Conditionally render element's attribute in a composite component - jsf

Question

I have the following composite component:
<?xml version="1.0" encoding="UTF-8"?>
<ui:component xmlns="http://www.w3.org/1999/xhtml"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:c="http://java.sun.com/jsp/jstl/core"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:p="http://primefaces.org/ui"
xmlns:fn="http://java.sun.com/jsp/jstl/functions"
xmlns:composite="http://java.sun.com/jsf/composite">
<composite:interface>
<composite:attribute required="true" name="field" />
<composite:attribute required="true" name="value" />
<composite:attribute required="false" name="size"/>
</composite:interface>
<composite:implementation>
...
<div class="wrapper">
<h:inputText value="#{cc.attrs.value}"
id="#{field.id}"
rendered="#{field.rendered}"
size="#{cc.attrs.size}">
</h:inputText>
<h:messages for="#{field.id}" styleClass="errorMessage"/>
</div>
...
</composite:implementation>
</ui:component>
The problem is that when I'm using this component without setting its size attribute, it still gets rendered as size=0 in the html input element.
What I want is to render the nested h:inputText's attribute only if it has a valid value (eg. not empty). Alternatively, I'd like to expose all attributes of the nested element if they are not overridden explicitly.
How would it be possible?

Answer 1

You can use JSTL <c:if> to build the view conditionally and <f:attribute> to specify an attribute separately:
<h:inputText ...>
<c:if test="#{not empty cc.attrs.size}">
<f:attribute name="size" value="#{cc.attrs.size}" />
</c:if>
</h:inputText>
An alternative is to specify a default for the composite component attribute:
<cc:attribute name="size" required="false" default="10" />

Answer 2

Additional to BalusC's post:
You must use
type="int" in the cc:attribute-tag :
cc:attribute name="maxlength" type="int"

Answer 3

I believe there is an alternate method for accessing attributes. I've used this with JSF 2 when accessing an attribute named with a java reserved keyword.
{cc.attrs['size']}