Ant read files in a directory and regex - ant

Question

I am trying to read the names of a set of files in a directory and apply regex to those names and obtain a list with comma seperated values. The names of the files are in the format of build_level1_D1.properties, build_level1.D2.properties, build_level2.D1.properties etc...
I need to read all the file names and apply regex and parse the names to get level1_D1, level1_D2, level2_D1 etc.. I need it in the format of property name="build.levels" value="level1_D1,level1_D2,level2_D1" This is what i tried. Need some pointers and help.
<target name="build-levels-all">
<for param="program">
<path><fileset dir="${root.build.path}/build" includes="*"/>
</path>
<sequential>
<propertyregex override="yes" property="file" input="#{program}" regexp="build\_([^\.]*)" select="\1" />
<echo>${file}</echo>
</sequential>
</for>
<echo>${program}</echo>
<-- This prints the files regexed Level1_D1, level2_D2 etc....But i need to capture it in the format of <property name="build.levels" value="level1_D1,level1_D2,level2_D1" /> -->
</target>

Answer 1

Try using an embedded scripting language, like groovy, to do this kind of complex logic.
<target name="process-files">
<taskdef name="groovy" classname="org.codehaus.groovy.ant.Groovy"/>
<groovy>
def list = []
new File('build').eachFile() {
def matcher = it.name =~ /(build_level\d_D\d).properties/
list.add matcher[0][1]
}
properties."build.levels" = list.join(",")
</groovy>
</target>
<target name="doSomething" depends="process-files">
<echo>${build.levels}</echo>
</target>
Just like ant-contrib, groovy needs an additional jar. I normally include a "bootstrap" target to install this:
<target name="bootstrap">
<mkdir dir="${user.home}/.ant/lib"/>
<get dest="${user.home}/.ant/lib/groovy-all.jar" src="http://search.maven.org/remotecontent?filepath=org/codehaus/groovy/groovy-all/2.1.6/groovy-all-2.1.6.jar"/>
</target>