"Fake" Dynamic Field to Form [using rendered]

[Marco Noronha]

Hi guys...

I want to do the following:

A select one menu with fields names.
A button to add the field to the form.

BUT! The field is already there! But it was been "rendered" false to start with.
So, my idea is: when the user clicks on the add button, the method that handles the rendered boolean for each field
will then return TRUE, and the ajax update":form" should do the trick and make the field appear.
But didn´t work.

The front end with the select one menu.

        <h:form id="filterForm">
	<p:panelGrid columns="6" style="margin: 0px auto;">
        	<f:facet name="header">

       <p:selectOneMenu value="#{grupoController.selectedFilter}">  
            <f:selectItem itemLabel="Selecione um filtro..." itemValue="" />  
            <f:selectItem itemLabel="Idade" itemValue="filterIdade" />  
            <f:selectItem itemLabel="Data" itemValue="filterData" />  
            <f:selectItem itemLabel="Descricao/Unidade" itemValue="filterUnidadeDesc" />  
        </p:selectOneMenu>  
        <p:commandButton icon="ui-icon-circle-plus" actionListener="#{grupoController.givePermission()}" update=":filterForm"/>
        
          
        	</f:facet>
		
			<!-- ID -->
        	<p:outputLabel for="filterId" value="#{msg['entity.codigo']}"/>
			<p:inputText id="filterId" value="#{grupoController.entityFilter.id}"/>

        	<p:outputLabel for="filterIdOperation" value="#{msg['label.operation']}"/>
			<p:selectOneMenu id="filterIdOperation" converter="queryOperationConverter" value="#{grupoController.entityFilter.idOperation}" >
				<f:selectItems value="#{grupoController.queryOperationAsArray}" />
			</p:selectOneMenu>

        	<p:outputLabel for="filterIdMatch" value="#{msg['label.match']}"/>
			<p:selectOneMenu id="filterIdMatch" converter="matchModeConverter" value="#{grupoController.entityFilter.idMatch}" >
				<f:selectItems value="#{grupoController.matchModeAsArray}" />
			</p:selectOneMenu>

			<!-- Descricao -->			
			<p:outputLabel for="filterDesc" value="#{msg['entity.descricao']}"/>
			<p:inputText id="filterDesc" value="#{grupoController.entityFilter.descricao}"/>

        	<p:outputLabel for="filterDescOperation" value="#{msg['label.operation']}"/>
			<p:selectOneMenu id="filterDescOperation" converter="queryOperationConverter" value="#{grupoController.entityFilter.descOperation}" >
				<f:selectItems value="#{grupoController.queryOperationAllAsArray}" />
			</p:selectOneMenu>

        	<p:outputLabel for="filterDescMatch" value="#{msg['label.match']}"/>
			<p:selectOneMenu id="filterDescMatch" converter="matchModeConverter" value="#{grupoController.entityFilter.descMatch}" >
				<f:selectItems value="#{grupoController.matchModeAsArray}" />
			</p:selectOneMenu>

			<!-- Idade -->
			<p:outputLabel rendered="#{grupoController.filterIsVisible(filterIdade)}" for="filterIdade" value="#{msg['entity.idade']}"/>
			<p:inputText rendered="#{grupoController.filterIsVisible(filterIdade)}" id="filterIdade" value="#{grupoController.entityFilter.idade}"/>

        	<p:outputLabel rendered="#{grupoController.filterIsVisible(filterIdade)}" for="filterIdadeOperation" value="#{msg['label.operation']}"/>
			<p:selectOneMenu rendered="#{grupoController.filterIsVisible(filterIdade)}" id="filterIdadeOperation" converter="queryOperationConverter" value="#{grupoController.entityFilter.idadeOperation}" >
				<f:selectItems value="#{grupoController.queryOperationAsArray}" />
			</p:selectOneMenu>

        	<p:outputLabel rendered="#{grupoController.filterIsVisible(filterIdade)}" for="filterIdadeMatch" value="#{msg['label.match']}"/>
			<p:selectOneMenu rendered="#{grupoController.filterIsVisible(filterIdade)}" id="filterIdadeMatch" converter="matchModeConverter" value="#{grupoController.entityFilter.idadeMatch}" >
				<f:selectItems value="#{grupoController.matchModeAsArray}" />
			</p:selectOneMenu>

Some fields are by default VISIBLE, so no rendered needed.

the methods on managedBean:

public void givePermission(){
    	filtersMap.put(selectedFilter, Boolean.TRUE);
    }
    
    public void forbidPermission(){
    	filtersMap.put(selectedFilter, Boolean.FALSE);
    }

    public Boolean filterIsVisible(String filter){
    	Boolean value = filtersMap.get(filter); 
    	return ObjectUtil.naoNulos(value) ? value : false;
    }

As you can see, I have an HASHMAP to control if that field is visible or not.

Did I do something wrong on the front end?

[Tim Holloway]

#{grupoController.filterIsVisible(filterIdade)}

Is not good practice. You should not be coding parameters on the View if at all possible. Also, I'm not even sure that you can do a general method call in the context of a "rendered" attribute to begin with, Normally you should be making a property reference.

I also cannot make sense of what appears to be a possible page-scope variable "filterIdade". JSF does not support page scope at all. To function properly, "filterIdade" needs to be a property of a backing bean, not an independent entity.

[Marco Noronha]

Tim Holloway wrote:

#{grupoController.filterIsVisible(filterIdade)}

Is not good practice. You should not be coding parameters on the View if at all possible. Also, I'm not even sure that you can do a general method call in the context of a "rendered" attribute to begin with, Normally you should be making a property reference.

I also cannot make sense of what appears to be a possible page-scope variable "filterIdade". JSF does not support page scope at all. To function properly, "filterIdade" needs to be a property of a backing bean, not an independent entity.

thanks for the answer.
Well... I got it running Tim.

You right about the bad pratices. But it works.
Maybe it should be an convencion for my project.

The correct xhtml looks like this:

			<p:outputLabel rendered="#{grupoController.filterIsVisible('grupo.idade')}" for="grupoIdade" value="#{msg['entity.idade']}"/>
			<p:inputText rendered="#{grupoController.filterIsVisible('grupo.idade')}" id="grupoIdade" value="#{grupoController.entityFilter.idade}"/>

[Tim Holloway]

"It works" isn't a happy phrase for me. It's often followed by "it broke". And "I haven't the faintest idea of how this ever worked". Or "We can't change that".

Here's a more JSF-friendly expression:

"#{grupoController.filterIsVisible['grupo.idade']}"

Note that I've changed "filterIsVisible" to a property referencing a Map<String, Boolean>, and made "grupo.idade" be a key into the map.

And, BTW. Backing beans are NOT Controllers. In JSF the Controllers are pre-supplied in the FacesServlet and in the tag internal implementations. Backing beans are Models. Listeners and Action methods are not Controller methods. Action methods, in fact, are business logic.

[Marco Noronha]

Tim Holloway wrote:

"#{grupoController.filterIsVisible['grupo.idade']}"

Wow! That was very very good!
But I need a method on the backing bean because I use it on the java side as well.

Oh, I thought ManagedBean would be like an controller...
Basiclly i dont have a controller. Only Model and View on JSF

[Tim Holloway]

The backing bean method is:

/**
 * Fetch Map property
 * @return Map
*/
public Map<String, Boolean> getFilterIsVisible() {
   return this.filterIsVisible;
}

So the Java usage would be:

  Boolean showMe = getFilterIsVisible().get('grupo.idade');

However, "magic" values are not considered ideal even in pure Java code, much less on View Definitions, so it might be better to do this:

/**
 * Read-only property to test for grupo idade visibility
 * @return <code>true</code> to show grupo idade.
*/
public boolean isShowGrupoIdade() {
   Boolean showMe = getFilterIsVisible().get('grupo.idade');
   return showMe;
}

You would then be a able to invoke that method directly in Java code and you would also be able to simplify your View Template:

            <p:outputLabel rendered="#{grupoController.showGrupoIdade}" for="grupoIdade" value="#{msg['entity.idade']}"/>  
            <p:inputText rendered="#{grupoController.showGrupoIdade}" id="grupoIdade" value="#{grupoController.entityFilter.idade}"/>  

It's always desirable to keep the EL as simple as possible. Even if you don't subscribe to the the "No Logic In View Rule", debugging EL is a

In JSF, you do have Controllers. The difference is, you don't code them yourself (usually!). Most of the Controllers you need are already supplied.

[Marco Noronha]

I understand.
But if I have a view with 50 fields ?

Wouldn´t be too 'manual' writing one method per field?

[Tim Holloway]

Marco Noronha wrote:I understand.
But if I have a view with 50 fields ?

Wouldn´t be too 'manual' writing one method per field?

Probably. Then again, I think I probably would have used a dataTable for the display with a List or array model, and that would have allowed me to simply use indexing instead of complicated Map expressions.

[Marco Noronha]

Tim Holloway wrote:

Marco Noronha wrote:I understand.
But if I have a view with 50 fields ?

Wouldn´t be too 'manual' writing one method per field?

Probably. Then again, I think I probably would have used a dataTable for the display with a List or array model, and that would have allowed me to simply use indexing instead of complicated Map expressions.

can you please show me an example of that working?

[Tim Holloway]

I recommend looking at a good JSF book.

[Marco Noronha]

Tim Holloway wrote:I recommend looking at a good JSF book.

I read the Core JavaServer Faces Ed. 3.

Any other recomendations?


IT would be really nice of you, if you could
just show me am example
but I don´t want to make you lose your time..

So thanks anyway