Re: [OT] RE: How to get the tag name from within a taglib class ?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Cris, On 9/15/20 13:18, Berneburg, Cris J. - US wrote: > CS> IMO, the JSP effort was a stepping-stone on a path to better > CS> technologies like Velocity, FreeMarker, and others. If I were > CS> king, JSP would just go away. Just my POV of course [...] > > cjb> what do you like better about Velocity, FreeMarker, etc. cjb> > more than JSP? > > CS> I started using Velocity years ago [...] It definitely has its > CS> warts but it's relatively actively maintained, and anything I > CS> need I can get in and do myself, submit patches, etc. CS> CS> > Advantages over JSP (IMHO): CS> CS> - Can't execute direct Java > code, ever CS> - Non-verbose syntax CS> - No limit on template > length [...] CS> - Easy to install POJO "tools" which just expose > Java objects CS> to the runtime so you can $tool.doSomething() > [...] CS> - Can load templates from anywhere (disk, DB, URL, etc.) > > Good to know! I also see that it is an ASF project. > > Is Velocity interpreted or compiled like JSP? I'm thinking of > performance impacts, like during loops. > > Answering my own question, the Velocity FAQ says, "Velocity > doesn't compile your templates. They are parsed into an AST > (abstract syntax tree) and that is what gets cached." Right. It's not really interpreted OR compiled. But it's not re-parsed on every request unless you configure it to do that. I've never had any performance complaints myself. - -chris -BEGIN PGP SIGNATURE- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl9ip94ACgkQHPApP6U8 pFhooxAAifqd19yhLdxBAdDJY1ttX0CWB3/F3PUZ0qf6NoHU/kN7tLi5oejQpJ2a YTeml+vO/jI/c6sF5A/6rPdKyx6rjiUercUFP6efMJH6z4zVitgGfshWiAwWiBur SkDGtWsFUnco1fFOcSB2mD42amOl6JVEmpUyjMdlBw3wxjUY+fofKLD5/H1u2gb0 IqBmpZr7gPnhOK03Iti2zdaUCAf+iAJ+rgjnuo/iXpDRIa2s3JFxdbY0192id5sv bMPzO4hwU7aaR7qARXY+LBMFrJyuh2ICfIaz9s5uR+S20fSipcGkVSDl9OqATEls pHM/ff8d7fLuozj6JgVR1jDfQLOHEYwMktgJ9I1Lst4C+FaHsWoShm0mailYxHf6 FvF/XCaCxQ1mgwslnbfXBV65tU6okOMnkmZDCG8otxT/KMyhTgtSyfj80ft2x4Tq 0IvPWm8ztwj3Tr/P7Vg2T4RX46ESHQ20i0CtcGtMaaWRlVdTcBRYSR/JRsa+Hrdq W0SJ2PTO7stjuPDYTSog/wrprwS2QwKrpkj7RVgVXsOUShHTV9aswIWZjW+jiJyA 3DlsmBMeXhLdrlMTw8i1/fvHa+TtPjHoFvSH6sAHs3xX+QbLV3+bJ6/Z3+BU0V3N H76kobuPTXwEZXJ4y5TgY4Q8Jj/NQDwbnL+Si1Ut+gCpNlaD+B8= =O8Ce -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: [OT] RE: How to get the tag name from within a taglib class ?
Thanks Chris! CS> IMO, the JSP effort was a stepping-stone on a path to better CS> technologies like Velocity, FreeMarker, and others. If I were CS> king, JSP would just go away. Just my POV of course [...] cjb> what do you like better about Velocity, FreeMarker, etc. cjb> more than JSP? CS> I started using Velocity years ago [...] It definitely has its CS> warts but it's relatively actively maintained, and anything I CS> need I can get in and do myself, submit patches, etc. CS> CS> Advantages over JSP (IMHO): CS> CS> - Can't execute direct Java code, ever CS> - Non-verbose syntax CS> - No limit on template length [...] CS> - Easy to install POJO "tools" which just expose Java objects CS> to the runtime so you can $tool.doSomething() [...] CS> - Can load templates from anywhere (disk, DB, URL, etc.) Good to know! I also see that it is an ASF project. Is Velocity interpreted or compiled like JSP? I'm thinking of performance impacts, like during loops. Answering my own question, the Velocity FAQ says, "Velocity doesn't compile your templates. They are parsed into an AST (abstract syntax tree) and that is what gets cached." -- Cris Berneburg CACI Senior Software Engineer This electronic message contains information from CACI International Inc or subsidiary companies, which may be company sensitive, proprietary, privileged or otherwise protected from disclosure. The information is intended to be used solely by the recipient(s) named above. If you are not an intended recipient, be aware that any review, disclosure, copying, distribution or use of this transmission or its contents is prohibited. If you have received this transmission in error, please notify the sender immediately.
Re: [OT] RE: How to get the tag name from within a taglib class ?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Cris, On 9/14/20 15:04, Berneburg, Cris J. - US wrote: > Hey Chris > > CS> IMO, the JSP effort was a stepping-stone on a path to better > CS> technologies like Velocity, FreeMarker, and others. If I were > CS> king, JSP would just go away. Just my POV of course, you are > CS> welcome to fall in love with JSP. :) > > Seeing as I am ever on the trailing edge of learning new or even > dated technologies, what do you like better about Velocity, > FreeMarker, etc. more than JSP? I started using Velocity years ago because it was bundled with Turbine which was being used by a project I got pulled-into. We eventually ripped everything else out, but Velocity survived. I looked at FreeMarker when doing a book review for Apache Struts 2 and it looked very interesting, but I discovered that the guy running the project was ... difficult to work with. SO I've stuck with Velocity for a long time. It definitely has its warts but it's relatively actively maintained, and anything I need I can get in and do myself, submit patches, etc. Advantages over JSP (IMHO): - - Can't execute direct Java code, ever - - Non-verbose syntax - - No limit on template length (JSP eventually hits the "Method too long" problem which is very inconvenient) - - Easy to install POJO "tools" which just expose Java objects to the runtime so you can $tool.doSomething() and it'll do whatever that is, converting the result to a String and dropping it into the output - - Can load templates from anywhere (disk, DB, URL, etc.) - -chris -BEGIN PGP SIGNATURE- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl9gyksACgkQHPApP6U8 pFi2og//TI//2oxfo4iE3q0B1f4sMN8fT8K9EVT89EME1jfUHontVRXtrX+tke2f t/3Os9veBJROAO5jOJvBCkefq7V2Lqij2289Vc7qVuuap+UqO/a+UCyOjxmVAHGh TrMeuxRLV8V1GPhDo0pftoJEWXg6SnDEqo7TF/1kGAmcaHEkWUEYrOPLfE92GbHJ 8bNySZFEleXX3decZj1mBdAoL+SMV7jbSvONGrMDds0saAddUmYMpdP9VPnCnKfG YS5Ec1Hx/1hshUisC1qOuarNCXH+84MLV98yM1pECoYCzx+2rTZ9RdoLwDnHjJB2 wJrc66P0yHOXyBfMamfpaxsUvTj2PON6RwBcbC7gaDMLIefGWM8TUROXMf7Odd40 TDZ+uJvyZBApeCnHkKrY/ipEvT4qb5sF0pVZTV9N6EBfqhKwBXgNqxTpCnAOkYFq egXYO1JGShxCdnHfAgNHyMoZ61PLltwe5msW6ZTlAqex3teZkmIrVfXXINy/JEbs lcRxe/V1EPBk9JxPJMy+hgDx4RBk6/ocepJbT2BR8nA9R1LBvA5h7wMr9iQw091S pbBr7xuKnIncMuCqTTyjiPZV/+7fBRYZgGAqZX+2pNGJkZ+kNMm3FAPqz9pjw/LD 2DZyK7gqXmFCWGGdlWxLfPOpNb6ajv3slc3fMXxvdBNNpW1AYg8= =AwcX -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
[OT] RE: How to get the tag name from within a taglib class ?
Hey Chris CS> IMO, the JSP effort was a stepping-stone on a path to better CS> technologies like Velocity, FreeMarker, and others. If I were CS> king, JSP would just go away. Just my POV of course, you are CS> welcome to fall in love with JSP. :) Seeing as I am ever on the trailing edge of learning new or even dated technologies, what do you like better about Velocity, FreeMarker, etc. more than JSP? -- Cris "NOT Trying to Start a Flame War" Berneburg CACI Senior Software Engineer This electronic message contains information from CACI International Inc or subsidiary companies, which may be company sensitive, proprietary, privileged or otherwise protected from disclosure. The information is intended to be used solely by the recipient(s) named above. If you are not an intended recipient, be aware that any review, disclosure, copying, distribution or use of this transmission or its contents is prohibited. If you have received this transmission in error, please notify the sender immediately. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
RE: How to get the tag name from within a taglib class ?
Rony RF> If possible I would like to write a single tagclass, but use it RF> for two or more different tags, as the implementation would share RF> quite a lot of code. Besides, it might be helpful for debugging. CS> Feel free to build a base class with the shared code and then implement CS> the differences in subclasses. Sure, implementing a sub-class of TagSupport that acts as a custom tag super-class works fine. RF> I would have a need to find out the tag name RF> that caused the tagclass to run. RF> RF> Is this possible? If so, how would one be able to get at RF> that tag name (any brief hints would suffice) ? Not sure exactly what you mean... Here's an example: - CustomTagImplementation.java contains: public class CustomTagImplementation extends TagSupport - tags.tld contains: CustomTag1 tags.CustomTagImplementation CustomTag2 tags.CustomTagImplementation - page.jsp contains: Are either of these what you mean? A. Get surrounding tag "" - TagSupport/CustomTagImplementation/getParent(), for calculating something like an xpath? B. Get tag definition name "CustomTag1" - Ouch. Sorry, no help there. How about an intellectual exercise to kill some time? :-) Suppose you had a map of classes and associated tag names from either parsing tags.tld directly or exposing whatever structure holds classes instantiated from it. You might still have a lookup problem due to a one-to-many relationship. Using CustomTagImplementation/getClassName() as the map lookup key would have 2 theoretical answers, both "CustomTag1" and "CustomTag2". By the time the page code is executed, the JSP has aleady been compiled. Looking at pre-compiled org/apache/jsp/page_jsp.java, each call to gets its own _jspx_meth_* method. There is a comment in each method, "// tags:CustomTag1". Seems kinda messy in there, and potentially fragile to depend on the pre-compiler output format. It's too bad TagSupport is not auto-magically fed as a parameter the name of tag definition in the page that "called" it. All in the engine, no changes to JSP pages. While I have not used it myself, have you looked at SimpleTagSupport to see if it has something useful? -- Cris Berneburg CACI Senior Software Engineer This electronic message contains information from CACI International Inc or subsidiary companies, which may be company sensitive, proprietary, privileged or otherwise protected from disclosure. The information is intended to be used solely by the recipient(s) named above. If you are not an intended recipient, be aware that any review, disclosure, copying, distribution or use of this transmission or its contents is prohibited. If you have received this transmission in error, please notify the sender immediately. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: How to get the tag name from within a taglib class ?
Hi Chris,
On 11.09.2020 19:31, Christopher Schultz wrote:
> > P.S.: If possible I would like to write a single tagclass, but use
> > it for two or more different tags, as the implementation would
> > share quite a lot of code. Besides, it might be helpful for
> > debugging.
>
> It seems like this is the wrong approach, unless you just want to use
> this for something like logging.
Not logging, but support for scripting languages.
> I you want the tags to behave differently, then you should have
> separate tag implementations.
In this case the only difference would be that in one case ("script",
"scriptlet") a return value
gets ignored, in the other case ("expression") the return value is used to
print its string value to
the JSPWriter ("out").
> Feel free to build a base class with the shared code and then implement the
> differences in subclasses.
Yes, if there is no easy way to learn about the tag that the tagclass got
invoked for, which seems
to be the case here.
> It's been a lng time since I wrote a custom tag library but I do
> remember that the whole process was very painful and despite the
> flexibility allowed by the API, lots of common things (like getting
> the tag name!) were either awkward or impossible.
Well, it is not really "painful", just a lot of power, many roads that could be
chosen and
flexibility at hand which at times is overwhelming for a newbie in this corner,
hence my brief
question. :)
> IMO, the JSP effort was a stepping-stone on a path to better
> technologies like Velocity, FreeMarker, and others. If I were king,
> JSP would just go away. Just my POV of course, you are welcome to fall
> in love with JSP. :)
This assumes that the JSPs get written in Java only and one is ready to take on
the learning curves
for additional frameworks.
In this case the aim is to allow scripting languages either via Apache BSF [1]
(like Groovy
implemented in Java, ooRexx implemented in C++) or via the Java scripting
framework [2] ("JSR-223"
[3], "javax.script") to be used for writing JSPs. This may not be
attractive/interesting for
Java-savvy programmers who would create their server pages in Java, but it is
*very* attractive,
even important for non-Java programmers who know one of the supported scripting
languages.
In the end it should be easy to use Tomcat as the (Java-implemented) web server
for web applications
that get implemented in other programming languages. Very much like the Apache
web server [4] which
is written in C and allows other programming languages to exploit it.
---rony
P.S.: Maybe I should come up with a brief posting that tries to explain why it
is important to
support non-Java programming languages in JSPs by default (and if
interestesting to the Tomcat
community I can offer the code under AL, once it is done). Not sure whether all
in the Tomcat
community know that Apache BSF ("Bean Scripting Framework") was created
originally to allow
scripting languages to be used in JSPs! Hence I was very surprised to learn
that scripting languages
are not supported in Tomcat by default.
[1] "Apache Bean Scripting Framework (BSF)":
[3] "JSR-223", the "Java specification request 223":
or
[4] "Apache Web Server", "Apache HTTP Server Project":
Re: How to get the tag name from within a taglib class ?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA256 Rony, On 9/11/20 10:28, Rony G. Flatscher (Apache) wrote: > While exploring, experimenting with creating a taglib (implementing > the BodyTag interface) I would have a need to find out the tag name > that caused the tagclass to run. > > Is this possible? If so, how would one be able to get at that tag > name (any brief hints would suffice) ? > > ---rony > > P.S.: If possible I would like to write a single tagclass, but use > it for two or more different tags, as the implementation would > share quite a lot of code. Besides, it might be helpful for > debugging. It seems like this is the wrong approach, unless you just want to use this for something like logging. I you want the tags to behave differently, then you should have separate tag implementations. Feel free to build a base class with the shared code and then implement the differences in subclasses. It's been a lng time since I wrote a custom tag library but I do remember that the whole process was very painful and despite the flexibility allowed by the API, lots of common things (like getting the tag name!) were either awkward or impossible. IMO, the JSP effort was a stepping-stone on a path to better technologies like Velocity, FreeMarker, and others. If I were king, JSP would just go away. Just my POV of course, you are welcome to fall in love with JSP. :) - -chris -BEGIN PGP SIGNATURE- Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAl9btG8ACgkQHPApP6U8 pFiYyhAAxG/8tTbGEp9pN3RvxjvRQXf+UupG4S3CXQNoNeVr4ffpWWii0kLHLLpj YoBpqNUjsl4Uki2jLADPioUHKdLOmVSlL6NTEcgMyEdIrCsI1A49okpnAIIX5EVB SRbfiUnv+37zQrKn3HbNnW8p6OoANHaEpGyfP6ylv6nj85nm9eAmXeKy/BcQLrI3 qRPD4migbvxGSU5M36YbT74q4azYV0bXEDh/9M3+Ky6iuPGGe0H+Y6V/JoERQt6d X3+QFxNWPxWW/BEoWkNjKfLHJgbYWQC5mgk7kK3u82DUV6fqGE95tiimhmSQwz8t qfeS/nDVVCh2c2hARneHriD8LV7ve62gjfY0y6BfXJG8Jl0vg6kokgdGu9hABLDG bj/BYjznC8qipN2I/X7Rn5eEr7RzxmMN3WigOFjsh4fUWNzcT6EP2CIphnmifPFx gIwj7SPuWmB8itN2MV4EouF+MkEB9LSPQGeDxYn+hTnfucbVjlH9QVJ5vQDGyGkr ZbmMB7HdriDj1CRWO22y2sxGHkKjRTb/uzkfy0XDNCJpw1SswaVcm9lep+aVq1zc ocKGS8PTbFiSKGLHt+ythKqTcwWhFjStXgGxPVntw/aBzlfIfIUlA8bsteWAH6Ic Go27fA6u0bBp+afq6gYbkTtGSY/leaFi1xfwX0G5uAT/AAVdObc= =2h8G -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
How to get the tag name from within a taglib class ?
While exploring, experimenting with creating a taglib (implementing the BodyTag interface) I would have a need to find out the tag name that caused the tagclass to run. Is this possible? If so, how would one be able to get at that tag name (any brief hints would suffice) ? ---rony P.S.: If possible I would like to write a single tagclass, but use it for two or more different tags, as the implementation would share quite a lot of code. Besides, it might be helpful for debugging. - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
