What is the equivalent of an Ant taskdef in Gradle? - gradle

Question

I've been struggling with this for a day and a half or so. I'm trying to replicate the following Ant concept in Gradle:
<target name="test">
...
<runexe name="<filename> params="<params>" />
...
</target>
where runexe is declared elsewhere as
<macrodef name="runexe" >
...
</macrodef>
and might also be a taskdef or a scriptdef i.e. I'd like to be able to call a reusable, pre-defined block of code and pass it the necessary parameters from within Gradle tasks. I've tried many things. I can create a task that runs the exe without any trouble:
task runexe(type: Exec){
commandLine 'cmd', '/c', 'dir', '/B'
}
task test(dependsOn: 'runexe') {
runexe {
commandLine 'cmd', '/c', 'dir', '/N', 'e:\\utilities\\'
}
}
test << {
println "Testing..."
// I want to call runexe here.
...
}
and use dependsOn to have it run. However this doesn't allow me to run runexe precisely when I need to. I've experimented extensively with executable, args and commandLine. I've played around with exec and tried several different variations found here and around the 'net. I've also been working with the free books available from the Gradle site.
What I need to do is read a list of files from a directory and pass each file to the application with some other arguments. The list of files won't be known until execution time i.e. until the script reads them, the list can vary and the call needs to be made repeatedly.
My best option currently appears to be what I found here, which may be fine, but it just seems that there should be a better way. I understand that tasks are meant to be called once and that you can't call a task from within another task or pass one parameters but I'd dearly like to know what the correct approach to this is in Gradle. I'm hoping that one of the Gradle designers might be kind enough to enlighten me as this is a question asked frequently all over the web and I'm yet to find a clear answer or a solution that I can make work.

Answer 1

If your task needs to read file names, then I suggest to use the provided API instead of executing commands. Also using exec will make it OS specific, therefore not necessarily portable on different OS.
Here's how to do it:
task hello {
doLast {
def tree = fileTree(dir: '/tmp/test/txt')
def array = []
tree.each {
array << it
print "${it.getName()} added to array!\n"
}
}
}

Answer 2

I ultimately went with this, mentioned above. I have exec {} working well in several places and it seems to be the best option for this use case.
To please an overzealous moderator, that means this:
def doMyThing(String target) {
exec {
executable "something.sh"
args "-t", target
}
}
as mentioned above. This provides the same ultimate functionality.