How to use maven to publish multiple artifacts of an ivy project(with multiple modules) to a maven repository(nexus) - maven

Question

I'm working on a complex multi-module open source ivy project, which has ant's build.xml at the top level to kick off each ivy module's build. But the goal here is not to modify the original build scripts(both ivy.xml and build.xml), and using maven as an outer layer to kick off ant build, and then fetch the built results and publish them to nexus server.
The difficulty here is that, the built artifacts here are multiple jars, and we need to publish all these jars to nexus server with maven. Since one pom.xml only maps one maven artifafct, and in this case multiple artifacts are build not through maven but ivy. So I wonder if there's a feasible way to achieve my goal.
Currently, in the top level pom.xml, I'm using maven-antrun-plugin to invoke build.xml on top level, and using build-helper-maven-plugin to attache artifacts, but it doesont' work.

Answer 1

Currently I'm working on a similar task to yours. We have a huge, full of legacy system with whole build written in ant. That is how we handle this task:
No matter what, you will have to accept it, maven = jar per artifact (well, you can use attachments with qualifiers, but it's a real abuse and highly NOT recommended). It has it's philosophy after it: in the end of the day your system consists of (as you said yourself) modules, so each module has to have it's version, sources and (most important) the dependencies to other modules.
To reuse the existing ant code you can look on the antrun plugin. What we did, is "simply" separated all the common build code (i.e generators execution, attachments creation, assemblies and so on) to parent poms that are of type "pom". Then we execute the relevant targets simply by activating properties in children poms. Here is an example
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-antrun-plugin</artifactId>
<version>1.7</version>
<executions>
<execution>
<id>EXECUTION_NAME</id>
<phase>generate-sources</phase>
<goals>
<goal>run</goal>
</goals>
<configuration>
<target if="EXECUTION_TRIGGER_PROPERTY">
<taskdef resource="net/sf/antcontrib/antlib.xml"/>
</target>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
And in the child pom we simply define
<properties>
<EXECUTION_TRIGGER_PROPERTY>true</EXECUTION_TRIGGER_PROPERTY>
</properties>
remember to look at maven lifecycle guide to choose the proper phase for your execution.
Don't forget that you can use maven plugins to make things easier. E.g instead of running <javac> task in ant, breaking to artifacts with jar type do all the compile for you. You can also find plugins that generate javadoc, jaxws and so on.
As you can see it's not that simple to make your system work with maven. It will require you to rethink how your build works. On the other hand the ability to see and understand your dependencies, the ease of working in modern IDE's, binary repositories and so on are worth it in most of the cases.