« Return to Thread: Help with custom tag attribute
Re: Help with custom tag attribute
by Mike Kienenberger
::
Rate this Message:
I'm not certain how you can handle an attribute that might not be
there, but if you know the attribute is always going to be used in
your composition but you don't know if the argument will be specified,
you can use this pattern. Maybe this will help.
<c:if test="${empty rendered}">
<c:set var="rendered" value="${true}" />
</c:if>
<h:panelGroup rendered="#{rendered}">
On Tue, Jul 7, 2009 at 7:42 AM, Felipe Jaekel<fkjaekel@...> wrote:
> Thanks for the help.
>
> I'll try to explain better. My component doesn't have a Java class, its only
> a tag. It looks like this:
>
>> <ui:composition
>> xmlns:h="http://java.sun.com/jsf/html"
>> xmlns:ui="http://java.sun.com/jsf/facelets"
>> >
>> <h:panelGrid
>> columns="2"
>> cellpadding="0"
>> cellspacing="0"
>> >
>> <h:selectBooleanCheckbox
>> id="#{id}"
>> value="#{value}"
>> >
>> <ui:insert />
>> </h:selectBooleanCheckbox>
>> <h:outputLabel
>> value="#{label}"
>> for="#{id}"
>> />
>> </h:panelGrid>
>> </ui:composition>
>
> The id attribute is expecting a value, so every time I use the component I
> have to set it, otherwise I'll get an IllegalArgumentException. If I
> hardcode the id I'll get a duplicated id exception if I have more than 1
> component on the page. If I had a Java class for the component I could
> simply do something like this:
>
>> if(id != null && !id.trim().isEmpty())
>> {
>> component.setId(id);
>> }
>
> How to achieve this on the tag? As I mentioned above f:attribute is not
> working as expected.
>
> Thanks,
> Felipe
>
> 2009/6/19 Fırat KÜÇÜK <firatkucuk@...>
>>
>> Hi,
>> i didn't understand exactly what you mean. But may be this will helps you.
>>
>> this is my jsf managed bean:
>> -----------------------------
>> package mypackage;
>>
>> public class Sample {
>>
>> private String label = "label";
>> private String value = "value";
>> private int id = 0;
>>
>> public Sample() {
>> }
>>
>> public int getId() {
>> return id;
>> }
>>
>> public void setId(int id) {
>> this.id = id;
>> }
>>
>> public String getLabel() {
>> return label;
>> }
>>
>> public void setLabel(String label) {
>> this.label = label;
>> }
>>
>> public String getValue() {
>> return value;
>> }
>>
>> public void setValue(String value) {
>> this.value = value;
>> }
>>
>> public String submit() {
>> label = value;
>> return null;
>> }
>> }
>>
>>
>> --------------------------------------------------
>> and this is facelets file:
>>
>>
>> <?xml version='1.0' encoding='UTF-8' ?>
>>
>> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
>> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
>> <html xmlns="http://www.w3.org/1999/xhtml"
>> xmlns:c="http://java.sun.com/jstl/core"
>> xmlns:f="http://java.sun.com/jsf/core"
>> xmlns:ui="http://java.sun.com/jsf/facelets"
>> xmlns:h="http://java.sun.com/jsf/html">
>> <body>
>> <h:form>
>> <h:outputLabel value="#{sample.label}" />
>> <h:outputLabel value="#{sample.id}" />
>> <h:messages />
>> <h:inputText label="#{sample.label}" value="#{sample.value}">
>> <f:convertNumber />
>> </h:inputText>
>> <h:commandButton value="submit" action="#{sample.submit}">
>> <c:if test="#{!empty sample.id}">
>> <f:setPropertyActionListener target="#{sample.id}"
>> value="#{sample.value}" />
>> </c:if>
>> </h:commandButton>
>> </h:form>
>> </body>
>> </html>
>>
>>
>>
>>
>>
>>
>>
>> 2009/6/19 Felipe Jaekel <fkjaekel@...>
>>>
>>> Actually the problem is that f:attribute is not evaluating the the EL. If
>>> I pass the value literally it accepts, but if I pass #{maxlength} it is
>>> trying to set the string "#{maxlength}" as maxleght, so thats why the I get
>>> the ClassCastException.
>>>
>>>> <h:outputLabel value="#{label}" />
>>>> <h:inputText
>>>> label="#{label}"
>>>> value="#{value}"
>>>> >
>>>> <c:if test="#{! empty id}">
>>>> <f:attribute
>>>> name="id"
>>>> value="#{id}"
>>>> />
>>>> </c:if>
>>>> <ui:insert />
>>>> </h:inputText>
>>>
>>> The id attribute is a better exemple of what I'm trying to do. When it's
>>> not set in the custom tag I'd like that it is not set in the h:inputText tag
>>> so that JSF generates the id. Otherwise always when I use the custom tag
>>> I'll have to set the id or write some crazy workaround to generate it so
>>> that I don't get a duplicated id exception.
>>>
>>> Any ideias? Does f:attribute only accepts literals?
>>>
>>> Thanks,
>>> Felipe
>>>
>>> 2009/5/6 joseph j marini <josephjmarini@...>
>>>>
>>>> Try mapping value to a backing bean #{foo.maxLength}
>>>> in your backing if max length is optional return null, else return
>>>> Integer object with value set. It will get converted automatically.
>>>>
>>>> /Joe
>>>>
>>>>
>>>> --------------------------------------------------
>>>> From: "Zarar Siddiqi" <zarars@...>
>>>> Sent: Wednesday, May 06, 2009 11:26 AM
>>>> To: <users@...>
>>>> Subject: Re: Help with custom tag attribute
>>>>
>>>>> There's a difference between saying something is optional by passing
>>>>> in a null, entirely another to pass in a string and expect it to be
>>>>> ignored just because its not an integer.
>>>>>
>>>>> What is the value of maxlength when you pass it in? Is it null or a
>>>>> string?
>>>>>
>>>>>
>>>>>
>>>>> On Fri, Apr 24, 2009 at 1:16 PM, Felipe Jaekel <fkjaekel@...>
>>>>> wrote:
>>>>>>
>>>>>> I have a custom tag that is composed by a <h:outputLabel /> +
>>>>>> <h:inputText
>>>>>> />. I need the maxlength attribute to be optional. The problem is that
>>>>>> when
>>>>>> I use <f:attribute /> I get a class cast exception.
>>>>>>
>>>>>> Tag:
>>>>>>
>>>>>>> <ui:composition
>>>>>>> xmlns:h="http://java.sun.com/jsf/html"
>>>>>>> xmlns:c="http://java.sun.com/jstl/core"
>>>>>>> xmlns:f="http://java.sun.com/jsf/core"
>>>>>>> xmlns:ui="http://java.sun.com/jsf/facelets"
>>>>>>> >
>>>>>>> <h:outputLabel value="#{label}" />
>>>>>>> <h:inputText
>>>>>>> label="#{label}"
>>>>>>> value="#{value}"
>>>>>>> >
>>>>>>> <c:if test="#{! empty maxlength}">
>>>>>>> <f:attribute
>>>>>>> name="maxlength"
>>>>>>> value="#{maxlength}"
>>>>>>> />
>>>>>>> </c:if>
>>>>>>> <ui:insert />
>>>>>>> </h:inputText>
>>>>>>> </ui:composition>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Exception:
>>>>>>
>>>>>>> java.lang.ClassCastException: java.lang.String cannot be cast to
>>>>>>> java.lang.Integer
>>>>>>
>>>>>>
>>>>>>
>>>>>> Any ideas?
>>>>>>
>>>>>> Thanks,
>>>>>> Felipe
>>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>>> For additional commands, e-mail: users-help@...
>>>>>
>>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>> For additional commands, e-mail: users-help@...
>>>>
>>>
>>
>>
>>
>> --
>> FIRAT KÜÇÜK
>
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscribe@...
For additional commands, e-mail: users-help@...
there, but if you know the attribute is always going to be used in
your composition but you don't know if the argument will be specified,
you can use this pattern. Maybe this will help.
<c:if test="${empty rendered}">
<c:set var="rendered" value="${true}" />
</c:if>
<h:panelGroup rendered="#{rendered}">
On Tue, Jul 7, 2009 at 7:42 AM, Felipe Jaekel<fkjaekel@...> wrote:
> Thanks for the help.
>
> I'll try to explain better. My component doesn't have a Java class, its only
> a tag. It looks like this:
>
>> <ui:composition
>> xmlns:h="http://java.sun.com/jsf/html"
>> xmlns:ui="http://java.sun.com/jsf/facelets"
>> >
>> <h:panelGrid
>> columns="2"
>> cellpadding="0"
>> cellspacing="0"
>> >
>> <h:selectBooleanCheckbox
>> id="#{id}"
>> value="#{value}"
>> >
>> <ui:insert />
>> </h:selectBooleanCheckbox>
>> <h:outputLabel
>> value="#{label}"
>> for="#{id}"
>> />
>> </h:panelGrid>
>> </ui:composition>
>
> The id attribute is expecting a value, so every time I use the component I
> have to set it, otherwise I'll get an IllegalArgumentException. If I
> hardcode the id I'll get a duplicated id exception if I have more than 1
> component on the page. If I had a Java class for the component I could
> simply do something like this:
>
>> if(id != null && !id.trim().isEmpty())
>> {
>> component.setId(id);
>> }
>
> How to achieve this on the tag? As I mentioned above f:attribute is not
> working as expected.
>
> Thanks,
> Felipe
>
> 2009/6/19 Fırat KÜÇÜK <firatkucuk@...>
>>
>> Hi,
>> i didn't understand exactly what you mean. But may be this will helps you.
>>
>> this is my jsf managed bean:
>> -----------------------------
>> package mypackage;
>>
>> public class Sample {
>>
>> private String label = "label";
>> private String value = "value";
>> private int id = 0;
>>
>> public Sample() {
>> }
>>
>> public int getId() {
>> return id;
>> }
>>
>> public void setId(int id) {
>> this.id = id;
>> }
>>
>> public String getLabel() {
>> return label;
>> }
>>
>> public void setLabel(String label) {
>> this.label = label;
>> }
>>
>> public String getValue() {
>> return value;
>> }
>>
>> public void setValue(String value) {
>> this.value = value;
>> }
>>
>> public String submit() {
>> label = value;
>> return null;
>> }
>> }
>>
>>
>> --------------------------------------------------
>> and this is facelets file:
>>
>>
>> <?xml version='1.0' encoding='UTF-8' ?>
>>
>> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
>> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
>> <html xmlns="http://www.w3.org/1999/xhtml"
>> xmlns:c="http://java.sun.com/jstl/core"
>> xmlns:f="http://java.sun.com/jsf/core"
>> xmlns:ui="http://java.sun.com/jsf/facelets"
>> xmlns:h="http://java.sun.com/jsf/html">
>> <body>
>> <h:form>
>> <h:outputLabel value="#{sample.label}" />
>> <h:outputLabel value="#{sample.id}" />
>> <h:messages />
>> <h:inputText label="#{sample.label}" value="#{sample.value}">
>> <f:convertNumber />
>> </h:inputText>
>> <h:commandButton value="submit" action="#{sample.submit}">
>> <c:if test="#{!empty sample.id}">
>> <f:setPropertyActionListener target="#{sample.id}"
>> value="#{sample.value}" />
>> </c:if>
>> </h:commandButton>
>> </h:form>
>> </body>
>> </html>
>>
>>
>>
>>
>>
>>
>>
>> 2009/6/19 Felipe Jaekel <fkjaekel@...>
>>>
>>> Actually the problem is that f:attribute is not evaluating the the EL. If
>>> I pass the value literally it accepts, but if I pass #{maxlength} it is
>>> trying to set the string "#{maxlength}" as maxleght, so thats why the I get
>>> the ClassCastException.
>>>
>>>> <h:outputLabel value="#{label}" />
>>>> <h:inputText
>>>> label="#{label}"
>>>> value="#{value}"
>>>> >
>>>> <c:if test="#{! empty id}">
>>>> <f:attribute
>>>> name="id"
>>>> value="#{id}"
>>>> />
>>>> </c:if>
>>>> <ui:insert />
>>>> </h:inputText>
>>>
>>> The id attribute is a better exemple of what I'm trying to do. When it's
>>> not set in the custom tag I'd like that it is not set in the h:inputText tag
>>> so that JSF generates the id. Otherwise always when I use the custom tag
>>> I'll have to set the id or write some crazy workaround to generate it so
>>> that I don't get a duplicated id exception.
>>>
>>> Any ideias? Does f:attribute only accepts literals?
>>>
>>> Thanks,
>>> Felipe
>>>
>>> 2009/5/6 joseph j marini <josephjmarini@...>
>>>>
>>>> Try mapping value to a backing bean #{foo.maxLength}
>>>> in your backing if max length is optional return null, else return
>>>> Integer object with value set. It will get converted automatically.
>>>>
>>>> /Joe
>>>>
>>>>
>>>> --------------------------------------------------
>>>> From: "Zarar Siddiqi" <zarars@...>
>>>> Sent: Wednesday, May 06, 2009 11:26 AM
>>>> To: <users@...>
>>>> Subject: Re: Help with custom tag attribute
>>>>
>>>>> There's a difference between saying something is optional by passing
>>>>> in a null, entirely another to pass in a string and expect it to be
>>>>> ignored just because its not an integer.
>>>>>
>>>>> What is the value of maxlength when you pass it in? Is it null or a
>>>>> string?
>>>>>
>>>>>
>>>>>
>>>>> On Fri, Apr 24, 2009 at 1:16 PM, Felipe Jaekel <fkjaekel@...>
>>>>> wrote:
>>>>>>
>>>>>> I have a custom tag that is composed by a <h:outputLabel /> +
>>>>>> <h:inputText
>>>>>> />. I need the maxlength attribute to be optional. The problem is that
>>>>>> when
>>>>>> I use <f:attribute /> I get a class cast exception.
>>>>>>
>>>>>> Tag:
>>>>>>
>>>>>>> <ui:composition
>>>>>>> xmlns:h="http://java.sun.com/jsf/html"
>>>>>>> xmlns:c="http://java.sun.com/jstl/core"
>>>>>>> xmlns:f="http://java.sun.com/jsf/core"
>>>>>>> xmlns:ui="http://java.sun.com/jsf/facelets"
>>>>>>> >
>>>>>>> <h:outputLabel value="#{label}" />
>>>>>>> <h:inputText
>>>>>>> label="#{label}"
>>>>>>> value="#{value}"
>>>>>>> >
>>>>>>> <c:if test="#{! empty maxlength}">
>>>>>>> <f:attribute
>>>>>>> name="maxlength"
>>>>>>> value="#{maxlength}"
>>>>>>> />
>>>>>>> </c:if>
>>>>>>> <ui:insert />
>>>>>>> </h:inputText>
>>>>>>> </ui:composition>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>> Exception:
>>>>>>
>>>>>>> java.lang.ClassCastException: java.lang.String cannot be cast to
>>>>>>> java.lang.Integer
>>>>>>
>>>>>>
>>>>>>
>>>>>> Any ideas?
>>>>>>
>>>>>> Thanks,
>>>>>> Felipe
>>>>>>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>>> For additional commands, e-mail: users-help@...
>>>>>
>>>>>
>>>>
>>>> ---------------------------------------------------------------------
>>>> To unsubscribe, e-mail: users-unsubscribe@...
>>>> For additional commands, e-mail: users-help@...
>>>>
>>>
>>
>>
>>
>> --
>> FIRAT KÜÇÜK
>
>
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To unsubscribe, e-mail: users-unsubscribe@...
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