How to execute ant jar from maven-antrun-plugin

Question

We are using Maven in combination with an Ant build.xml file for our buids.

The maven-antrun-plugin looks like this:

<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-antrun-plugin</artifactId>
  <!-- Version 1.8 uses Ant 1.9.4 -->
  <version>1.8</version>
  <executions>
    <execution>
      <id>Compile sources</id>
      <phase>compile</phase>
      <goals>
        <goal>run</goal>
      </goals>
      <configuration>
        <target>
          <mkdir dir="${temp.dir}"/>
          <mkdir dir="${dist.dir}"/>
          <exec dir="${project.basedir}" executable="${ant.exec}" failonerror="true">
            <arg
              line="-f xlatedb.ant.xml -DDLC ${dlc} -lib ${lib.dir}
                -Dtarget.dir ${target.dir}
                -Ddist.dir ${dist.dir}
                -Dtemp.dir ${temp.dir}
                -Dproject.version ${project.version} "/>
          </exec>
        </target>
      </configuration>
    </execution>
  </executions>
</plugin>

The maven-antrun-plugin uses Ant 1.9.4 internally. Is there a way to replace the dependency to ${ant.exec} with a call to that internal ant jar?

Now we pass the ant.exec to the mvn command. Using the ant task doesn't work because we also need to pass the -lib to ant. (the lib folder contains all of the downloaded dependencies).

The advantage of using this ant.exec approach is that we can use ant 1.10.5. I could however specify ant 1.10.5 in the dependencies and get that jar downloaded to the lib folder... But instead of starting the ant.bat file I would need a way to launch ant with that 1.10.5 jar.

Answer 1

You could call ant main class through the exec:java goal

pom.xml

<properties>        
    <target.dir>theTargetDirectory</target.dir>
</properties>
<build>
    <plugins>
        <plugin>
            <groupId>org.codehaus.mojo</groupId>
            <artifactId>exec-maven-plugin</artifactId>
            <version>1.6.0</version>
            <executions>
                <execution>
                    <phase>compile</phase>
                    <goals>
                        <goal>java</goal>
                    </goals>
                </execution>
            </executions>
            <configuration>
                <mainClass>org.apache.tools.ant.launch.Launcher</mainClass>
                <arguments>-f,xlatedb.ant.xml</arguments>
                <systemProperties>
                    <systemProperty>
                        <key>target.dir</key>
                        <value>${target.dir}</value>
                    </systemProperty>
                </systemProperties>
            </configuration>
        </plugin>
    </plugins>
</build>
<dependencies>
    <dependency>
        <groupId>org.apache.ant</groupId>
        <artifactId>ant</artifactId>
        <version>1.10.5</version>
        <scope>compile</scope>
    </dependency>
</dependencies>

xlatedb.ant.xml

<project default="print-version">
    <target name="print-version">
        <echo>${ant.version}</echo>
        <echo>${target.dir}</echo>
    </target>
</project>

mvn compile

Output:

--- exec-maven-plugin:1.6.0:java (default) @ stack-55711525-maven-antexec ---
Buildfile: /xyz/project/xlatedb.ant.xml
print-version:
[echo] Apache Ant(TM) version 1.10.5 compiled on July 10 2018
[echo] theTargetDirectory
BUILD SUCCESSFUL
Total time: 0 seconds

---

NOTE: If you want to make maven classpath available to ant during jar , I guess you can run copy-dependencies plugin early enough in the lifecycle, and then provide the dependencies output directory as classpath to ant.

e.g.

<path id="class.path">
  <fileset dir="target">
    <include name="copied-dependencies-dir/*.jar" />
  </fileset>
</path>