Custom JaCoCo Gradle Plugin - exclude files in report - groovy

Question

I'm new to Gradle and Groovy.
I have something like this in my build.gradle file:
jacocoTestReport {
afterEvaluate {
classDirectories.setFrom(files(classDirectories.files.collect {
fileTree(dir: it, exclude: ['aaa/bbb.*', 'ccc/ddd/*',])
}))
}
}
Now, I need this in my custom plugin. But I'm not sure how to set these excludes to it.
I have something like this:
project.afterEvaluate { p ->
def reportTask = project.tasks.findByName('jacocoTestReport') as JacocoReport
reportTask.classDirectories.setFrom(reportTask.classDirectories.files.) // Now what?
}
And I'm stuck here. Can you help me sort this out, please?
EDIT1:
I tried to solve it using patternSet.
println '----------------BEFORE REPORT----------------------'
def patternSet = new PatternSet()
def filesAsString = reportTask.classDirectories.files.collect { file ->
file.path
}
patternSet.setIncludes(filesAsString)
patternSet.setExcludes(['aaa/bbb.*', 'ccc/ddd/*'])
def excludeFiles = reportTask.classDirectories.asFileTree.matching(patternSet).files
println filesAsString
println excludeFiles
def files = reportTask.classDirectories.asFileTree.minus(excludeFiles)
reportTask.classDirectories.setFrom(files)
println '----------------AFTER REPORT----------------------'
println reportTask.classDirectories.files
Result is not what I expected:
----------------BEFORE REPORT----------------------
[aaa\bbb\build\classes\java\main, aaa\bbb\build\classes\groovy\main, aaa\bbb\build\resources\main]
[]
----------------AFTER REPORT----------------------
[]
No exclude directories at all.

Answer 1

So, I somehow solved it.
def ex = ['aaa/bbb/*','ccc/ddd.*','eee/fff/*']
def ft = reportTask.classDirectories.asFileTree.matching {
ex.each {
exclude it
}
}
Don't ask me how Gradle wraps this since it's not a Groovy syntax, but it works.
My opinion is that Gradle somehow implements AntlrTask as a pattern matcher since it implements interface 'PatternFilterable' and documentation mentions Ant. I tried to solve it in pure Groovy using PatternSet which is another class implementing PatternFilterable but I haven't succeded.
But the simple exclude 'aaa/bbb/*' works OK. It doesn't take list so I had to do it using forEach cycle. Maybe there is more simple and elegant way and I'll try to play with it but this solution is good enough.