taglib functions in freemarker

[Jochen Fliedner]

hi templaters!

i understand that i can use any j2ee taglib tag in freemarker, also i can use those cool freemarker functions.

does anybody know, if it is possible to use taglib *functions* within freemarker templates/paragraphs, resp how-to accomplish that?

background:
we plan to use stk and stk best practices eg freemarker templating, also fell in love with openutils simple media module which usage is very much based on taglib functions, as of
http://lab.openmindonline.it/lab/products/media/docs/integrate.html - see "taglibdocs".


taglib functions within freemarker? anybody let me know...

regards
jf

----------------------------------------------------------------
For list details see
http://www.magnolia-cms.com/home/community/mailing-lists.html
To unsubscribe, E-mail to: <user-list-unsubscribe@...>
----------------------------------------------------------------

[Nils Breunese-2]

Jochen Fliedner wrote:

> i understand that i can use any j2ee taglib tag in freemarker, also i
> can use those cool freemarker functions.
>
> does anybody know, if it is possible to use taglib *functions* within
> freemarker templates/paragraphs, resp how-to accomplish that?
>
> background: we plan to use stk and stk best practices eg freemarker
> templating, also fell in love with openutils simple media module
> which usage is very much based on taglib functions, as of
> http://lab.openmindonline.it/lab/products/media/docs/integrate.html -
> see "taglibdocs".
>
>
> taglib functions within freemarker? anybody let me know...

Does the 'JSP Tags' section at
http://documentation.magnolia-cms.com/reference/freemarker.html answer
your question?

Nils Breunese.

----------------------------------------------------------------
For list details see
http://www.magnolia-cms.com/home/community/mailing-lists.html
To unsubscribe, E-mail to: <user-list-unsubscribe@...>
----------------------------------------------------------------

[Ernst Bunders]

2009/11/12 Nils Breunese <n.breunese@...>:

>
> Jochen Fliedner wrote:
>
>> i understand that i can use any j2ee taglib tag in freemarker, also i
>> can use those cool freemarker functions.
>>
>> does anybody know, if it is possible to use taglib *functions* within
>> freemarker templates/paragraphs, resp how-to accomplish that?
>>
>> background: we plan to use stk and stk best practices eg freemarker
>> templating, also fell in love with openutils simple media module
>> which usage is very much based on taglib functions, as of
>> http://lab.openmindonline.it/lab/products/media/docs/integrate.html -
>> see "taglibdocs".
>>
>>
>> taglib functions within freemarker? anybody let me know...
>
> Does the 'JSP Tags' section at
> http://documentation.magnolia-cms.com/reference/freemarker.html answer your
> question?
>

Nope, it does not. This is indeed something I stumbled upon myself,
asked before on this list, and am currently inclined to believe
unsupported.
There is no information (i could find) on the web about freemaker and
EL functions.

But there is one thing I still need to try: As EL functions tend to be
static methods, it should be possible to call them directly. I don't
know enough about freemarker yet to be sure you can just do something
like ${path.to.Class.staticMethod(param1, paran2)}, but I expect you
can.

If it turns out that you can't you can perhaps extend the
FreemarkerTemplateRenderer or STKTemplateRenderer class and add a
reference to this class to the template rendering context.

regards,

Ernst

> Nils Breunese.
>
> ----------------------------------------------------------------
> For list details see
> http://www.magnolia-cms.com/home/community/mailing-lists.html
> To unsubscribe, E-mail to: <user-list-unsubscribe@...>
> ----------------------------------------------------------------
>
>



--
Ernst bunders
Ontwikkelaar VPRO

----------------------------------------------------------------
For list details see
http://www.magnolia-cms.com/home/community/mailing-lists.html
To unsubscribe, E-mail to: <user-list-unsubscribe@...>
----------------------------------------------------------------

[Ernst Bunders]

2009/11/12 Ernst Bunders <ebunders@...>:

> 2009/11/12 Nils Breunese <n.breunese@...>:
>>
>> Jochen Fliedner wrote:
>>
>>> i understand that i can use any j2ee taglib tag in freemarker, also i
>>> can use those cool freemarker functions.
>>>
>>> does anybody know, if it is possible to use taglib *functions* within
>>> freemarker templates/paragraphs, resp how-to accomplish that?
>>>
>>> background: we plan to use stk and stk best practices eg freemarker
>>> templating, also fell in love with openutils simple media module
>>> which usage is very much based on taglib functions, as of
>>> http://lab.openmindonline.it/lab/products/media/docs/integrate.html -
>>> see "taglibdocs".
>>>
>>>
>>> taglib functions within freemarker? anybody let me know...
>>
>> Does the 'JSP Tags' section at
>> http://documentation.magnolia-cms.com/reference/freemarker.html answer your
>> question?
>>
>
> Nope, it does not. This is indeed something I stumbled upon myself,
> asked before on this list, and am currently inclined to believe
> unsupported.
> There is no information (i could find) on the web about freemaker and
> EL functions.
>
> But there is one thing I still need to try: As EL functions tend to be
> static methods, it should be possible to call them directly. I don't
> know enough about freemarker yet to be sure you can just do something
> like ${path.to.Class.staticMethod(param1, paran2)}, but I expect you
> can.
>
> If it turns out that you can't you can perhaps extend the
> FreemarkerTemplateRenderer or STKTemplateRenderer class and add a
> reference to this class to the template rendering context.

I found out that indeed the TemplateRenderer class has to be extended.
It turns out you have to wrap any java objects you want in your
freemaker objects in so called 'bean wrappers'. here is a snippet of
code that shows how to wrap some class in such a way that all static
methods become available:

BeansWrapper wrapper = BeansWrapper.getDefaultInstance();
TemplateHashModel staticModels = wrapper.getStaticModels();
TemplateHashModel fileStatics =
    (TemplateHashModel) staticModels.get("java.io.File");

assuming 'root' is your context object, you can:
root.put("File", fileStatics);

and then in the template do this:
<#list File.listRoots() as fileSystemRoot>...</#list>

So this can also be done with static EL function methods.

regards,

Ernst

>
> regards,
>
> Ernst
>
>> Nils Breunese.
>>
>> ----------------------------------------------------------------
>> For list details see
>> http://www.magnolia-cms.com/home/community/mailing-lists.html
>> To unsubscribe, E-mail to: <user-list-unsubscribe@...>
>> ----------------------------------------------------------------
>>
>>
>
>
>
> --
> Ernst bunders
> Ontwikkelaar VPRO
>

--
Ernst bunders
Ontwikkelaar VPRO

----------------------------------------------------------------
For list details see
http://www.magnolia-cms.com/home/community/mailing-lists.html
To unsubscribe, E-mail to: <user-list-unsubscribe@...>
----------------------------------------------------------------

[Nils Breunese-2]

Ernst Bunders wrote:

> 2009/11/12 Nils Breunese <n.breunese@...>:
>> Jochen Fliedner wrote:
>>> taglib functions within freemarker? anybody let me know...
>> Does the 'JSP Tags' section at
>> http://documentation.magnolia-cms.com/reference/freemarker.html answer your
>> question?
>
> Nope, it does not. This is indeed something I stumbled upon myself,
> asked before on this list, and am currently inclined to believe
> unsupported.
> There is no information (i could find) on the web about freemaker and
> EL functions.

That page says: "FreeMarker optionally supports JSP tag libraries, and
we have enabled this feature in Magnolia too. You can use any tag
library in your FreeMarker, and that means you can use the Magnolia tags
too."

I haven't tried it yet, but are you saying that it is not true that you
can use any tag library?

Nils Breunese.

----------------------------------------------------------------
For list details see
http://www.magnolia-cms.com/home/community/mailing-lists.html
To unsubscribe, E-mail to: <user-list-unsubscribe@...>
----------------------------------------------------------------

[Ernst Bunders]

> That page says: "FreeMarker optionally supports JSP tag libraries, and we
> have enabled this feature in Magnolia too. You can use any tag library in
> your FreeMarker, and that means you can use the Magnolia tags too."

That's right. But i think there is a clear distinction between EL
functions, which actually is a feature of the (jsp) Expression
Language, and jsp Tags. The two are bound together only in the tld, I
suppose. Support for tag libraries and thus tags is well documented
(and used by magnolia), but the same does not seem to apply to EL
functions.
But I'm not sure. I just couldn't find any documentation on this
subject, and my attempts to use EL functions from a taglib. did not
succeed :-(

regards,

Ernst

----------------------------------------------------------------
For list details see
http://www.magnolia-cms.com/home/community/mailing-lists.html
To unsubscribe, E-mail to: <user-list-unsubscribe@...>
----------------------------------------------------------------

[Jochen Fliedner]

Hi Ernst,

>> If it turns out that you can't you can perhaps extend the
>> FreemarkerTemplateRenderer or STKTemplateRenderer class and add a
>> reference to this class to the template rendering context.
>
>I found out that indeed the TemplateRenderer class has to be extended.
>It turns out you have to wrap any java objects you want in your
>freemaker objects in so called 'bean wrappers'. here is a snippet of
>code that shows how to wrap some class in such a way that all static
>methods become available:
>
>BeansWrapper wrapper = BeansWrapper.getDefaultInstance();
>TemplateHashModel staticModels = wrapper.getStaticModels();
>TemplateHashModel fileStatics =
>    (TemplateHashModel) staticModels.get("java.io.File");
>
>assuming 'root' is your context object, you can:
>root.put("File", fileStatics);
>
>and then in the template do this:
><#list File.listRoots() as fileSystemRoot>...</#list>
>
>So this can also be done with static EL function methods.

Thats cool!

I think a FreemarkerHelper subclass is the correct place to do such thing. One can subclass FreemarkerTemplateRenderer (Justas  STKParagraphRenderer does) and construct it with an own helper class - so you have an own renderer for your project.

Also you can implement model classes and use MediaEl within it. It makes sense as a kind of MVC pattern anyway.


I checked the freemarker code and it became obvious to me that indeed there is no generic taglib functions support. (Correct me if I am wrong!)
Anyway it might collide with the freemarker EL syntax, as i did like

[#assign media=JspTaglibs["http://net.sourceforge.openutils/mgnlMedia"]]
<img src="${contextPath}/${media}" alt="XXX" />

it resulted in

freemarker.core.NonStringException: Error on line 12, column 36 in templating-kit/paragraphs/teasers/internalPage.
Expecting a string, date or number here, Expression media is instead a freemarker.ext.jsp.TaglibFactory$Taglib


Of course ${media:something}, ${media.something}... no way.


However I can go on with the mentioned solution in our project.


Thanks a lot, regards
j

----------------------------------------------------------------
For list details see
http://www.magnolia-cms.com/home/community/mailing-lists.html
To unsubscribe, E-mail to: <user-list-unsubscribe@...>
----------------------------------------------------------------