Conditionally render element's attribute in a composite component

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?

Please be careful with tagging, a composite component is not a custom component. See also http://stackoverflow.com/questions/5704620/what-is-the-difference-between-custom-components-and-composite-components — BalusC, Oct 15 '12 at 14:18
Thanks for the correction. I'm aware of that but I was a bit careless, maybe I need a couple of minutes break :S — Balázs Németh, Oct 15 '12 at 14:27

score 13 · Accepted Answer · answered Oct 15 '12 at 14:17

13

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" />

answered Oct 15 '12 at 14:17

BalusC

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Thank you! It works but it's strange for me that if I add directly `` or `` I get `javax.servlet.ServletException: argument type mismatch` and if I add `` I get `Open quote is expected for attribute "value"`. – Balázs Németh Oct 15 '12 at 14:35
It has to be an `Integer`, not `String`. – BalusC Oct 15 '12 at 14:39
Yes, but how to add an `Integer` in the `value` attribute? With quotes it is interpreted as `String`, without quotes the exception is different. – Balázs Németh Oct 15 '12 at 14:42

Jens Bernert · Answer 2 · 2013-03-04T08:37:13.100

2

Additional to BalusC's post:

You must use

type="int" in the cc:attribute-tag :

cc:attribute name="maxlength" type="int"

edited Mar 04 '13 at 08:37

answered Mar 01 '13 at 15:25

Jens Bernert

21
3

score 0 · Answer 3 · edited Jun 20 '20 at 09:12

0

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']}

edited Jun 20 '20 at 09:12

Community

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1

answered Nov 08 '13 at 16:35

Revoman

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6

Conditionally render element's attribute in a composite component

3 Answers3

{cc.attrs['size']}

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