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Posted to ivy-user@ant.apache.org by Mitch Gitman <mg...@gmail.com> on 2009/01/22 06:51:29 UTC
classpath issues: trying to consume Ivy API in an Ant task
I have a very, very simple Ant task that consumes the Ivy API. That is, in
the Java code for my Ant task, I'm using Ivy classes. One class I had been
trying to use was IvyAntSettings. Well, look what happened when I tried to
cast a reference I found in the Ant project to an actual IvyAntSettings
object. It's the telltale sign of ClassLoader issues: you can't cast a class
to itself:
BUILD FAILED
java.lang.ClassCastException: org.apache.ivy.ant.IvyAntSettings cannot be
cast to org.apache.ivy.ant.IvyAntSettings
at org.myorg.ivy.IvyConsumerTask.execute(IvyConsumerTask.java:45)
It just so happened I realized I didn't need an IvyAntSettings instance, but
when I got rid of the IvyAntSettings cast, that just uncovered another
variation on the same ClassLoader problem:
BUILD FAILED
C:\...\build.xml:23: ivy.instance has been defined in a different
classloader. Please use the same loader when defining your task, or
redeclare your ivy:settings in this classloader
at org.apache.ivy.ant.IvyTask.getIvyInstance(IvyTask.java:82)
at org.apache.ivy.ant.IvyTask.prepareTask(IvyTask.java:256)
Now, I can tell you what makes this problem go away, although it's a measure
I would just as soon NOT resort to. Put ivy.jar and the JAR for my Ant task
in one of Ant's primordial classloading directories:
- ANT_HOME/lib
- USER_HOME/.ant/lib
Here's a minimal Ant target where I'm able to reproduce my problem. In this
target, the Ivy JAR and my tasks JAR are in the directory templib:
<target name="try-this">
<property name="ivy.settings.url" value="
http://localhost/ivy/myorg/ivysettings.xml" />
<property name="ivy.file" location="ivy.xml" />
<path id="temp.myorg.tasks.classpath">
<fileset dir="templib" includes="*.jar" />
</path>
<taskdef uri="antlib:org.apache.ivy.ant"
resource="org/apache/ivy/ant/antlib.xml"
classpathref="temp.myorg.tasks.classpath" />
<ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
<taskdef uri="antlib:org.myorg.tasks"
resource="org/myorg/tasks/tasks.properties"
classpathref="temp.myorg.tasks.classpath" />
<mynamespace:ivyconsumer
conf="default"
classpathid="some.classpath" />
</target>
I suppose I could define the Ivy settings programmatically within my Ant
task, but I shudder at the implications of that. I'm afraid that, suddenly,
all use of Ivy has to go indirectly through my own Ant task, or additional
tasks. My question is, is there any way, short of the extreme measures I've
already described, to get my custom Ant task to use the same classloader as
was used by?:
<ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
Re: classpath issues: trying to consume Ivy API in an Ant task
Posted by Mitch Gitman <mg...@gmail.com>.
Worked. Thanks, Maarten! I owe you a beer.
P.S. Disregard the potential workaround I'd just mentioned.
On Thu, Jan 22, 2009 at 8:32 AM, Maarten Coene <ma...@yahoo.com>wrote:
> You could try to use the same loaderRef attribute on the taskdefs where you
> load the Ivy tasks and your own tasks:
>
> <!-- load ivy tasks -->
> <taskdef resource="org/apache/ivy/ant/antlib.xml"
> uri="antlib:org.apache.ivy.ant" loaderRef="ivy.loader"
> classPathRef="ivy.classpath" />
> <!-- load own tasks -->
> <taskdef ... loaderRef="ivy.loader" classPathRef="yourtask.classpath" />
>
> This way, you can more or less choose where you put the jars I think...
>
> Maarten
>
>
>
>
> ----- Original Message ----
> From: Mitch Gitman <mg...@gmail.com>
> To: ivy-user@ant.apache.org
> Sent: Thursday, January 22, 2009 5:12:06 PM
> Subject: Re: classpath issues: trying to consume Ivy API in an Ant task
>
> Actually, let me try restating this query as a simpler question. Has anyone
> tried writing their own Ant task that consumes the Ivy API? If so, what
> decisions did you make as to the classpath location of the Ivy JAR and your
> task's JAR so that it would work? Thanks.
>
> On Wed, Jan 21, 2009 at 9:51 PM, Mitch Gitman <mg...@gmail.com> wrote:
>
> > I have a very, very simple Ant task that consumes the Ivy API. That is,
> in
> > the Java code for my Ant task, I'm using Ivy classes. One class I had
> been
> > trying to use was IvyAntSettings. Well, look what happened when I tried
> to
> > cast a reference I found in the Ant project to an actual IvyAntSettings
> > object. It's the telltale sign of ClassLoader issues: you can't cast a
> class
> > to itself:
> > BUILD FAILED
> > java.lang.ClassCastException: org.apache.ivy.ant.IvyAntSettings cannot be
> > cast to org.apache.ivy.ant.IvyAntSettings
> > at org.myorg.ivy.IvyConsumerTask.execute(IvyConsumerTask.java:45)
> >
> > It just so happened I realized I didn't need an IvyAntSettings instance,
> > but when I got rid of the IvyAntSettings cast, that just uncovered
> another
> > variation on the same ClassLoader problem:
> > BUILD FAILED
> > C:\...\build.xml:23: ivy.instance has been defined in a different
> > classloader. Please use the same loader when defining your task, or
> > redeclare your ivy:settings in this classloader
> > at org.apache.ivy.ant.IvyTask.getIvyInstance(IvyTask.java:82)
> > at org.apache.ivy.ant.IvyTask.prepareTask(IvyTask.java:256)
> >
> > Now, I can tell you what makes this problem go away, although it's a
> > measure I would just as soon NOT resort to. Put ivy.jar and the JAR for
> my
> > Ant task in one of Ant's primordial classloading directories:
> >
> > - ANT_HOME/lib
> > - USER_HOME/.ant/lib
> >
> > Here's a minimal Ant target where I'm able to reproduce my problem. In
> this
> > target, the Ivy JAR and my tasks JAR are in the directory templib:
> > <target name="try-this">
> > <property name="ivy.settings.url" value="
> > http://localhost/ivy/myorg/ivysettings.xml" />
> > <property name="ivy.file" location="ivy.xml" />
> > <path id="temp.myorg.tasks.classpath">
> > <fileset dir="templib" includes="*.jar" />
> > </path>
> > <taskdef uri="antlib:org.apache.ivy.ant"
> > resource="org/apache/ivy/ant/antlib.xml"
> > classpathref="temp.myorg.tasks.classpath" />
> > <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
> > <taskdef uri="antlib:org.myorg.tasks"
> > resource="org/myorg/tasks/tasks.properties"
> > classpathref="temp.myorg.tasks.classpath" />
> > <mynamespace:ivyconsumer
> > conf="default"
> > classpathid="some.classpath" />
> > </target>
> >
> > I suppose I could define the Ivy settings programmatically within my Ant
> > task, but I shudder at the implications of that. I'm afraid that,
> suddenly,
> > all use of Ivy has to go indirectly through my own Ant task, or
> additional
> > tasks. My question is, is there any way, short of the extreme measures
> I've
> > already described, to get my custom Ant task to use the same classloader
> as
> > was used by?:
> > <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
> >
> >
>
>
>
>
>
Re: classpath issues: trying to consume Ivy API in an Ant task
Posted by Maarten Coene <ma...@yahoo.com>.
You could try to use the same loaderRef attribute on the taskdefs where you load the Ivy tasks and your own tasks:
<!-- load ivy tasks -->
<taskdef resource="org/apache/ivy/ant/antlib.xml" uri="antlib:org.apache.ivy.ant" loaderRef="ivy.loader" classPathRef="ivy.classpath" />
<!-- load own tasks -->
<taskdef ... loaderRef="ivy.loader" classPathRef="yourtask.classpath" />
This way, you can more or less choose where you put the jars I think...
Maarten
----- Original Message ----
From: Mitch Gitman <mg...@gmail.com>
To: ivy-user@ant.apache.org
Sent: Thursday, January 22, 2009 5:12:06 PM
Subject: Re: classpath issues: trying to consume Ivy API in an Ant task
Actually, let me try restating this query as a simpler question. Has anyone
tried writing their own Ant task that consumes the Ivy API? If so, what
decisions did you make as to the classpath location of the Ivy JAR and your
task's JAR so that it would work? Thanks.
On Wed, Jan 21, 2009 at 9:51 PM, Mitch Gitman <mg...@gmail.com> wrote:
> I have a very, very simple Ant task that consumes the Ivy API. That is, in
> the Java code for my Ant task, I'm using Ivy classes. One class I had been
> trying to use was IvyAntSettings. Well, look what happened when I tried to
> cast a reference I found in the Ant project to an actual IvyAntSettings
> object. It's the telltale sign of ClassLoader issues: you can't cast a class
> to itself:
> BUILD FAILED
> java.lang.ClassCastException: org.apache.ivy.ant.IvyAntSettings cannot be
> cast to org.apache.ivy.ant.IvyAntSettings
> at org.myorg.ivy.IvyConsumerTask.execute(IvyConsumerTask.java:45)
>
> It just so happened I realized I didn't need an IvyAntSettings instance,
> but when I got rid of the IvyAntSettings cast, that just uncovered another
> variation on the same ClassLoader problem:
> BUILD FAILED
> C:\...\build.xml:23: ivy.instance has been defined in a different
> classloader. Please use the same loader when defining your task, or
> redeclare your ivy:settings in this classloader
> at org.apache.ivy.ant.IvyTask.getIvyInstance(IvyTask.java:82)
> at org.apache.ivy.ant.IvyTask.prepareTask(IvyTask.java:256)
>
> Now, I can tell you what makes this problem go away, although it's a
> measure I would just as soon NOT resort to. Put ivy.jar and the JAR for my
> Ant task in one of Ant's primordial classloading directories:
>
> - ANT_HOME/lib
> - USER_HOME/.ant/lib
>
> Here's a minimal Ant target where I'm able to reproduce my problem. In this
> target, the Ivy JAR and my tasks JAR are in the directory templib:
> <target name="try-this">
> <property name="ivy.settings.url" value="
> http://localhost/ivy/myorg/ivysettings.xml" />
> <property name="ivy.file" location="ivy.xml" />
> <path id="temp.myorg.tasks.classpath">
> <fileset dir="templib" includes="*.jar" />
> </path>
> <taskdef uri="antlib:org.apache.ivy.ant"
> resource="org/apache/ivy/ant/antlib.xml"
> classpathref="temp.myorg.tasks.classpath" />
> <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
> <taskdef uri="antlib:org.myorg.tasks"
> resource="org/myorg/tasks/tasks.properties"
> classpathref="temp.myorg.tasks.classpath" />
> <mynamespace:ivyconsumer
> conf="default"
> classpathid="some.classpath" />
> </target>
>
> I suppose I could define the Ivy settings programmatically within my Ant
> task, but I shudder at the implications of that. I'm afraid that, suddenly,
> all use of Ivy has to go indirectly through my own Ant task, or additional
> tasks. My question is, is there any way, short of the extreme measures I've
> already described, to get my custom Ant task to use the same classloader as
> was used by?:
> <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
>
>
Re: classpath issues: trying to consume Ivy API in an Ant task
Posted by Mitch Gitman <mg...@gmail.com>.
I think I have a potential workaround. Instead of using the Ivy settings
that the Ant project is aware of, construct a new IvyAntSettings object
that's essentially a copy of the existing one. IvyAntSettings is a fairly
involved class, so I'm not so sure that will work. Perhaps someone has had
experience with pulling this off.
P.S. This is a case where the error message from Ivy is actually quite
helpful:
C:\...\build.xml:23: ivy.instance.for.tasks has been defined in a different
classloader. Please use the same loader when defining your task, or
redeclare your ivy:settings in this classloader
For now, I'm following the advice, "or redeclare your ivy:settings in this
classloader."
On Thu, Jan 22, 2009 at 8:12 AM, Mitch Gitman <mg...@gmail.com> wrote:
> Actually, let me try restating this query as a simpler question. Has anyone
> tried writing their own Ant task that consumes the Ivy API? If so, what
> decisions did you make as to the classpath location of the Ivy JAR and your
> task's JAR so that it would work? Thanks.
>
>
> On Wed, Jan 21, 2009 at 9:51 PM, Mitch Gitman <mg...@gmail.com> wrote:
>
>> I have a very, very simple Ant task that consumes the Ivy API. That is, in
>> the Java code for my Ant task, I'm using Ivy classes. One class I had been
>> trying to use was IvyAntSettings. Well, look what happened when I tried to
>> cast a reference I found in the Ant project to an actual IvyAntSettings
>> object. It's the telltale sign of ClassLoader issues: you can't cast a class
>> to itself:
>> BUILD FAILED
>> java.lang.ClassCastException: org.apache.ivy.ant.IvyAntSettings cannot be
>> cast to org.apache.ivy.ant.IvyAntSettings
>> at org.myorg.ivy.IvyConsumerTask.execute(IvyConsumerTask.java:45)
>>
>> It just so happened I realized I didn't need an IvyAntSettings instance,
>> but when I got rid of the IvyAntSettings cast, that just uncovered another
>> variation on the same ClassLoader problem:
>> BUILD FAILED
>> C:\...\build.xml:23: ivy.instance has been defined in a different
>> classloader. Please use the same loader when defining your task, or
>> redeclare your ivy:settings in this classloader
>> at org.apache.ivy.ant.IvyTask.getIvyInstance(IvyTask.java:82)
>> at org.apache.ivy.ant.IvyTask.prepareTask(IvyTask.java:256)
>>
>> Now, I can tell you what makes this problem go away, although it's a
>> measure I would just as soon NOT resort to. Put ivy.jar and the JAR for my
>> Ant task in one of Ant's primordial classloading directories:
>>
>> - ANT_HOME/lib
>> - USER_HOME/.ant/lib
>>
>> Here's a minimal Ant target where I'm able to reproduce my problem. In
>> this target, the Ivy JAR and my tasks JAR are in the directory templib:
>> <target name="try-this">
>> <property name="ivy.settings.url" value="
>> http://localhost/ivy/myorg/ivysettings.xml" />
>> <property name="ivy.file" location="ivy.xml" />
>> <path id="temp.myorg.tasks.classpath">
>> <fileset dir="templib" includes="*.jar" />
>> </path>
>> <taskdef uri="antlib:org.apache.ivy.ant"
>> resource="org/apache/ivy/ant/antlib.xml"
>> classpathref="temp.myorg.tasks.classpath" />
>> <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
>> <taskdef uri="antlib:org.myorg.tasks"
>> resource="org/myorg/tasks/tasks.properties"
>> classpathref="temp.myorg.tasks.classpath" />
>> <mynamespace:ivyconsumer
>> conf="default"
>> classpathid="some.classpath" />
>> </target>
>>
>> I suppose I could define the Ivy settings programmatically within my Ant
>> task, but I shudder at the implications of that. I'm afraid that, suddenly,
>> all use of Ivy has to go indirectly through my own Ant task, or additional
>> tasks. My question is, is there any way, short of the extreme measures I've
>> already described, to get my custom Ant task to use the same classloader as
>> was used by?:
>> <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
>>
>>
>
Re: classpath issues: trying to consume Ivy API in an Ant task
Posted by Mitch Gitman <mg...@gmail.com>.
Actually, let me try restating this query as a simpler question. Has anyone
tried writing their own Ant task that consumes the Ivy API? If so, what
decisions did you make as to the classpath location of the Ivy JAR and your
task's JAR so that it would work? Thanks.
On Wed, Jan 21, 2009 at 9:51 PM, Mitch Gitman <mg...@gmail.com> wrote:
> I have a very, very simple Ant task that consumes the Ivy API. That is, in
> the Java code for my Ant task, I'm using Ivy classes. One class I had been
> trying to use was IvyAntSettings. Well, look what happened when I tried to
> cast a reference I found in the Ant project to an actual IvyAntSettings
> object. It's the telltale sign of ClassLoader issues: you can't cast a class
> to itself:
> BUILD FAILED
> java.lang.ClassCastException: org.apache.ivy.ant.IvyAntSettings cannot be
> cast to org.apache.ivy.ant.IvyAntSettings
> at org.myorg.ivy.IvyConsumerTask.execute(IvyConsumerTask.java:45)
>
> It just so happened I realized I didn't need an IvyAntSettings instance,
> but when I got rid of the IvyAntSettings cast, that just uncovered another
> variation on the same ClassLoader problem:
> BUILD FAILED
> C:\...\build.xml:23: ivy.instance has been defined in a different
> classloader. Please use the same loader when defining your task, or
> redeclare your ivy:settings in this classloader
> at org.apache.ivy.ant.IvyTask.getIvyInstance(IvyTask.java:82)
> at org.apache.ivy.ant.IvyTask.prepareTask(IvyTask.java:256)
>
> Now, I can tell you what makes this problem go away, although it's a
> measure I would just as soon NOT resort to. Put ivy.jar and the JAR for my
> Ant task in one of Ant's primordial classloading directories:
>
> - ANT_HOME/lib
> - USER_HOME/.ant/lib
>
> Here's a minimal Ant target where I'm able to reproduce my problem. In this
> target, the Ivy JAR and my tasks JAR are in the directory templib:
> <target name="try-this">
> <property name="ivy.settings.url" value="
> http://localhost/ivy/myorg/ivysettings.xml" />
> <property name="ivy.file" location="ivy.xml" />
> <path id="temp.myorg.tasks.classpath">
> <fileset dir="templib" includes="*.jar" />
> </path>
> <taskdef uri="antlib:org.apache.ivy.ant"
> resource="org/apache/ivy/ant/antlib.xml"
> classpathref="temp.myorg.tasks.classpath" />
> <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
> <taskdef uri="antlib:org.myorg.tasks"
> resource="org/myorg/tasks/tasks.properties"
> classpathref="temp.myorg.tasks.classpath" />
> <mynamespace:ivyconsumer
> conf="default"
> classpathid="some.classpath" />
> </target>
>
> I suppose I could define the Ivy settings programmatically within my Ant
> task, but I shudder at the implications of that. I'm afraid that, suddenly,
> all use of Ivy has to go indirectly through my own Ant task, or additional
> tasks. My question is, is there any way, short of the extreme measures I've
> already described, to get my custom Ant task to use the same classloader as
> was used by?:
> <ivy:settings id="ivy.instance" url="${ivy.settings.url}" />
>
>