Hello Peter.
Thank you for the advice! This should work indeed! I have not tried yet,
but from reading the code I'm quite sure it will. It's a bit less nice
(there are two properties instead of just one), but it will work.
Though I'm still not quite satisfied that a script works differently depending
on how its properties have been set by the caller. IMO the result of a script
should not depend on that.
It's like if a Java function taking an int parameter would work differently
depending on whether you passed it as "5" or "3+2".
Why are there so called user properties at all?
Thank you once again for the proposal.
Al
> Gesendet: Donnerstag, 31. Juli 2014 um 15:06 Uhr
> Von: "Peter West" <li...@pbw.id.au>
> An: "Ant Users List" <user@ant.apache.org>
> Betreff: Re: How to override a property that was set in the command line via
> "-D..."
>
> Peter West
>
> "...the kingdom of heaven is like a merchant in search of fine pearls, who,
> finding one pearl of great value, sold all that he had and bought it."
>
> Just define "well-known" properties which can be used from the command line,
> or set from within a master file, and define another "actual" property which
> will take precedence. Add logic to called.xml and siblings to assign the
> "public" value to the "actual" outfile variable. If the actual variable was
> set at a higher level, that setting will take precedence. Otherwise, the
> value from the "public" well-known property will become the value of the
> "actual" variable.
>
> Just make sure to document it within the file, so that someone trying to work
> out why the command line option didn't "take" will be able to find it.
>
> <project name="Main" default="run">
>
> <target name="run">
> <property name="outFileName" value="START"/>
> <echo>Main: outFileName: ${outFileName}</echo>
>
> <ant antfile="called.xml" target="run">
> <property name="realFileName" value="OTHER VALUE"/>
> </ant>
> </target>
>
> </project>
>
> <project name="called" default="run">
>
> <property name="realFileName" value="${outFileName}"/>
>
> <target name="run">
> <echo>called: outFileName: ${realFileName}</echo>
> </target>
>
> </project>
>
> Peter West
>
> "...the kingdom of heaven is like a merchant in search of fine pearls, who,
> finding one pearl of great value, sold all that he had and bought it."
>
>
> On 31 Jul 2014, at 10:02 pm, Al Le <al...@gmx.de> wrote:
>
> > Hello.
> >
> > Thank you for the quick reply.
> >
> > I know that properties are immutable and should not be redefined. But my
> > situation is,
> > that the caller (be it command line or an ant script) sets the property for
> > the called
> > script.
> >
> > If the property is defined not in the command line but in the script itself
> > (using the
> > 'property' task) then the property is substituted in the called script. Bit
> > if it's set
> > from the commnd line, it's not.
> >
> > I looked into the ant source code. The reason seems to be that the
> > properties that are
> > defined in the command line are set as *user* properties. Those properties
> > can't be
> > redefined even through direct calls to project.setProperty().
> >
> > How would you implement my goal (I hope it's clear what it is)?
> >
> > If the main script is like this:
> >
> > <project name="Main" default="run">
> >
> > <target name="run">
> > <property name="outFileName" value="START"/>
> > <echo>Main: outFileName: ${outFileName}</echo>
> >
> > <ant antfile="called.xml" target="run">
> > <property name="outFileName" value="OTHER VALUE"/>
> > </ant>
> > </target>
> >
> > </project>
> >
> > and I call it as "ant -f main.xml" (no "-D...") then the called script gets
> > the value
> > "OTHER VALUE".
> >
> > So why do the properties set from the command line get set as user
> > properties whereas
> > properties set by the "property" task are set as usual properties?
> >
> > I think they should be set in the same way.
> >
> > Cheers
> > Al
> >
> >
> >
> >> Gesendet: Donnerstag, 31. Juli 2014 um 12:15 Uhr
> >> Von: "Knuplesch, Jürgen" <juergen.knuple...@icongmbh.de>
> >> An: "Ant Users List" <user@ant.apache.org>
> >> Betreff: AW: How to override a property that was set in the command line
> >> via "-D..."
> >>
> >> Hello,
> >>
> >> because of the immutability of properties you have to redesign your
> >> scripts.
> >> The first time you set a property is it. You are usually not able t change
> >> it later.
> >> This is very important, because this is the only way to set properties
> >> from outside.
> >>
> >> Why does your command line call then use "-D-DoutFileName=START", when you
> >> don’t want it?
> >>
> >> Never do this, when you want to change the prop in your build.
> >> If "START" is your default, then set it in the called target / Ant file,
> >> in your case "called.xml"
> >>
> >> Its very important to understand why immutability is a feature and not a
> >> bug... (-;
> >>
> >> Juergen
> >>
> >>
> >>
> >>
> >>
> >> -----Ursprüngliche Nachricht-----
> >> Von: Al Le [mailto:al...@gmx.de]
> >> Gesendet: Donnerstag, 31. Juli 2014 11:10
> >> An: user@ant.apache.org
> >> Betreff: How to override a property that was set in the command line via
> >> "-D..."
> >>
> >> user@ant.apache.org
> >>
> >> How to override a property that was set in the command line via "-D..."
> >>
> >> Hello.
> >>
> >> Could someone please help me with the following situation?
> >>
> >> I have some ant scripts that are used in two ways:
> >>
> >> 1. Standalone build, i.e. the script is executed directly from the command
> >> line 2. As a part of a larger build -- then the script is called via 'ant'
> >> from another
> >> script (here we have a main and a called scripts).
> >>
> >> Each script uses a property 'outFileName' that specifies where to write
> >> some output to.
> >> Both the main and the called script use this property. The script gets the
> >> value of the property passed from the caller.
> >>
> >> The root script (i.e. the one called from the command line) gets passed
> >> the value of 'outFileName' via the "-DoutFileName=..." option.
> >>
> >> When the main script calls a called script, it may specify another value
> >> for the property 'outFileName' (using the nested 'property' element). The
> >> called script should notice no difference how it was called (i.e. whether
> >> it is called from the command line or as a called script from another
> >> script).
> >>
> >> Now the propblem: It turns out that the properties specified via "-D=..."
> >> are set as *user* properties. Hence it's not possible to redefine them via
> >> the nested elements. Ant not even using a script task with a call
> >> 'project.setProperty()'.
> >>
> >> How would you solve this situation? I would not like introduce properties
> >> with a different name, since my goal is to have scripts that can be
> >> 'customized' by specifying a property with a well known name
> >> ('outFileName') -- be it on the command line or trough a nested element of
> >> an ant task. Thik of it as of script interface.
> >>
> >> The only possible solution I can think of is to specify a custom property
> >> helper, but that's too much IMO and makes scripts not 'portable'.
> >>
> >> Here's an example that I hope would explain the problem (I use ant 1.8.4
> >> but I think the same problem would also occur with ant 1.9.x):
> >>
> >>
> >> -- Main build file 'main.xml' --
> >>
> >> <project name="Main" default="run">
> >>
> >> <target name="run">
> >> <echo>Main: outFileName: ${outFileName}</echo>
> >>
> >> <ant antfile="called.xml" target="run">
> >> <property name="outFileName" value="OTHER VALUE"/>
> >> </ant>
> >> </target>
> >>
> >> </project>
> >>
> >>
> >> -- Called build file 'called.xml' --
> >> <project name="Called" default="run">
> >>
> >> <target name="run">
> >> <echo>Called: outFileName: ${outFileName}</echo>
> >> </target>
> >>
> >> </project>
> >>
> >>
> >> -- Command line --
> >> ant -f main.xml -DoutFileName=START
> >>
> >>
> >> -- Actual output --
> >> run:
> >> [echo] Main: outFileName: START
> >> run:
> >> [echo] Called: outFileName: START
> >>
> >>
> >> -- Expected (desired) output --
> >> run:
> >> [echo] Main: outFileName: START
> >> run:
> >> [echo] Called: outFileName: OTHER VALUE
> >>
> >>
> >> Any help will be much appreciated.
> >>
> >> Al
> >>
> >> ---------------------------------------------------------------------
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> >>
> >>
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