There is the option to use the conditional task ("if") from ant-contrib... this
allows the nesting of a "sequential" task which itself can contain any tasks
you want.
-----Original Message-----
From: Sandip Chitale [mailto:[EMAIL PROTECTED]
Sent: Sun 29/05/2005 16:06
To: Ant Developers List
Cc:
Subject: Re: A possible solution for conditional execution of tasks?
Phil Weighill-Smith wrote:
>My opinion regarding the disadvantages of this approach:
>
>* Antcall has to create a whole new Project in memory in order to
work and is therefore an inefficient task
>
>
Yes. If the project is large this could be a large overhead. It seems
the semantics of antcall is not like a sub target but more like a target
in a sub project (even though the project happens to be the same
project). Is there a more lightweight solution planned in this area?
>* If something invoked via Antcall depends on a target that is
also depended on by something depending on the target invoking Antcall then
this dependency target will be executed more than once because dependencies are
not handled across Antcall invocations
>
>
Yes.
>* The dependency tree is "interrupted" and graphing tools that
can show ant build script structures will not (generally) work correctly and
show the whole dependency tree
>
>
I did not think about the graphing tools, but that is a good point also.
Given the fact that you did not list any advantages it seems this is not
a good idea.
>It might be better to add "if" and "unless" to the standard ant Task
to allow for conditional execution, or even add a nested "condition" to the
standard ant Task to allow for conditional execution. To provide BC with the
standard "execute" method, the condition/if/unless processing would need to
happen outside this method.
>
>
This seems like this is the real answer. However I read somewhere that
it is an architectural decision to not support "if" and "unless" etc. at
the task level. Can anyone point me to a discussion/document on that?
What about using scripting? Is that not recommended either?
Google search revealed that many people are looking for solutions for
similar problems.
Regards,
Sandip
>
>Phil :n.
>
> -----Original Message-----
> From: Sandip Chitale [mailto:[EMAIL PROTECTED]
> Sent: Sat 28/05/2005 18:56
> To: dev@ant.apache.org
> Cc:
> Subject: A possible solution for conditional execution of tasks?
>
>
>
> To conditionally execute a step in Ant one has to resort to
setting up a
> target structure like this:
>
> :
> <target name="predicate">
> <condition property="condition-satisfied">
> <available .../>
> :
> </condition>
> </target>
>
> <target name="conditional-step" if="condition-satisfied">
> <!-- conditional tasks here -->
> :
> :
> </target>
>
> <target name="conditional" depends="predicate,
conditional-step"/>
>
> <target name="main" depends="conditional">
> :
> :
> </target>
> :
>
> This is because of several reasons:
>
> * The ant tasks do not have something like *if* attribute.
> * One cannot get away with only two targets instead of
three because
> the dependencies are executed before the dependent. Using
the
> above example it is not possible to do what target
predicate does
> in the main target and avoid using the predicate target.
> * Ensure order of execution
>
> However, I tried a solution making use of antcall task and it
worked. It
> works as follows:
>
> :
> <target name="conditional-step" if="condition-satisfied">
> <!-- conditional tasks here -->
> :
> :
> </target>
>
> <target name="main" depends="conditional-step">
> :
> <condition property="condition-satisfied">
> <available .../>
> :
> </condition>
> <antcall target="condition-satisfied"/>
> :
> </target>
>
> The advantage of this approach is to quickly have some tasks
execute
> conditionally by putting them in a target and calling that
target using
> antcall after setting some property.
>
> And it seemed to work. My question is - is there a problem
using this
> approach? Why or why isn't this a preferred approach?
>
> Thanks in advance,
> Sandip
>
>
>
>
>
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