How do I use a patternset to filter a list of files?

Question

This seems like something that should be obvious, but I don't think it is. Given:

a space-delimited list of files (or comma-delimited, etc.)
a <patternset> of whitelisted patterns

How do I come up with a <fileset> that contains all of the files in the list that match the whitelisted pattern?

Getting a list of files from the list is easy enough:

<patternset id="the-patternset" includes="${list.of.files}" />
<fileset id="the-fileset" dir="${basedir}">
    <patternset refid="the-patternset" />
</fileset>
<pathconvert pathsep="${line.separator}" property="the-filelist" refid="the-fileset"/>
<echo>fileset: ${the-filelist}</echo>

…will happily produce a fileset with all of the files in ${list.of.files}. But adding a filter of sorts:

<patternset id="the-filter">
    <include name="includeme/**/*.java" />
    <exclude name="excludeme/**/*.java" />
</patternset>

<patternset id="the-patternset" includes="${list.of.files}" />
<fileset id="the-fileset" dir="${basedir}">
    <patternset refid="the-patternset" />
    <patternset refid="the-filter" />
</fileset>
<pathconvert pathsep="${line.separator}" property="the-filelist" refid="the-fileset"/>
<echo>fileset: ${the-filelist}</echo>

…will list a union of the patternsets—i.e., all files that match either the-filter or the-patternset.

How do I produce a fileset containing files that are in ${list.of.files} and match the-patternset?

martin clayton martin clayton · Accepted Answer · 2013-02-06T21:55:43

Here's a potted example. Create two filesets (or perhaps filelists) one from each of your patternsets. I'll just use fixed lists here:

<property name="list.1" value="a,b,c" />
<property name="list.2" value="b,c,d" />

<fileset dir="." id="set.1" includes="${list.1}" />
<fileset dir="." id="set.2" includes="${list.2}" />

Then use the <intersect> resource collection to get the required 'overlap' set:

<intersect id="intersect">
    <resources refid="set.1"/>
    <resources refid="set.2"/>
</intersect>

Most Ant tasks will allow you to use a resource collection in place of a simple fileset.

How do I use a patternset to filter a list of files?

1 Answers