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Posted to users@myfaces.apache.org by mjovanov <mi...@jpmchase.com> on 2008/05/01 18:20:44 UTC
Re: Duplicate id in faces tree error - removing JSTL?
simon.kitching@chello.at wrote:
>
>
> On Mon, 2008-04-28 at 08:46 -0700, mjovanov wrote:
>> After upgrading to MyFaces 1.2.2 I am getting a “duplicate id in the
>> faces
>> tree” error. I have isolated it to the following section of code:
>>
>> <t:column id="${fieldName}" styleClass="${columnStyleClass}"
>> rendered="${renderValue}">
>>
>> <f:facet name="header">
>> <t:commandSortHeader columnName="${fieldName}" arrow="true"
>> actionListener="#{backingBean.sortChanged}"
>> immediate="true"
>> styleClass="cellDataHeader">
>> ${label}
>> </t:commandSortHeader>
>> </f:facet>
>>
>> <c:choose>
>> ...
>> ...
>> <c:when test="${empty secondaryFieldName}">
>>
>> <c:if test="${not empty linkAction}">
>> <h:commandLink action="#{backingBean.details}" immediate="true">
>> <c:choose>
>> <c:when test="${not empty dateFormat}">
>> <h:outputText value="${entity[fieldName]}">
>> <f:convertDateTime type="date" timeZone="${timeZone}"
>> dateStyle="${dateFormat}"
>> pattern="${datePattern}" />
>> </h:outputText>
>> </c:when>
>>
>> <c:when test="${not empty currencyPattern}">
>> <h:outputText value="${entity[fieldName]}">
>> <f:convertNumber pattern="${currencyPattern}" />
>> </h:outputText>
>> <br />
>> </c:when>
>>
>> <c:otherwise>
>> <h:outputText value="${entity[fieldName]}" />
>> </c:otherwise>
>> </c:choose>
>>
>> <f:param name="itemType" value="${linkAction}" />
>> <f:param name="fieldName" value="${fieldName}" />
>> <f:param name="addParam" value="${addParam}" />
>> </h:commandLink>
>>
>> The sections marked in bold indicate the components for which duplicate
>> ids
>> are being generated. I should also mention we are using facelets +
>> xhtml,
>> and the code listed above is in a facelet that is being invoked from the
>> main page.
>>
>> Reading some previous posts is seems the problem is most likely caused by
>> mixing JSTL and JSF tags; ideally I would want to remove the JSTL tags,
>> but
>> the facelet in question was not written by me and is quite long so I
>> would
>> only want to do this as a last resort.
>>
>> My question is: can anyone suggest an alternative solution to rewriting
>> the
>> facelet without JSTL tags? I realize I could also solve this issue by
>> explicitly naming the components but would like to understand better how
>> the
>> auto id generation works in MyFaces.
>>
>> Also, if the only "right" solution is to remove the JSTL tags, can
>> someone
>> suggest how to do this, considering they appear to be used extensively
>> (c:if, c:when…)?
>
> The only right solution is to remove the JSTL tags.
>
> Conditional tags are dangerous with any JSF component. And they are
> totally incompatible with JSF looping components like tables; this
> applies to JSF1.1 too.
>
> JSF is fundamentally a two-pass system (build component tree, then
> render component tree). This was only partially true in JSF1.1, but is
> completely true in JSF1.2. But JSTL is a one-pass system, and so
> conditional statements interacts very badly with JSF components that
> have significant behaviour in the second pass.
>
> I suggest that where a c:when or c:if wraps just one JSF component, then
> move the condition into a "rendered" attribute on that component. When
> it wraps more than one, then replace the JSTL tag with an h:panelGroup
> or t:div, and move the condition into the rendered attribute of that new
> tag. In most cases, that will do the trick.
>
> Note that JSTL *can* be used with JSF in some cases, but you really need
> to re-read and understand both the JSP specification bits about how tags
> work, and the JSF specification bits about the JSF lifecycle. So in
> general, it's best to avoid mixing them.
>
> Regards,
> Simon
>
>
>
Hi Simon, thanks again for your quick response. We did go ahead and removed
the JSTL tags, but were surprised to find that did not take care of the
problem. So, after gradually removing parts of the code, I was able to
pinpoint it to our use of the Facelets. I tried upgrading from Facelets
1.1.11 to 1.1.14 and, sure enough, that took care of it! Just wanted to
follow up, in case someone else experiences a similar issue.
Searching through forum posts, it seems like this is a well-known issue
related to incompatibility between particular versions of facelets and My
Faces; are you aware on the latest on this, particularly as it relates to
the "duplicate id in Faces tree" issue?
Mihajlo
--
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Re: Duplicate id in faces tree error - removing JSTL?
Posted by simon <si...@chello.at>.
Ah, that explains it. Thanks Andrew.
mjovanov: after JSF has rendered a page, it saves the state of
"important" components in the tree (those that are not "transient").
When a "postback" occurs, it restores the component tree from
information it saved at the end of the previous render phase. That
information is enough to handle the postback. But if the same view needs
to be re-rendered, then JSF needs to reprocess the original page (.jsp
or .xhtml file) to rebuild those transient components. But in order to
match up tags in a page with existing objects in the restored component
tree, JSF has to do a kind of "dead reckoning"
(http://en.wikipedia.org/wiki/Dead_reckoning).
When components have explicit ids, that makes it easier to match them
up. But otherwise it requires careful tracking of the "current
position". That's why tags that change the "component tree shape" (such
as c:if) are not generally a good idea with JSF, and why using the
"rendered" flag to control components is better.
Regards,
Simon
On Fri, 2008-05-02 at 13:38 -0600, Andrew Robinson wrote:
> Facelets implements partial support of JSTL. Jacob created TagHandlers
> for the "popular" JSTL tags (if, choose, when, forEach). The tags
> handlers reproduce the JSP behavior and have the same caveats of the
> JSTL tags (run during component creation, not evaluation). In general,
> you cannot use JSP tags in facelets. You only can if you create a
> TagHandler that mimics the behavior and register it using the same
> namespace to "fool" users to think that it is working out of the box.
>
> -Andrew
>
> On Fri, May 2, 2008 at 1:29 PM, simon <si...@chello.at> wrote:
> >
> >
> > On Thu, 2008-05-01 at 09:20 -0700, mjovanov wrote:
> > >
> > > simon.kitching@chello.at wrote:
> > > >
> > > >
> > > > On Mon, 2008-04-28 at 08:46 -0700, mjovanov wrote:
> > > >> After upgrading to MyFaces 1.2.2 I am getting a "duplicate id in the
> > > >> faces
> > > >> tree" error. I have isolated it to the following section of code:
> > > >>
> > > >> <t:column id="${fieldName}" styleClass="${columnStyleClass}"
> > > >> rendered="${renderValue}">
> > > >>
> > > >> <f:facet name="header">
> > > >> <t:commandSortHeader columnName="${fieldName}" arrow="true"
> > > >> actionListener="#{backingBean.sortChanged}"
> > > >> immediate="true"
> > > >> styleClass="cellDataHeader">
> > > >> ${label}
> > > >> </t:commandSortHeader>
> > > >> </f:facet>
> > > >>
> > > >> <c:choose>
> > > >> ...
> > > >> ...
> > > >> <c:when test="${empty secondaryFieldName}">
> > > >>
> > > >> <c:if test="${not empty linkAction}">
> > > >> <h:commandLink action="#{backingBean.details}" immediate="true">
> > > >> <c:choose>
> > > >> <c:when test="${not empty dateFormat}">
> > > >> <h:outputText value="${entity[fieldName]}">
> > > >> <f:convertDateTime type="date" timeZone="${timeZone}"
> > > >> dateStyle="${dateFormat}"
> > > >> pattern="${datePattern}" />
> > > >> </h:outputText>
> > > >> </c:when>
> > > >>
> > > >> <c:when test="${not empty currencyPattern}">
> > > >> <h:outputText value="${entity[fieldName]}">
> > > >> <f:convertNumber pattern="${currencyPattern}" />
> > > >> </h:outputText>
> > > >> <br />
> > > >> </c:when>
> > > >>
> > > >> <c:otherwise>
> > > >> <h:outputText value="${entity[fieldName]}" />
> > > >> </c:otherwise>
> > > >> </c:choose>
> > > >>
> > > >> <f:param name="itemType" value="${linkAction}" />
> > > >> <f:param name="fieldName" value="${fieldName}" />
> > > >> <f:param name="addParam" value="${addParam}" />
> > > >> </h:commandLink>
> > > >>
> > > >> The sections marked in bold indicate the components for which duplicate
> > > >> ids
> > > >> are being generated. I should also mention we are using facelets +
> > > >> xhtml,
> > > >> and the code listed above is in a facelet that is being invoked from the
> > > >> main page.
> > > >>
> > > >> Reading some previous posts is seems the problem is most likely caused by
> > > >> mixing JSTL and JSF tags; ideally I would want to remove the JSTL tags,
> > > >> but
> > > >> the facelet in question was not written by me and is quite long so I
> > > >> would
> > > >> only want to do this as a last resort.
> > > >>
> > > >> My question is: can anyone suggest an alternative solution to rewriting
> > > >> the
> > > >> facelet without JSTL tags? I realize I could also solve this issue by
> > > >> explicitly naming the components but would like to understand better how
> > > >> the
> > > >> auto id generation works in MyFaces.
> > > >>
> > > >> Also, if the only "right" solution is to remove the JSTL tags, can
> > > >> someone
> > > >> suggest how to do this, considering they appear to be used extensively
> > > >> (c:if, c:when…)?
> > > >
> > > > The only right solution is to remove the JSTL tags.
> > > >
> > > > Conditional tags are dangerous with any JSF component. And they are
> > > > totally incompatible with JSF looping components like tables; this
> > > > applies to JSF1.1 too.
> > > >
> > > > JSF is fundamentally a two-pass system (build component tree, then
> > > > render component tree). This was only partially true in JSF1.1, but is
> > > > completely true in JSF1.2. But JSTL is a one-pass system, and so
> > > > conditional statements interacts very badly with JSF components that
> > > > have significant behaviour in the second pass.
> > > >
> > > > I suggest that where a c:when or c:if wraps just one JSF component, then
> > > > move the condition into a "rendered" attribute on that component. When
> > > > it wraps more than one, then replace the JSTL tag with an h:panelGroup
> > > > or t:div, and move the condition into the rendered attribute of that new
> > > > tag. In most cases, that will do the trick.
> > > >
> > > > Note that JSTL *can* be used with JSF in some cases, but you really need
> > > > to re-read and understand both the JSP specification bits about how tags
> > > > work, and the JSF specification bits about the JSF lifecycle. So in
> > > > general, it's best to avoid mixing them.
> > > >
> > > > Regards,
> > > > Simon
> > > >
> > > >
> > > >
> > >
> > > Hi Simon, thanks again for your quick response. We did go ahead and removed
> > > the JSTL tags, but were surprised to find that did not take care of the
> > > problem. So, after gradually removing parts of the code, I was able to
> > > pinpoint it to our use of the Facelets. I tried upgrading from Facelets
> > > 1.1.11 to 1.1.14 and, sure enough, that took care of it! Just wanted to
> > > follow up, in case someone else experiences a similar issue.
> > >
> > > Searching through forum posts, it seems like this is a well-known issue
> > > related to incompatibility between particular versions of facelets and My
> > > Faces; are you aware on the latest on this, particularly as it relates to
> > > the "duplicate id in Faces tree" issue?
> >
> > No, I was not aware of any specific bug in Facelets related to duplicate
> > ids. Thanks for posting your findings; it might help someone.
> >
> > Sorry if my suggestion was wrong. Having problems with duplicate ids is
> > common when people mix jstl and jsf tags in *jsp* pages. And there are a
> > number of things that they just cannot do within JSF, particularly
> > related to looping components like tables. For some more info, see this
> > blog posting by Andrew Robinson:
> > http://andrewfacelets.blogspot.com/2006/06/creating-composite-controls-with-jsf.html
> >
> > I'm actually a little puzzled to hear that you are using JSTL and
> > *facelets*. I didn't think that Facelets works with jsp tags at all; as
> > far as I know, it completely ignores them. So I assumed that when you
> > initially said "facelets" that you had just used the wrong term. Are you
> > really using the facelets.dev.java.net project and jstl in the same
> > page?
> >
> > Regards,
> > Simon
> >
> >
Re: Duplicate id in faces tree error - removing JSTL?
Posted by Andrew Robinson <an...@gmail.com>.
Facelets implements partial support of JSTL. Jacob created TagHandlers
for the "popular" JSTL tags (if, choose, when, forEach). The tags
handlers reproduce the JSP behavior and have the same caveats of the
JSTL tags (run during component creation, not evaluation). In general,
you cannot use JSP tags in facelets. You only can if you create a
TagHandler that mimics the behavior and register it using the same
namespace to "fool" users to think that it is working out of the box.
-Andrew
On Fri, May 2, 2008 at 1:29 PM, simon <si...@chello.at> wrote:
>
>
> On Thu, 2008-05-01 at 09:20 -0700, mjovanov wrote:
> >
> > simon.kitching@chello.at wrote:
> > >
> > >
> > > On Mon, 2008-04-28 at 08:46 -0700, mjovanov wrote:
> > >> After upgrading to MyFaces 1.2.2 I am getting a "duplicate id in the
> > >> faces
> > >> tree" error. I have isolated it to the following section of code:
> > >>
> > >> <t:column id="${fieldName}" styleClass="${columnStyleClass}"
> > >> rendered="${renderValue}">
> > >>
> > >> <f:facet name="header">
> > >> <t:commandSortHeader columnName="${fieldName}" arrow="true"
> > >> actionListener="#{backingBean.sortChanged}"
> > >> immediate="true"
> > >> styleClass="cellDataHeader">
> > >> ${label}
> > >> </t:commandSortHeader>
> > >> </f:facet>
> > >>
> > >> <c:choose>
> > >> ...
> > >> ...
> > >> <c:when test="${empty secondaryFieldName}">
> > >>
> > >> <c:if test="${not empty linkAction}">
> > >> <h:commandLink action="#{backingBean.details}" immediate="true">
> > >> <c:choose>
> > >> <c:when test="${not empty dateFormat}">
> > >> <h:outputText value="${entity[fieldName]}">
> > >> <f:convertDateTime type="date" timeZone="${timeZone}"
> > >> dateStyle="${dateFormat}"
> > >> pattern="${datePattern}" />
> > >> </h:outputText>
> > >> </c:when>
> > >>
> > >> <c:when test="${not empty currencyPattern}">
> > >> <h:outputText value="${entity[fieldName]}">
> > >> <f:convertNumber pattern="${currencyPattern}" />
> > >> </h:outputText>
> > >> <br />
> > >> </c:when>
> > >>
> > >> <c:otherwise>
> > >> <h:outputText value="${entity[fieldName]}" />
> > >> </c:otherwise>
> > >> </c:choose>
> > >>
> > >> <f:param name="itemType" value="${linkAction}" />
> > >> <f:param name="fieldName" value="${fieldName}" />
> > >> <f:param name="addParam" value="${addParam}" />
> > >> </h:commandLink>
> > >>
> > >> The sections marked in bold indicate the components for which duplicate
> > >> ids
> > >> are being generated. I should also mention we are using facelets +
> > >> xhtml,
> > >> and the code listed above is in a facelet that is being invoked from the
> > >> main page.
> > >>
> > >> Reading some previous posts is seems the problem is most likely caused by
> > >> mixing JSTL and JSF tags; ideally I would want to remove the JSTL tags,
> > >> but
> > >> the facelet in question was not written by me and is quite long so I
> > >> would
> > >> only want to do this as a last resort.
> > >>
> > >> My question is: can anyone suggest an alternative solution to rewriting
> > >> the
> > >> facelet without JSTL tags? I realize I could also solve this issue by
> > >> explicitly naming the components but would like to understand better how
> > >> the
> > >> auto id generation works in MyFaces.
> > >>
> > >> Also, if the only "right" solution is to remove the JSTL tags, can
> > >> someone
> > >> suggest how to do this, considering they appear to be used extensively
> > >> (c:if, c:when…)?
> > >
> > > The only right solution is to remove the JSTL tags.
> > >
> > > Conditional tags are dangerous with any JSF component. And they are
> > > totally incompatible with JSF looping components like tables; this
> > > applies to JSF1.1 too.
> > >
> > > JSF is fundamentally a two-pass system (build component tree, then
> > > render component tree). This was only partially true in JSF1.1, but is
> > > completely true in JSF1.2. But JSTL is a one-pass system, and so
> > > conditional statements interacts very badly with JSF components that
> > > have significant behaviour in the second pass.
> > >
> > > I suggest that where a c:when or c:if wraps just one JSF component, then
> > > move the condition into a "rendered" attribute on that component. When
> > > it wraps more than one, then replace the JSTL tag with an h:panelGroup
> > > or t:div, and move the condition into the rendered attribute of that new
> > > tag. In most cases, that will do the trick.
> > >
> > > Note that JSTL *can* be used with JSF in some cases, but you really need
> > > to re-read and understand both the JSP specification bits about how tags
> > > work, and the JSF specification bits about the JSF lifecycle. So in
> > > general, it's best to avoid mixing them.
> > >
> > > Regards,
> > > Simon
> > >
> > >
> > >
> >
> > Hi Simon, thanks again for your quick response. We did go ahead and removed
> > the JSTL tags, but were surprised to find that did not take care of the
> > problem. So, after gradually removing parts of the code, I was able to
> > pinpoint it to our use of the Facelets. I tried upgrading from Facelets
> > 1.1.11 to 1.1.14 and, sure enough, that took care of it! Just wanted to
> > follow up, in case someone else experiences a similar issue.
> >
> > Searching through forum posts, it seems like this is a well-known issue
> > related to incompatibility between particular versions of facelets and My
> > Faces; are you aware on the latest on this, particularly as it relates to
> > the "duplicate id in Faces tree" issue?
>
> No, I was not aware of any specific bug in Facelets related to duplicate
> ids. Thanks for posting your findings; it might help someone.
>
> Sorry if my suggestion was wrong. Having problems with duplicate ids is
> common when people mix jstl and jsf tags in *jsp* pages. And there are a
> number of things that they just cannot do within JSF, particularly
> related to looping components like tables. For some more info, see this
> blog posting by Andrew Robinson:
> http://andrewfacelets.blogspot.com/2006/06/creating-composite-controls-with-jsf.html
>
> I'm actually a little puzzled to hear that you are using JSTL and
> *facelets*. I didn't think that Facelets works with jsp tags at all; as
> far as I know, it completely ignores them. So I assumed that when you
> initially said "facelets" that you had just used the wrong term. Are you
> really using the facelets.dev.java.net project and jstl in the same
> page?
>
> Regards,
> Simon
>
>
Re: Duplicate id in faces tree error - removing JSTL?
Posted by simon <si...@chello.at>.
On Thu, 2008-05-01 at 09:20 -0700, mjovanov wrote:
>
> simon.kitching@chello.at wrote:
> >
> >
> > On Mon, 2008-04-28 at 08:46 -0700, mjovanov wrote:
> >> After upgrading to MyFaces 1.2.2 I am getting a “duplicate id in the
> >> faces
> >> tree” error. I have isolated it to the following section of code:
> >>
> >> <t:column id="${fieldName}" styleClass="${columnStyleClass}"
> >> rendered="${renderValue}">
> >>
> >> <f:facet name="header">
> >> <t:commandSortHeader columnName="${fieldName}" arrow="true"
> >> actionListener="#{backingBean.sortChanged}"
> >> immediate="true"
> >> styleClass="cellDataHeader">
> >> ${label}
> >> </t:commandSortHeader>
> >> </f:facet>
> >>
> >> <c:choose>
> >> ...
> >> ...
> >> <c:when test="${empty secondaryFieldName}">
> >>
> >> <c:if test="${not empty linkAction}">
> >> <h:commandLink action="#{backingBean.details}" immediate="true">
> >> <c:choose>
> >> <c:when test="${not empty dateFormat}">
> >> <h:outputText value="${entity[fieldName]}">
> >> <f:convertDateTime type="date" timeZone="${timeZone}"
> >> dateStyle="${dateFormat}"
> >> pattern="${datePattern}" />
> >> </h:outputText>
> >> </c:when>
> >>
> >> <c:when test="${not empty currencyPattern}">
> >> <h:outputText value="${entity[fieldName]}">
> >> <f:convertNumber pattern="${currencyPattern}" />
> >> </h:outputText>
> >> <br />
> >> </c:when>
> >>
> >> <c:otherwise>
> >> <h:outputText value="${entity[fieldName]}" />
> >> </c:otherwise>
> >> </c:choose>
> >>
> >> <f:param name="itemType" value="${linkAction}" />
> >> <f:param name="fieldName" value="${fieldName}" />
> >> <f:param name="addParam" value="${addParam}" />
> >> </h:commandLink>
> >>
> >> The sections marked in bold indicate the components for which duplicate
> >> ids
> >> are being generated. I should also mention we are using facelets +
> >> xhtml,
> >> and the code listed above is in a facelet that is being invoked from the
> >> main page.
> >>
> >> Reading some previous posts is seems the problem is most likely caused by
> >> mixing JSTL and JSF tags; ideally I would want to remove the JSTL tags,
> >> but
> >> the facelet in question was not written by me and is quite long so I
> >> would
> >> only want to do this as a last resort.
> >>
> >> My question is: can anyone suggest an alternative solution to rewriting
> >> the
> >> facelet without JSTL tags? I realize I could also solve this issue by
> >> explicitly naming the components but would like to understand better how
> >> the
> >> auto id generation works in MyFaces.
> >>
> >> Also, if the only "right" solution is to remove the JSTL tags, can
> >> someone
> >> suggest how to do this, considering they appear to be used extensively
> >> (c:if, c:when…)?
> >
> > The only right solution is to remove the JSTL tags.
> >
> > Conditional tags are dangerous with any JSF component. And they are
> > totally incompatible with JSF looping components like tables; this
> > applies to JSF1.1 too.
> >
> > JSF is fundamentally a two-pass system (build component tree, then
> > render component tree). This was only partially true in JSF1.1, but is
> > completely true in JSF1.2. But JSTL is a one-pass system, and so
> > conditional statements interacts very badly with JSF components that
> > have significant behaviour in the second pass.
> >
> > I suggest that where a c:when or c:if wraps just one JSF component, then
> > move the condition into a "rendered" attribute on that component. When
> > it wraps more than one, then replace the JSTL tag with an h:panelGroup
> > or t:div, and move the condition into the rendered attribute of that new
> > tag. In most cases, that will do the trick.
> >
> > Note that JSTL *can* be used with JSF in some cases, but you really need
> > to re-read and understand both the JSP specification bits about how tags
> > work, and the JSF specification bits about the JSF lifecycle. So in
> > general, it's best to avoid mixing them.
> >
> > Regards,
> > Simon
> >
> >
> >
>
> Hi Simon, thanks again for your quick response. We did go ahead and removed
> the JSTL tags, but were surprised to find that did not take care of the
> problem. So, after gradually removing parts of the code, I was able to
> pinpoint it to our use of the Facelets. I tried upgrading from Facelets
> 1.1.11 to 1.1.14 and, sure enough, that took care of it! Just wanted to
> follow up, in case someone else experiences a similar issue.
>
> Searching through forum posts, it seems like this is a well-known issue
> related to incompatibility between particular versions of facelets and My
> Faces; are you aware on the latest on this, particularly as it relates to
> the "duplicate id in Faces tree" issue?
No, I was not aware of any specific bug in Facelets related to duplicate
ids. Thanks for posting your findings; it might help someone.
Sorry if my suggestion was wrong. Having problems with duplicate ids is
common when people mix jstl and jsf tags in *jsp* pages. And there are a
number of things that they just cannot do within JSF, particularly
related to looping components like tables. For some more info, see this
blog posting by Andrew Robinson:
http://andrewfacelets.blogspot.com/2006/06/creating-composite-controls-with-jsf.html
I'm actually a little puzzled to hear that you are using JSTL and
*facelets*. I didn't think that Facelets works with jsp tags at all; as
far as I know, it completely ignores them. So I assumed that when you
initially said "facelets" that you had just used the wrong term. Are you
really using the facelets.dev.java.net project and jstl in the same
page?
Regards,
Simon