I'm using an <h:outputLink> as follows.
<c:set var="cid" value="1"/>
<c:set var="sid" value="2"/>
<h:outputLink value="Test.jsf">
<h:outputText value="Link"/>
<f:param name="cid" value="#{cid}"/>
<f:param name="sid" value="#{sid}"/>
</h:outputLink>
This is just an example. Both of the query-string parameters are dynamic. So, <c:set> used here is just for the sake of demonstration.
At any time, either one, both or none of the parameters may be present. In case, if only one or none of them is present then, parameter/s are unnecessarily appended to the URL which should not happen. Preventing unnecessary query-string parameters from being appended to the URL requires a conditional rendering of <f:param>.
JSTL <c:if> like the following
<c:if test="${not empty cid}">
<f:param name="cid" value="#{cid}"/>
</c:if>
did not work.
How can it be made possible to conditionally render <f:param> inside <h:outputLink>?
The <f:param> has a disable (not disabled!) attribute for the purpose.
<f:param name="cid" value="#{cid}" disable="#{empty cid}" />
<f:param name="sid" value="#{sid}" disable="#{empty sid}" />
Note that this has a bug in Mojarra versions older than 2.1.15, because they typo'ed the actual UIParameter property to be disble instead of disable. See also issue 2312.
As to the <c:if> approach, that would only work if the #{cid} and #{sid} is available during view build time. In other words, it would fail if they are only available during view render time, e.g. when they depend on var of a repeater component. See also JSTL in JSF2 Facelets... makes sense?
See also:
f:param tag attribute 'disable' is not work
Don't you like this kind of a solution?
<f:param name="#{cid == null ? '' : 'cid'}" value="#{cid}"/>
<f:param name="#{sid == null ? '' : 'sid'}" value="#{sid}"/>
Related
I am using jsf primefaces. I want to display an image depending on the value of a specific outputext. If the text value is 'Alarm *' then a div will appear whith a spesific image. If the value is 'Alarm **' then a div with an other image will appear, etc. I tried the code below but it does not work for me.
<h:outputText id="alarmCriticalityValue" value="#{msg[summary.criticality.key]}" />
<c:if test="#{alarmCriticalityValue=='Alarm *'}">
<div class="alarm1"></div>
</c:if>
How should i implement this idea?
You need to use binding attribute to put the UIComponent instance in the EL scope. The id attribute doesn't do that, on contrary to what you expected.
<h:outputText binding="#{alarmCriticality}" ... />
And then you need to use UIOutput#getValue() to obtain its value attribute.
<c:if test="#{alarmCriticality.value == 'Alarm *'}">
That said, you'd better use rendered attribute here, particularly if #{summary} represents the currently iterated item of a JSF iterating component like <ui:repeat> or <h:dataTable>.
<h:panelGroup layout="block" styleClass="alarm1"
rendered="#{alarmCriticality.value == 'Alarm *'}" />
See also:
How does the 'binding' attribute work in JSF? When and how should it be used?
How to conditionally render plain HTML elements like <div>s?
JSTL in JSF2 Facelets... makes sense?
Unrelated to the concrete problem. It's strange to see the conditional rendering depend on localized text. What if you change the locale and/or the localized text? This is very brittle. You'd better check the bundle key instead.
<h:outputText value="#{msg[summary.criticality.key]}" />
<h:panelGroup layout="block" styleClass="alarm1"
rendered="#{summary.criticality.key == 'some.alarm.key'}" />
This way you also don't need to bind the output text anymore.
Try
<c:if test="#{msg[summary.criticality.key].equals('Alarm *')}">
Or add a binding to the h:outputText and check against that.
Try this
<h:outputText id="alarmCriticalityValue" value="#{msg[summary.criticality.key]}" />
<h:panelGroup layout="block" styleClass="alarm1" rendered="#{alarmCriticality.value eq 'Alarm *'}" />
I'm using an <h:outputLink> as follows.
<c:set var="cid" value="1"/>
<c:set var="sid" value="2"/>
<h:outputLink value="Test.jsf">
<h:outputText value="Link"/>
<f:param name="cid" value="#{cid}"/>
<f:param name="sid" value="#{sid}"/>
</h:outputLink>
This is just an example. Both of the query-string parameters are dynamic. So, <c:set> used here is just for the sake of demonstration.
At any time, either one, both or none of the parameters may be present. In case, if only one or none of them is present then, parameter/s are unnecessarily appended to the URL which should not happen. Preventing unnecessary query-string parameters from being appended to the URL requires a conditional rendering of <f:param>.
JSTL <c:if> like the following
<c:if test="${not empty cid}">
<f:param name="cid" value="#{cid}"/>
</c:if>
did not work.
How can it be made possible to conditionally render <f:param> inside <h:outputLink>?
The <f:param> has a disable (not disabled!) attribute for the purpose.
<f:param name="cid" value="#{cid}" disable="#{empty cid}" />
<f:param name="sid" value="#{sid}" disable="#{empty sid}" />
Note that this has a bug in Mojarra versions older than 2.1.15, because they typo'ed the actual UIParameter property to be disble instead of disable. See also issue 2312.
As to the <c:if> approach, that would only work if the #{cid} and #{sid} is available during view build time. In other words, it would fail if they are only available during view render time, e.g. when they depend on var of a repeater component. See also JSTL in JSF2 Facelets... makes sense?
See also:
f:param tag attribute 'disable' is not work
Don't you like this kind of a solution?
<f:param name="#{cid == null ? '' : 'cid'}" value="#{cid}"/>
<f:param name="#{sid == null ? '' : 'sid'}" value="#{sid}"/>
I created a custom JSF tag:
<ui:composition>
<h:panelGroup>
<rich:dataScroller id="#{id}" for="#{table}" execute="#{table}"
page="#{scrollerPage}" render="#{table}-sc1" maxPages="5"
fastControls="hide" oncomplete="#{onCompl}" scrollListener="#{scrollListenerBean[scrollListenerMethod]}" />
<h:inputText value="#{scrollerPage}" id="#{table}-sc1" size="2">
<f:convertNumber integerOnly="true" />
</h:inputText>
<h:outputText styleClass="outputText"
value=" of #{scrollPagesCount} " />
<h:commandButton value="GO! " />
</h:panelGroup>
</ui:composition>
To pass the listener method, I used the solution suggested in a quite old blog:
<my:dataScroller id="idDS1" table="table1"
scrollerPage="#{bean.navigationHelper.scrollerPage}"
scrollPagesCount="#{bean.navigationHelper.scrollPagesCount}"
onCompl="initForm();"
scrollListenerBean="#{bean}"
scrollListenerMethod="aMethod" />
My questions are: is this the best way to do this? How can I make the method optional?
Thanks a lot for any Help! bye!
My questions are: is this the best way to do this?
That's the only way anyway, provided that you can only use standard JSF/EL facilities and you cannot create a custom taghandler.
You could however create a custom taghandler to convert the value expression to a method expression. The OmniFaces JSF utility library has a <o:methodParam> for exactly this purpose. See also the <o:methodParam> demo page.
You could then end up like:
<my:dataScroller ... scrollListener="#{bean.aMethod}" />
and
<o:methodParam name="scrollListenerMethod" value="#{scrollListener}" />
<rich:dataScroller ... scrollListener="#{scrollListenerMethod}" />
See also:
Dynamic ui include and commandButton
How can I make the method optional?
Theoretically, you could use JSTL tags to build the view conditionally. Something like:
<h:someComponent>
<c:if test="#{not empty fooAttribute}">
<f:attribute name="foo" value="#{fooAttriubte}" />
</c:if>
</h:someComponent>
But that's in the particular case of a special method expression listener attribute unfortunately not possible. There's no such thing as <rich:scrollListener> or something which allows you binding a RichFaces specific scrollListener as a separate tag to the <rich:dataScroller>. Best what you could do without creating custom taghandlers is duplicating the whole <rich:dataScroller> in two <c:if>s (or a <c:choose>); one with and other without scrollListener. This is too clumsy. You'd really better create a custom <my:richScrollListener> taghandler for this which you could then place in a <c:if>.
Here is code:
<ui:repeat var="entity" varStatus="status" value="#{myentityListView.someList}">
<h:form>
<h:commandLink value="Go!" action="mypage.xhtml" >
<c:if test="#{entity.entityType=='Comment'}"><f:param name="productId" value="#{entity.product.getId()}"/></c:if>
<f:param name="userId" value="#{entity.user.getId()}"/>
</h:commandLink>
</h:form>
</ui:repeat>
Maybe its cause is that h:commandLink is in ui:repeat.
mypage.xhtml is an exixting page.
Thanks
You need to make sure that #{myentityListView.someList} returns exactly the same value during the form submit request as it was during the request of displaying the page. Putting the bean in the view scope (just mark it #ViewScoped) and ensuring that you preserve the list during (post)constructor or in an action method should fix it.
See also:
commandButton/commandLink/ajax action/listener method not invoked or input value not updated
However, in your particular case, it's much better to just use <h:link> instead as you don't seem to need to send a POST request at all. This way you end up with nice bookmarkable and searchbot-chipherable links.
<ui:repeat var="entity" varStatus="status" value="#{myentityListView.someList}">
<h:form>
<h:link value="Go!" outcome="mypage.xhtml">
<f:param name="userId" value="#{entity.user.id}" />
<f:param name="productId" value="#{entity.product.id}" disable="#{entity.entityType != 'Comment'}" />
</h:link>
</h:form>
</ui:repeat>
Also note that I fixed your <c:if> approach by removing it as it won't work as you'd expect. It would always evaluate false. See also JSTL in JSF2 Facelets... makes sense?
See also:
When should I use h:outputLink instead of h:commandLink?
I have a JSF 2 application with the following code:
<c:set var="number" value="0" scope="view" />
<ui:repeat value="${items}" var="item" varStatus="itemIndex">
<c:if test="${item.boolProperty == true}">
<c:set var="number" value="${number + 1}" scope="view" />
</c:if>
<h:outputText value="#{item.name}" />: <h:outputText value="#{number}" />
</ui:repeat>
I want to increase the number depending on the property of the item in the loop. However, the condition seems not to work, since the value of number always stays 0. If I remove the condition, the number is incremented only once, or it is always 0 before incrementing, therefore it outputs 1. Could it be possible the number var changes not to affect the number var that is outside the loop? I believe the scope attribute takes care of that.
JSTL tags and JSF components doesn't run in sync as you'd expect from the coding. JSTL tags runs during building of the JSF view, while JSF components runs during rendering of the JSF view. See for a detailed explanation also JSTL in JSF2 Facelets... makes sense?
What you want to achieve is unfortunately not possible with JSF components. The <ui:param> comes close, but it functions merely as an alias for a more complex EL expression, while the <c:set> actually sets something in the desired scope (the view scope which you've there is by the way wrong).
Your best bet is to change the model or wrap the model in another model so that you end up as
<ui:repeat value="${items}" var="item" varStatus="itemIndex">
<h:outputText value="#{item.name}" />: <h:outputText value="#{item.number}" />
</ui:repeat>