Hi Todd-Could you provide a bit more contextWill you be implementing this
(web)application under J2EE server -or- perhaps a container such as Catalina or
Jetty?Generally these environments support their own classloader loading
algorithms depending on the capability and security characteristics of the
(web)application you will be implementing and which J2EE server and container
will be the implementor-Martin
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transmission.> Date: Wed, 21 Nov 2007 12:33:46 -0800> From: [EMAIL PROTECTED]>
To: user@ant.apache.org> Subject: Re: How do I set a classpath for my custom
task?> > Gilles,> > The user is providing implementations of an interface I
provide. Then> my code (which is called from my ant task) calls interface
methods.> So I'm not using reflection to call the method, just to get an>
instance of the users class.> > Can you point me to any code that shows how to
"create a classloader> that is a child of the classloader in which the
interface class is> loaded"? I'm assuming I need to actually launch my
application in a> new VM using the classloader I create - any pointers to code
that does> demonstrates that would be appreciated as well!> > Todd> > On Nov
21, 2007 12:00 PM, Gilles Scokart <[EMAIL PROTECTED]> wrote:> > That depends on
how you want to invoke the code of the user.> > If you are using only
reflection to creates the object, but also to invoke> > the method. The, it is
easier. You only have to create a classloader> > defined with the user
classpath.> > If you are only using reflection to create an instance o the user
object,> > then you are using interface implemented by the user object. Then it
is a> > little bit more complex. You need to create a classloader that is a
child> > of the classloader in which the interface class is loaded. And your
own> > code must also be loaded in a classloader that is the child of the> >
classloader in which the interface class is loaded (or the same).> >> > Gilles>
>> > 2007/11/21, todd runstein <[EMAIL PROTECTED]>:> >> > >> > > Ramu,> > >> >
> Thanks for the suggestions. I've looked at both of these options, but> > >
since this is a custom task that I'd like to include with an open> > > source
project, neither of those options are ideal. In the "taskdef",> > > I'd like
the user of my task to only have to specify where my jar file> > > is. However,
because my task uses classes written by the user, I'd> > > like them to define
that classpath in the task itself.> > >> > > To be honest, I may not completely
understand the entire problem yet.> > > Let me explain what I *think* the
problem is, and hopefully someone> > > can tell me how to fix it.> > >> > >
Here is the taskdef that I would ask users to include in their build> > >
script:> > >> > > <!-- classpathref needs to include migrate4j.jar so ant can
find AntTask> > > -->> > > <taskdef name="migrate"
classname="com.eroi.migrate.migration.AntTask"> > >
classpathref="lib.classpath" />> > >> > > Then, here's the actual task in use:>
> >> > > <!-- The migrate task needs to know where user supplied classes are
-->> > > <target name="run" depends="compile" >> > > <migrate> > > version="1">
> > url="jdbc:h2:~/testH2"> > > driver="org.h2.Driver"> > > username="sa"> > >
password=""> > > packagename="db.migrations"> > >
classpathref="user.classpath"> > > />> > > </target>> > >> > > Not to beat a
dead horse, but the taskdef needs to find my code and my> > > code needs to
find users code. I think that the classpath in the> > > taskdef is being used
to find my task (since the task loads properly),> > > but when code in my task
runs, it is too late to change the classpath> > > so my code can't find the
users classes. I don't want the user to do> > > anything they wouldn't do with
core ant tasks (except for the taskdef> > > entry). I've started looking at the
Java, Javac and JUnit tasks to> > > see how they do this, but it's not
immediately clear how to replicate> > > their behavior.> > >> > > I'm now
looking at the Commandline object to see how that might work> > > with Execute.
If anyone has experience using these classes, I welcome> > > any help! I may be
about to run into a brick wall, so if I'm> > > obviously going down the wrong
path, please let me know.> > >> > > Todd> > >> > >> > > On Nov 20, 2007 8:43
PM, Ramu Sethu <[EMAIL PROTECTED]> wrote:> > > > HI todd> > > >> > > > Have you
tried the following option ??> > > > 1. -lib option> > > > 2. classpath
attribute in taskdef> > > >> > > >> > > >> > > > On Nov 21, 2007 2:15 AM, todd
runstein <[EMAIL PROTECTED]> wrote:> > > >> > > > > I'm writing an ant task
that calls a Java class named Engine. Engine> > > > > is in a jar file that is
included in my taskdef using the classpath> > > > > tag. This all works great.>
> > > >> > > > > The problem I'm having is that one of Engine's methods calls>
> > > > "Class.forName()", trying to dynamically add a class file that is not>
> > > > in it's jar file. Here I'm getting a ClassNotFoundException. I've> > >
> > tried a few things to manually set the classpath that Ant uses, but> > > >
> I'm just hacking aimlessly and have had no luck. Could someone give> > > > >
me some direction to manually adding to the classpath that Engine will> > > > >
ultimately work with?> > > > >> > > > > Thanks in advance!> > > > >> > > > >
Todd> > > > >> > > > > --> > > > >> > > > >> > > > >
----------------------------------------------------------------------> > > > >
The only "dumb question" is the one you were too afraid to ask.> > > > >
________________________________________> > > > > Check out RouteRuler - Free
software for runners, cyclists, walkers,> > > etc.> > > > >
http://routeruler.sourceforge.net> > > > >
________________________________________> > > > >> > > > >
---------------------------------------------------------------------> > > > >
To unsubscribe, e-mail: [EMAIL PROTECTED]> > > > > For additional commands,
e-mail: [EMAIL PROTECTED]> > > > >> > > > >> > > >> > > >> > > > --> > > >
Thank you> > > > Ramu S> > > >> > > > If A is success in life, then A equals x
plus y plus z. Work is x; y is> > > > play; and z is keeping your mouth shut.>
> > > - Albert Einstein> > > >> > >> > >> > >> > > --> > >> > >> > >
----------------------------------------------------------------------> > > The
only "dumb question" is the one you were too afraid to ask.> > >
________________________________________> > > Check out RouteRuler - Free
software for runners, cyclists, walkers, etc.> > >
http://routeruler.sourceforge.net> > >
________________________________________> > >> > >
---------------------------------------------------------------------> > > To
unsubscribe, e-mail: [EMAIL PROTECTED]> > > For additional commands, e-mail:
[EMAIL PROTECTED]> > >> > >> >> >> > --> > Gilles Scokart> >> > > > -- > > >
----------------------------------------------------------------------> The
only "dumb question" is the one you were too afraid to ask.>
________________________________________> Check out RouteRuler - Free software
for runners, cyclists, walkers, etc.> http://routeruler.sourceforge.net>
________________________________________> >
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unsubscribe, e-mail: [EMAIL PROTECTED]> For additional commands, e-mail: [EMAIL
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