id="myComponent" in the generated HTML output.
Your second attempt succeeded because it finally found the real panel group (note: because it also searched in all other NamingContainer components; this would still have failed if you've used <f:ajax> instead of <a4j:ajax>).
The right way to fix your problem is not using #{cc.attrs.id} on a JSF component, but using #{cc.clientId} on a plain HTML element.
<span id="#{cc.clientId}">
(yes, use a <span> or <div> instead of <h:panelGroup> inside the <cc:implementation>)
This way JSF can find the component by client ID (in order to generate the proper ajax response) and JS can find the HTML element by client ID (in order to update the right HTML element based on ajax response).
See also:
Is it possible to update non-JSF components (plain HTML) with JSF ajax?
Integrate JavaScript in JSF composite component, the clean way
How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"

Value to update attribute of primefaces command button

I have a query here regarding the value given to the update attribute of the primefaces command button.
Here is a simple code. I have a simple xhtml page
<h:body>
<h:form id="main">
<p:growl id="maingrowl" showDetail="true"></p:growl>
<p:panelGrid id="mainpanel" columns="2">
<p:commandButton value="Ajax Submit" update="test" id="ajax"
actionListener="#{mytestBean.display}" />
</p:panelGrid>
<p:panelGrid id="test" rendered="#{mytestBean.show}" columns="1">
<h:inputText value="#{mytestBean.val1}" />
<h:inputText value="#{mytestBean.val2}" />
<p:commandButton value="value in" id="aj" update="test"
actionListener="#{mytestBean.displaysec}">
</p:commandButton>
</p:panelGrid>
</h:form>
</h:body>
Now, If I have to update the panelgrid "test" then in the first command button I have to provide the id "test" prefixed with ":main:" in the update attribute of the command button since that is the exact id in the HTML DOM as I find it in the view source in the browser. But, I was able to update even by given just "test" in the update attribute.
So my question here is when should I use the ":" in the id or is it mandatory or is there any pre defined rule to give the id's in the attribute?
Also, I am aware of the fact that the id given in the update attribute is through the UINamingContainer in which it is placed. Please pardon me if its trivial, I am really confused here.
Any help greatly appreciated.
Thank you.
If both components (the one to update and the one that triggers the update) are inside the same NamingContainer, the relative client id withoud the : is sufficient.
NamingContainers in jsf are all those components that prepend their own id to the client id of all child components, e.g. <h:form>, <h:dataTable> or <ui:repeat> (or to be more precise: all components that implement the javax.faces.component.NamingContainer interface).
If both components are not inside the same NamingContainer, you have to use the absolute id beginning with a : from the view root.
If you are interested in more detailed information I recommend reading the javadoc of the UIComponent#findComponent() method where the search algorithm is described.
Note that the : is the default character to separate segments of a clientId. You can change it with a context parameter in your web.xml.

How to find out client ID of component for ajax update/render? Cannot find component with expression "foo" referenced from "bar"

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>, then 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"
When it happens during another Ajax postback and the JSF project stage is set to Development, then it fails with a JavaScript alert with the message:
malformedXML: During update: insTable:display not found
How is this caused and how can I solve it?
Look in HTML output for actual client ID
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.
Memorize NamingContainer components and always give them a fixed ID
If 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.
Solving your problem
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">
Referencing outside include/tagfile/composite
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
How does it work under the covers
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 the UINamingContainer#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 a NamingContainer 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 root UIComponent 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 descendant NamingContainer 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, the findComponent() method of this NamingContainer 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).
Never use 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>.
Referencing specific iteration round of iterating components
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>.
When using PrimeFaces, consider Search Expressions or Selectors
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: nothing
PrimeFaces 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?
first of all: as far as i know placing dialog inside a tabview is a bad practice... you better take it out...
and now to your question:
sorry, took me some time to get what exactly you wanted to implement,
did at my web app myself just now, and it works
as I sayed before place the p:dialog out side the `p:tabView ,
leave the p:dialog as you initially suggested :
<p:dialog modal="true" widgetVar="dlg">
<h:panelGrid id="display">
<h:outputText value="Name:" />
<h:outputText value="#{instrumentBean.selectedInstrument.name}" />
</h:panelGrid>
</p:dialog>
and the p:commandlink should look like this (all i did is to change the update attribute)
<p:commandLink update="display" oncomplete="dlg.show()">
<f:setPropertyActionListener value="#{lndInstrument}"
target="#{instrumentBean.selectedInstrument}" />
<h:outputText value="#{lndInstrument.name}" />
</p:commandLink>
the same works in my web app, and if it does not work for you , then i guess there is something wrong in your java bean code...
It's because the tab is a naming container aswell... your update should be update="Search:insTable:display" What you can do aswell is just place your dialog outside the form and still inside the tab then it would be: update="Search:display"
Please note that from PrimeFaces 10 and up, you are able to use observer and event.
This allows you to update components based on a custom event name, set by the #obs(event) keyword. For example:
<p:commandButton update="#obs(myEvent)"/>
<h:panelGroup>
<p:autoUpdate on="myEvent"/>
</h:panelGroup>
See:
https://www.primefaces.org/showcase/ui/ajax/observer.xhtml
I know this already has a great answer by BalusC but here is a little trick I use to get the container to tell me the correct clientId.
Remove the update on your component that is not working
Put a temporary component with a bogus update within the component you were trying to update
hit the page, the servlet exception error will tell you the correct client Id you need to reference.
Remove bogus component and put correct clientId in the original update
Here is code example as my words may not describe it best.
<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"
Remove the failing update within this component
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">
Add a component within the component of the id you are trying to update using an update that will fail
<p:commandButton id="BogusButton" update="BogusUpdate"></p:commandButton>
<h:outputText value="Name:" />
<h:outputText value="#{instrumentBean.selectedInstrument.name}" />
</h:panelGrid>
</p:dialog>
</h:form>
</p:tab>
</p:tabView>
Hit this page and view the error.
The error is:
javax.servlet.ServletException: Cannot find component for expression "BogusUpdate" referenced from
tabs:insTable: BogusButton
So the correct clientId to use would then be the bold plus the id of the target container (display in this case)
tabs:insTable:display
Try change update="insTable:display" to update="display". I believe you cannot prefix the id with the form ID like that.

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