This is called 3 times, for each row once. (example table has 3 rows)
....
<ui:param name="rowIndex" value="#{cc.attrs.rowIndex}" />
<ui:param name="rowActive" value="#{cc.attrs.activeRow}" />
<c:set var="index" value="#{rowIndex}" type="java.lang.Long"/>
<c:set var="activeRowIndex" value="#{rowActive}" type="java.lang.Long"/>
<c:choose>
<c:when test="${index == 2}">
ACTIVE
</c:when>
<c:when test="${index != activeRowIndex}">
${index} - ${activeRowIndex} - INACTIVE
</c:when>
<c:otherwise>
NONE
</c:otherwise>
</c:choose>
....
Result:
0 - 1 - INACTIVE
1 - 1 - INACTIVE
2 - 1 - INACTIVE
I would have expected:
0 - 1 - INACTIVE
NONE
ACTIVE
I'm quite clueless why the result is so different from what i expected.
So i hope you can help me :-)
The variable names used suggests that you're using the composite inside a repeating component, such as <h:dataTable> or <ui:repeat>.
JSTL tags are executed during view build time, that moment when the JSF component tree is built based on XHTML source code. However, the var attribute of a repeating component is only available during view render time, that moment when the HTML output is produced based on JSF component tree.
In effects, at least the #{cc.attrs.rowIndex} is always null when JSTL runs.
When you're dependent on conditions which are only available during view render time, then you should be using the rendered attribute of a JSF component instead of JSTL <c:choose>/<c:if>.
E.g.
<c:set var="active" value="#{cc.attrs.rowIndex == 2}" />
<c:set var="inactive" value="#{not active and cc.attrs.rowIndex != cc.attrs.activeRow}" />
<c:set var="none" value="#{not active and not inactive}" />
<h:outputText value="ACTIVE" rendered="#{active}" />
<h:outputText value="#{index} - #{activeRowIndex} - INACTIVE" rendered="#{inactive}" />
<h:outputText value="NONE" rendered="#{none}" />
Note that this problem doesn't affect the <c:set>. It merely creates a EL variable mapping (an "alias"), it doesn't immediately evaluate the EL expression and store its result somewhere (as long as scope isn't definied). Also note that ${} and #{} behave exactly the same when Facelets is used instead of JSP. As the ${} is basically a heritage of legacy JSP, you should prefer exclusively using #{} to avoid confusion by yourself and your future maintainers.
Related
I am using templating and pass some values by to use them in the template:
<ui:repeat var="entry" value="#{showEntriesBean.entries}" id="repeatId">
<ui:include src="/templates/entryTemplate.xhtml">
<ui:param name="prePath" value="/" />
<ui:param name="allowedToSee" value="#{bean.calcRandom(0, 10)}" />
</ui:include>
<br />
</ui:repeat>
I found out, that everytime I use the "allowedToSee" variable in my entryTemplate.xhtml, it recalculates its value.
Is there any way to pass the result of calcRandom in a static way? So it is ONCE calculated (when the allowedToSee value is calculated) and performs like a final number? I don't want it to be calculated everytime #{allowedToSee} is used
If you want the value to be held, you should held it somewhere.
What I would do:
1) Create a List<Integer> property.
2) When the values of the entries properties are set, call a method (preRenderEvent? #PostConstruct?) that introduces in your list as many items as there are in entries.
3) Consult that list using the varStatus attribute of ui:repeat
Little more of less, like:
<ui:repeat var="entry" value="#{showEntriesBean.entries}" id="repeatId" varStatus="status">
<ui:include src="/templates/entryTemplate.xhtml">
<ui:param name="prePath" value="/" />
<ui:param name="allowedToSee" value="#{bean.getPrecalculedRandomAt(status.index)}" />
</ui:include>
<br />
</ui:repeat>
More on the varStatus attribute: http://docs.oracle.com/javaee/6/javaserverfaces/2.0/docs/pdldocs/facelets/ui/repeat.html
I have searched and tried but this time I'm really stuck.
I am trying to build a simple datatable (primefaces) where the cell content can be of different types. There is a holder class for each cell content that can hold different entities and I want to use < c:choose> to check and display the right entity in the entity specific way.
The code looks like:
<p:dataTable emptyMessage="" value="#{date.getThreadContent(column.propertyID)}" var="content">
<p:column>
#{content.type}
<c:choose>
<c:when test="#{content.type == 'activity'}">
#{content.activity.name}
</c:when>
<c:when test="#{content.type == 'todo'}">
#{content.activity.name}
</c:when>
<c:otherwise>
Neither activity or todo
</c:otherwise>
</c:choose>
</p:column>
</p:dataTable>
The EL evaluation doesn't work regardless if I try a boolean or String values in the bean (I'm using String value in the code above).
So each time the content is not empty, the output first displays the correct content type from #{content.type} but then together with 'Neither activity or todo'.
I can also say that this data table itself represents a cell content in a parent data table (list of entities per date) that is not visible in this code as I try to isolate the problem.
Could it be that this type of expression cannot be done in a ?
Any help is appreciated.
Use JSF rendered tags to do your conditional display logic, it removes it from the DOM completely and makes validations easier.
Refer: http://docs.oracle.com/javaee/6/tutorial/doc/bnaik.html for EL expressions
Also a good explanation is provided by BalusC here: JSTL c:if doesn't work inside a JSF h:dataTable
<p:dataTable emptyMessage="" value="#{date.getThreadContent(column.propertyID)}" var="content">
<p:column>
#{content.type}
<h:outputText value="#{content.activity.name}" rendered="#{content.type == 'activity' or content.type == 'todo'}" />
<h:outputText value="Neither activity or todo" rendered="#{content.type != 'activity' and content.type != 'todo'}" />
</p:column>
</p:dataTable>
If i have this code on my jsf page:
<c:choose>
<c:when test="${empty example1}">
</c:when>
<c:when test="${empty example2}">
</c:when>
<c:otherwise>
</c:otherwise>
</c:choose>
it will work like java switch statement with case and break - if first when is true, second won't be test, right ?
What should i write to get "switch statement with case but without break" :
when first C:when is true something add to page and when second is true something is add to page too
You're thus basically looking for a fall-through switch. That isn't possible with <c:choose> as it represents a true if-else.... JSTL does not offer any tags for a fall-through switch.
Your best bet is to use multiple <c:if>s wherein you also check the preceding condition as an or condition.
<c:if test="#{empty example1}">
...
</c:if>
<c:if test="#{empty example1 or empty example2}">
...
</c:if>
<c:if test="#{empty example1 or empty example2 or empty example3}">
...
</c:if>
...
As you're using JSF, an alternative is using component's rendered attribute.
<h:panelGroup rendered="#{empty example1}">
...
</h:panelGroup>
<h:panelGroup rendered="#{empty example1 or empty example2}">
...
</h:panelGroup>
<h:panelGroup rendered="#{empty example1 or empty example2 or empty example3}">
...
</h:panelGroup>
...
The difference is that it's evaluated during view render time instead of during view build time. So if you were for example using this inside a <h:dataTable> based on the currently iterated row, the <c:if> wouldn't have worked the way you'd expect. See also JSTL in JSF2 Facelets... makes sense?
To eliminate the condition checking boilerplate, you could use <c:set> to create new EL variables. This works in both approaches.
<c:set var="show1" value="#{empty example1}" />
<c:set var="show2" value="#{show1 or empty example2}" />
<c:set var="show3" value="#{show2 or empty example3}" />
<h:panelGroup rendered="#{show1}">
...
</h:panelGroup>
<h:panelGroup rendered="#{show2}">
...
</h:panelGroup>
<h:panelGroup rendered="#{show3}">
...
</h:panelGroup>
...
I think it isn't possible with c:when. You can use c:if instead:
<c:if test="${empty example1}">
"example1 empty"
</c:if>
<c:if test="${empty example2}">
"example2 empty"
</c:if>
<c:if test="${not empty example1 and not empty example2}">
"both not empty"
</c:if>
How do I show JSF components if a list is not null and it has a size() > 0?
EL offers the empty operator which checks both the nullness and emptiness of an object.
Thus, this should do:
<h:dataTable value="#{bean.list}" var="item" rendered="#{not empty bean.list}">
No need for a clumsy double check on both null and size() as suggested by other answers.
See also:
How do I display a message if a jsf datatable is empty?
Conditionally displaying JSF components
use rendered attribute. most of the components have this attribute.This attribute;s main purpose is to render components conditionally.
<h:dataTable value="#{bean.list}" rendered="{bean.list !=null && bean.list.size()>0}" >
In the above piece of jsf code, datatable would only be rendered when list is not null and the size of list is greater than 0
<h:outputText value="No Data to Display!" rendered="#{empty list1.List2}" />
<a href="#">
<h:outputText value="Data is present" rendered="#{not empty list1.List2}" /></a>
Or
<h:outputText value="#{not empty list1.List2 ? 'Data is Present' : 'No Data to Display'}" style="color:blue"/>
I am trying to render richfaces and jsf UI elements dynamically based on the dataType value.
Ex : I have a enum as below
public enum DataType {
DT_LONGLONG(1), DT_STRING(2), DT_LONG(3), DT_DATE(4), DS_EXTERNALREFERENCE(5),
DT_BOOLEAN(6), DT_FLOAT(7), DT_SHORT(8);
}
Then in xhtml page while iterating through the list of my custom objects, I check for the dataType and render the UI elements accordingly as below :
<c:if test="#{meaCompPartAttr.dataType.dataType == 2}">
<h:inputText />
</c:if>
<c:if test="#{(meaCompPartAttr.dataType.dataType == 1) or
(meaCompPartAttr.dataType.dataType == 3) or
(meaCompPartAttr.dataType.dataType == 8)}">
<h:inputText onkeyup="javascript:validateField(this, '#{tpMsgs.longRegularExpression}');">
<f:validateLongRange/>
</h:inputText>
</c:if>
<c:if test="#{meaCompPartAttr.dataType.dataType == 7}">
<h:inputText onkeyup="javascript:validateField(this, '#{tpMsgs.doubleRegularExpression}');">
<f:validateDoubleRange/>
</h:inputText>
</c:if>
<c:if test="#{meaCompPartAttr.dataType.dataType == 6}">
<h:selectBooleanCheckbox />
</c:if>
<c:if test="#{meaCompPartAttr.dataType.dataType == 4}">
<rich:calendar />
</c:if>
Because of this I usually get class cast exceptions like String to Boolean or Long to String etc. I assume this is happening coz jstl and jsf code do not run in sync.
Is there any other approach to render UI elements dynamically as proposed in the above sample?
So you're iterating using <ui:repeat> or <h:dataTable> or any other JSF iterating component instead of the JSTL <c:forEach>? Either use <c:forEach> instead, or use the rendered attribute instead of <c:if>.
See also:
JSTL in JSF2 Facelets... makes sense?
How to create dynamic JSF form fields