Ant: Find the path of a file in a directory - file

Question

I want to find the path of a file in a directory (similar to unix 'find' command or the 'which' command, but I need it to work platform-independent) and save it as a property.
Tried to use the whichresource ant task, but it doesn't do the trick (I think it's only good for looking inside jar files).
I would prefer if it would be pure ant and not to write my own task or use a 3rd-party extension.
Notice that there might be several instances of a file by that name in the path - I want it to only return the first instance (or at least I want to be able to choose only one).
Any suggestions?

Answer 1

One possibility is to use the first resource selector. For example to find a file called a.jar somewhere under directory jars:
<first id="first">
<fileset dir="jars" includes="**/a.jar" />
</first>
<echo message="${toString:first}" />
If there are no matching files nothing will be echoed, otherwise you'll get the path to the first match.

Answer 2

Here is an example which selects the first matching file. The logic is as follows:
find all matches using a fileset.
using pathconvert, store the result in a property, separating each matching file with line separator.
use a head filter to match the first matching file.
The functionality is encapsulated in a macrodef for reusability.
<project default="test">
<target name="test">
<find dir="test" name="*" property="match.1"/>
<echo message="found: ${match.1}"/>
<find dir="test" name="*.html" property="match.2"/>
<echo message="found: ${match.2}"/>
</target>
<macrodef name="find">
<attribute name="dir"/>
<attribute name="name"/>
<attribute name="property"/>
<sequential>
<pathconvert property="#{property}.matches" pathsep="${line.separator}">
<fileset dir="#{dir}">
<include name="#{name}"/>
</fileset>
</pathconvert>
<loadresource property="#{property}">
<string value="${#{property}.matches}"/>
<filterchain>
<headfilter lines="1"/>
</filterchain>
</loadresource>
</sequential>
</macrodef>
</project>

Answer 3

I created a macro based on martin-clayton's answer.
sample project with macro and a property file that is read from the found file
<?xml version="1.0" encoding="utf-8"?>
<project name="test properties file read" default="info">
<macrodef name="searchfile">
<attribute name="file" />
<attribute name="path" default="custom,." />
<attribute name="name" />
<sequential>
<first id="#{name}">
<multirootfileset basedirs="#{path}" includes="#{file}" erroronmissingdir="false" />
</first>
<property name="#{name}" value="${toString:#{name}}" />
</sequential>
</macrodef>
<searchfile name="custom.properties.file" file="config.properties" />
<property file="${custom.properties.file}" />
<target name="info" >
<echo>
origin ${config.origin}
</echo>
</target>