Understanding PrimeFaces process/update and JSF f:ajax execute/render attributes -

what process , update in primefaces p:commandxxx components , execute , render in f:ajax tag?

which works @ time of validation? update attribute rather updating value component end? process attribute bind value model? @this, @parent, @all , @form in both attributes?

the example below working fine, 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 server side , can affect uicomponents implementing editablevalueholder (input fields) or actionsource (command fields). process attribute tells jsf, using space-separated list of client ids, components must processed through entire jsf lifecycle upon (partial) form submit.

jsf apply request values (finding http request parameter based on component's own client id , either setting submitted value in case of editablevalueholder components or queueing new actionevent in case of actionsource components), perform conversion, validation , updating model values (editablevalueholder components only) , invoke queued actionevent (actionsource components only). jsf skip processing of other components not covered process attribute. also, components rendered attribute evaluates false during apply request values phase skipped part of safeguard against tampered requests.

note it's in case of actionsource components (such <p:commandbutton>) important include component in process attribute, particularly if intend invoke action associated component. below example intends process input component(s) when command component invoked ain't gonna work:

<p:inputtext id="foo" value="#{bean.foo}" /> <p:commandbutton process="foo" action="#{bean.action}" />

it process #{bean.foo} , not #{bean.action}. you'd need include command component well:

<p:inputtext id="foo" value="#{bean.foo}" /> <p:commandbutton process="@this foo" action="#{bean.action}" />

or, apparently found out, using @parent if happen components having common parent:

<p:panel><!-- type doesn't matter, long it's common parent. -->     <p:inputtext id="foo" value="#{bean.foo}" />     <p:commandbutton process="@parent" action="#{bean.action}" /> </p:panel>

or, if both happen components of parent uiform component, can use @form:

<h:form>     <p:inputtext id="foo" value="#{bean.foo}" />     <p:commandbutton process="@form" action="#{bean.action}" /> </h:form>

this undesirable if form contains more input components you'd skip in processing, more in cases when you'd update input component(s) or ui section based on current input component in ajax listener method. namely don't want validation errors on other input components preventing ajax listener method being executed.

then there's @all. has no special effect in process attribute, in update attribute. process="@all" behaves same process="@form". html doesn't support submitting multiple forms @ once anyway.

there's way @none may useful in case absolutely don't need process anything, only want update specific parts via update, particularly sections content doesn't depend on submitted values or action listeners.

the standard jsf equivalent primefaces specific process execute <f:ajax execute>. behaves same except doesn't support comma-separated string while primefaces 1 (although recommend stick space-separated convention), nor @parent keyword. also, may useful know <p:commandxxx process> defaults @form while <p:ajax process> , <f:ajax execute> defaults @this. finally, it's useful know process supports so-called "primefaces selectors", see how primefaces selectors in update="@(.myclass)" work?

`<p:commandxxx update>` `<p:ajax update>` `<f:ajax render>`

the update attribute client side , can affect html representation of uicomponents. update attribute tells javascript (the 1 responsible handling ajax request/response), using space-separated list of client ids, parts in html dom tree need updated response form submit.

jsf prepare right ajax response that, containing only requested parts update. jsf skip other components not covered update attribute in ajax response, hereby keeping response payload small. also, components rendered attribute evaluates false during render response phase skipped. note though return true, javascript cannot update in html dom tree if false. you'd need wrap or update parent instead. see ajax update/render not work on component has rendered attribute.

usually, you'd update only components really need "refreshed" in client side upon (partial) form submit. example below updates 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 process attribute omitted defaults @form already)

whilst may work fine, update of input , command components in particular example unnecessary. unless change model values foo , bar inside action method (which in turn unintuitive in ux perspective), there's no point of updating them. message components really need 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, gets tedious when have many of them. that's 1 of reasons why primefaces selectors exist. message components have in generated html output common style class of ui-message, following should 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 should keep ids on message components, otherwise @(...) won't work! again, see how primefaces selectors in update="@(.myclass)" work? detail)

the @parent updates parent component, covers current component , siblings , children. more useful if have separated form in sane groups each own responsibility. @this updates, obviously, current component. normally, necessary when need change 1 of component's own html attributes in action method. e.g.

<p:commandbutton action="#{bean.action}" update="@this"      oncomplete="dosomething('#{bean.value}')" />

imagine oncomplete needs work value changed in action, construct wouldn't have worked if component isn't updated, simple reason oncomplete part of generated html output (and el expressions in there evaluated during render response).

the @all updates entire document, should used care. normally, you'd use true request instead either plain link (<a> or <h:link>) or redirect-after-post ?faces-redirect=true or externalcontext#redirect(). in effects, process="@form" update="@all" has same effect non-ajax (non-partial) submit. in entire jsf career, sensible use case encountered @all display error page in entirety in case exception occurs during ajax request. see what correct way deal jsf 2.0 exceptions ajaxified components?

the standard jsf equivalent primefaces specific update render <f:ajax render>. behaves same except doesn't support comma-separated string while primefaces 1 (although recommend stick space-separated convention), nor @parent keyword. both update , render defaults @none (which is, "nothing").

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