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Posted to users@maven.apache.org by TimHedger <Ti...@rbos.com> on 2006/07/09 20:34:05 UTC
Build time classpath using my java plugin
I've written a plugin (in Java) that explicitly invokes the main method of a
Java class directly from within the jvm that maven is already running. My
plugin is behaving/configured as I expect, but I have a classpath problem
when control switches from my plugin code to the main method of the Java
class it invokes.
I use the following method to print the classpath before I invoke the main
method on my target class:
project.getCompileClasspathElements();
(where project is MavenProject)
And I get the list of jars I expect, including:
/home/hedgert/.m2/repository/javax/servlet/servlet-api/2.4/servlet-api-2.4.jar
which is the copy of javax.servlet that I have in my local maven repository.
Great - so far so good.
I invoke the main method of my target class and the code runs and then falls
over with a:
java.lang.NoClassDefFoundError: javax/servlet/ServletException
If I check the contents of my servlet-api-2.4.jar:
: jar -tf
/home/hedgert/.m2/repository/javax/servlet/servlet-api/2.4/servlet-api-2.4.jar
|grep ServletException
javax/servlet/ServletException.class
The missing class is indeed in the jar that is on the classpath.
So presumably the classpath I'm getting back from:
project.getCompileClasspathElements();
is not actually the classpath in operation when I invoke the main method on
my class from within a running JVM.
So my question is: maven has nicely worked out the classpath I need (using
the dependencies in my pom.xml file for my target project, rather than my
plugin), how do I get this classpath be active in the running JVM?
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Re: Build time classpath using my java plugin
Posted by Trygve Laugstøl <tr...@apache.org>.
TimHedger wrote:
> OK, so now I'm using the exec-plugin instead of my own code - great.
> But I've lost the control I had over when the exec step happened.
>
> I am using the plugin to generate SOAP wrappers for some Java code using
> glue (themindelectric). This step involves running a Java class with
> certain parameters and it creates various xml files and a directory
> structure, ready for packing into a war for distribution.
>
> My problem is this is happening every time I compile using maven. I've lost
> any control over checking whether source is stale and thus the soap/exec
> step if nothing's changed since my last build.
>
> How can I get this control with the exec plugin?
You can't, the exec plugin does not have that kind of knowledge.
I think the best way for you would be to write your own glue plugin that
just calls the main() method of the application after setting the system
properties.
--
Trygve
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Re: Build time classpath using my java plugin
Posted by TimHedger <Ti...@rbos.com>.
OK, so now I'm using the exec-plugin instead of my own code - great.
But I've lost the control I had over when the exec step happened.
I am using the plugin to generate SOAP wrappers for some Java code using
glue (themindelectric). This step involves running a Java class with
certain parameters and it creates various xml files and a directory
structure, ready for packing into a war for distribution.
My problem is this is happening every time I compile using maven. I've lost
any control over checking whether source is stale and thus the soap/exec
step if nothing's changed since my last build.
How can I get this control with the exec plugin?
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Re: Build time classpath using my java plugin
Posted by TimHedger <Ti...@rbos.com>.
Doh! (Thank you)
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Re: Build time classpath using my java plugin
Posted by Tim Kettler <ti...@udo.edu>.
replace <goal>exec</goal> with <goal>java</goal>
TimHedger schrieb:
> You're right - I did some unnecessary work! (I took my approach from the
> idlj plugin, that basically puts some wrapper stuff around running the main
> method on a Java class - I guess that was done that way for convenience
> rather than needing lots of config in the pom).
>
> Anyway, I've dumped my plugin (less code has to be better) and am now using
> the exec-maven-plugin. And I can get it to do exactly what I need stand
> alone - by invoking it explicitly:
>
> mvn exec:java
>
> will run the necessary Java class with all my arguments.
>
> But I want to attach this step to a phase so it is nicely included in my
> build cycle. So I took the approach I have taken with other pugins, but it
> doesn't seem to work here.
>
> Specifics - this is the plugin section of my pom.xml:
> <build>
> <plugins>
> <plugin>
> <groupId>org.codehaus.mojo</groupId>
> <artifactId>exec-maven-plugin</artifactId>
> <executions>
> <execution>
> <id>glue-processing</id>
> <phase>compile</phase>
> <goals>
> <goal>exec</goal>
> </goals>
> </execution>
> </executions>
> <configuration>
> <debug>true</debug>
> <executable>java</executable>
> <mainClass>electric.application.tools.NewApp</mainClass>
> <arguments>
> <argument>-Delectric.apphome=target/glue</argument>
> <argument>-Delectric.home=/apps/product/glue</argument>
> <argument>-h</argument>
> <argument>VentureVaRService</argument>
> </arguments>
> </configuration>
> </plugin>
> </plugins>
> </build>
>
> Here I've tried to attach the exec:java goal to the compile phase.
>
> When I invoke mvn exec:java, I get what I expect:
>
> : mvn exec:java
> [INFO] Scanning for projects...
> [INFO] Searching repository for plugin with prefix: 'exec'.
> [INFO]
> ----------------------------------------------------------------------------
> [INFO] Building Maven Quick Start Archetype
> [INFO] task-segment: [exec:java]
> [INFO]
> ----------------------------------------------------------------------------
> [INFO] Preparing exec:java
> [INFO] No goals needed for project - skipping
> [INFO] [exec:java]
> [DEPLOYMENT] creating application directory at
> /home/hedgert/maven/venvar/target/glue/VentureVaRService
> [DEPLOYMENT] copying application files from /apps/product/glue/common
> [DEPLOYMENT] adding application configuration URLs to config.xml
> [DEPLOYMENT] saving application configuration file
> [DEPLOYMENT] application has been successfully created
> [INFO]
> ------------------------------------------------------------------------
> [INFO] BUILD SUCCESSFUL
> [INFO]
> ------------------------------------------------------------------------
> [INFO] Total time: 8 seconds
> [INFO] Finished at: Tue Jul 11 18:47:37 BST 2006
> [INFO] Final Memory: 3M/8M
> [INFO]
> ------------------------------------------------------------------------
>
> (The DEPLOYMENT lines are the correct output from the Java class I'm
> running, and this output shows it has taken the arguments I defined in the
> pom).
>
> But if I try to use the compile phase instead:
>
> : mvn compile
> [INFO] Scanning for projects...
> [INFO] -------------------------------------------------------------------
> [INFO] Building Maven Quick Start Archetype
> [INFO] task-segment: [compile]
> [INFO] -------------------------------------------------------------------
> [INFO] [resources:resources]
> [INFO] Using default encoding to copy filtered resources.
> [INFO] [compiler:compile]
> [INFO] No sources to compile
> [INFO] [exec:exec {execution: glue-processing}]
> [INFO] Usage: java [-options] class [args...]
> [INFO] (to execute a class)
> [INFO] or java -jar [-options] jarfile [args...]
> [INFO] (to execute a jar file)
> [INFO]
> [INFO] where options include:
> [INFO] -d32
> [INFO] use a 32-bit data model if available
> [INFO] -d64
> [INFO] use a 64-bit data model if available
> (etc etc)
>
> In this case it seems to have invoked the plugin, but it has ignored all my
> arguments and simply run Java with no parameters. And yet the pom.xml file
> is unchanged between these two runs.
>
> So given the first one (mvn exec:java) works, I guess I'm doing something
> wrong with the way I'm trying to attach the plugin goal to the compile phase
> of the build.
>
> Can someone point out my mistake?
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Re: Build time classpath using my java plugin
Posted by TimHedger <Ti...@rbos.com>.
You're right - I did some unnecessary work! (I took my approach from the
idlj plugin, that basically puts some wrapper stuff around running the main
method on a Java class - I guess that was done that way for convenience
rather than needing lots of config in the pom).
Anyway, I've dumped my plugin (less code has to be better) and am now using
the exec-maven-plugin. And I can get it to do exactly what I need stand
alone - by invoking it explicitly:
mvn exec:java
will run the necessary Java class with all my arguments.
But I want to attach this step to a phase so it is nicely included in my
build cycle. So I took the approach I have taken with other pugins, but it
doesn't seem to work here.
Specifics - this is the plugin section of my pom.xml:
<build>
<plugins>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<executions>
<execution>
<id>glue-processing</id>
<phase>compile</phase>
<goals>
<goal>exec</goal>
</goals>
</execution>
</executions>
<configuration>
<debug>true</debug>
<executable>java</executable>
<mainClass>electric.application.tools.NewApp</mainClass>
<arguments>
<argument>-Delectric.apphome=target/glue</argument>
<argument>-Delectric.home=/apps/product/glue</argument>
<argument>-h</argument>
<argument>VentureVaRService</argument>
</arguments>
</configuration>
</plugin>
</plugins>
</build>
Here I've tried to attach the exec:java goal to the compile phase.
When I invoke mvn exec:java, I get what I expect:
: mvn exec:java
[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'exec'.
[INFO]
----------------------------------------------------------------------------
[INFO] Building Maven Quick Start Archetype
[INFO] task-segment: [exec:java]
[INFO]
----------------------------------------------------------------------------
[INFO] Preparing exec:java
[INFO] No goals needed for project - skipping
[INFO] [exec:java]
[DEPLOYMENT] creating application directory at
/home/hedgert/maven/venvar/target/glue/VentureVaRService
[DEPLOYMENT] copying application files from /apps/product/glue/common
[DEPLOYMENT] adding application configuration URLs to config.xml
[DEPLOYMENT] saving application configuration file
[DEPLOYMENT] application has been successfully created
[INFO]
------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO]
------------------------------------------------------------------------
[INFO] Total time: 8 seconds
[INFO] Finished at: Tue Jul 11 18:47:37 BST 2006
[INFO] Final Memory: 3M/8M
[INFO]
------------------------------------------------------------------------
(The DEPLOYMENT lines are the correct output from the Java class I'm
running, and this output shows it has taken the arguments I defined in the
pom).
But if I try to use the compile phase instead:
: mvn compile
[INFO] Scanning for projects...
[INFO] -------------------------------------------------------------------
[INFO] Building Maven Quick Start Archetype
[INFO] task-segment: [compile]
[INFO] -------------------------------------------------------------------
[INFO] [resources:resources]
[INFO] Using default encoding to copy filtered resources.
[INFO] [compiler:compile]
[INFO] No sources to compile
[INFO] [exec:exec {execution: glue-processing}]
[INFO] Usage: java [-options] class [args...]
[INFO] (to execute a class)
[INFO] or java -jar [-options] jarfile [args...]
[INFO] (to execute a jar file)
[INFO]
[INFO] where options include:
[INFO] -d32
[INFO] use a 32-bit data model if available
[INFO] -d64
[INFO] use a 64-bit data model if available
(etc etc)
In this case it seems to have invoked the plugin, but it has ignored all my
arguments and simply run Java with no parameters. And yet the pom.xml file
is unchanged between these two runs.
So given the first one (mvn exec:java) works, I guess I'm doing something
wrong with the way I'm trying to attach the plugin goal to the compile phase
of the build.
Can someone point out my mistake?
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Re: Build time classpath using my java plugin
Posted by Trygve Laugstøl <tr...@apache.org>.
TimHedger wrote:
> I've written a plugin (in Java) that explicitly invokes the main method of a
> Java class directly from within the jvm that maven is already running. My
> plugin is behaving/configured as I expect, but I have a classpath problem
> when control switches from my plugin code to the main method of the Java
> class it invokes.
Seems like you have implemented the exec-maven-plugin [1].
> I use the following method to print the classpath before I invoke the main
> method on my target class:
> project.getCompileClasspathElements();
>
> (where project is MavenProject)
>
> And I get the list of jars I expect, including:
> /home/hedgert/.m2/repository/javax/servlet/servlet-api/2.4/servlet-api-2.4.jar
>
> which is the copy of javax.servlet that I have in my local maven repository.
> Great - so far so good.
>
> I invoke the main method of my target class and the code runs and then falls
> over with a:
> java.lang.NoClassDefFoundError: javax/servlet/ServletException
>
> If I check the contents of my servlet-api-2.4.jar:
> : jar -tf
> /home/hedgert/.m2/repository/javax/servlet/servlet-api/2.4/servlet-api-2.4.jar
> |grep ServletException
> javax/servlet/ServletException.class
>
> The missing class is indeed in the jar that is on the classpath.
>
> So presumably the classpath I'm getting back from:
> project.getCompileClasspathElements();
>
> is not actually the classpath in operation when I invoke the main method on
> my class from within a running JVM.
>
> So my question is: maven has nicely worked out the classpath I need (using
> the dependencies in my pom.xml file for my target project, rather than my
> plugin), how do I get this classpath be active in the running JVM?
You don't. The classpath that the plugin is running in contains all
dependencies of the plugin, not the project. If you want to do something
with the project's classpath you will have to create a classloader from
the list you're referring to.
[1]: http://mojo.codehaus.org/exec-maven-plugin/
--
Trygve
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