Today I wanted to find out, using Ant, if any of a set of files existed. Based on that information, I would conditionally execute a target. Well, really I needed to solve a problem in Maven, but an Ant solution would plug in just fine. Here’s what I came up with:

<project name="test" default="test" basedir=".">
    <target name="test">
        <delete file="target\dir\status.file"/>
        <copy todir="target\dir">
            <fileset dir="target\dir" includes="*.xml"/>
            <mapper type="merge" to="status.file"/>
        <available property="test.any" value="true" file="target\dir\status.file"/>
        <property name="test.any" value="false"/>
        <echo>any.xml: ${test.any}</echo>

That seems to work. The side effect is that one file is duplicated exactly, but only one.