Ant-javac doesn't see dependencies from Gradle - ant

Question

I'm trying to migrate from ant to gradle. First phase of this is to move all dependecies to gradle.build and still build war via ant.
In ant building task looks like that:
<fileset id="project-libraries" dir="${project.libs.path}">
<include name="*jar"/>
</fileset>
<path id="master-classpath">
<fileset refid="project-libraries"/>
<fileset refid="tomcat"/>
<fileset refid="hibernate-tools"/>
<fileset refid="findbug"/>
<pathelement path="${build.dir}"/>
</path>
<target name="build" description="Build the application">
<javac destdir="${build.dir}" target="${javac.version}" source="${javac.version}" nowarn="true" deprecation="false" optimize="false" failonerror="true" encoding="utf-8" debug="on">
<src refid="src.dir.set"/>
<classpath refid="master-classpath${master-classpath-version}"/>
<compilerarg value="-Xlint:-unchecked"/>
</javac>
</target>
In Gradle I'm importing build.xml with this code:
ant.importBuild('build.xml') { antTargetName ->
'ant_' + antTargetName
}
The problem is that ant task (./gradlew ant_build) doesn't have dependencies from Gradle (dependencies { ... }). How can I put them into classpath (without modifying ant build)?

Answer 1

You can do the following to add the dependencies to the project's AntBuilder instance:
task antClasspathSetter {
doLast {
def antClassLoader = org.apache.tools.ant.Project.class.classLoader
configurations.compile.each { File f ->
antClassLoader.addURL(f.toURI().toURL())
}
}
}
ant_build.dependsOn antClasspathSetter
However, this is a 'hacky' solution.
Using taskdef is a better solution, if the ant build script can be moved to a separate ant task file. In that case, you can do the following:
ant.taskdef(name: 'myAntTask',
classname: 'my.ant.Task',
classpath: configurations.compile.asPath)

Answer 2

I used a copy task to put all of my gradle dependencies into a {libs} folder that I declared on my ant master-classpath.
//add property
<property name="lib.dir" value="${basedir}/lib" /></pre>
//tell ANT to put all jars in folder on classpath
<path id="master-classpath">
<fileset dir="${lib.dir}">
<include name="**/*.jar" />
</fileset>
....
</path>
// copy task goes in your build.gradle file
task copyGradleDependenciesInAntFolder(type: Copy) {
from configurations.compile
into 'lib'
}
// make sure to run it before your {ant_build} target
{ant_build}.dependsOn copyGradleDependenciesInAntFolder