Gradle script for querydsl-apt processor with separate classpath

querydsl.gradle

// apply plugin: 'idea'

sourceSets {
    generated.java
    main.java.srcDirs += generated.java.srcDirs
}

configurations {
    querydslapt
}

dependencies {
    querydslapt "com.querydsl:querydsl-apt:$querydslVersion"
}

task querydsl(type: JavaCompile, group: 'build', description: 'Generate the QueryDSL query types') {
    source = sourceSets.main.java
    classpath = configurations.compile + configurations.querydslapt
    options.compilerArgs = [
            '-proc:only', //only annotations
            '-processor', 'com.querydsl.apt.morphia.MorphiaAnnotationProcessor'
    ]
    destinationDir = sourceSets.generated.java.srcDirs.iterator().next()
}

compileJava.dependsOn querydsl

clean {
    delete sourceSets.generated.java.srcDirs
}

Thanks a lot!
It was the only hint I could find on integrating custom annotation processor!