Question

I have a directory of files for which I’d like to do “in-place” string filtering using Apache Ant (version 1.7.1 on Linux).

For example, suppose that in directory mydir I have files foo, bar, and baz. Further suppose that all occurences of the regular expression OLD([0-9]) should be changed to NEW\1, e.g. OLD2 → NEW2. (Note that the replace Ant task won’t work because it does not support regular expression filtering.)

This test situation can be created with the following Bash commands (ant will be run in the current directory, i.e. mydir‘s parent directory):

mkdir mydir
for FILE in foo bar baz ; do echo "A OLD1 B OLD2 C OLD3" > mydir/${FILE} ; done

Here is my first attempt to do the filtering with Ant:

<?xml version="1.0"?>
<project name="filter" default="filter">
    <target name="filter">
        <move todir="mydir">
            <fileset dir="mydir"/>
            <filterchain>
                <tokenfilter>
                    <replaceregex pattern="OLD([0-9])" replace="NEW\1" flags="g"/>
                </tokenfilter>
            </filterchain>
        </move>
    </target>
</project>

Running this first Ant script has no effect on the files in mydir. The overwrite parameter is true by default with the move Ant task. I even fiddled with the granularity setting, but that didn’t help.

Here’s my second attempt, which “works,” but is slightly annoying because of temporary file creation. This version filters the content properly by moving the content to files with a filtered suffix, then the filtered content is “moved back” with original filenames:

<?xml version="1.0"?>
<project name="filter" default="filter">
    <target name="filter">
        <move todir="mydir">
            <globmapper from="*" to="*.filtered"/>
            <fileset dir="mydir"/>
            <filterchain>
                <tokenfilter>
                    <replaceregex pattern="OLD([0-9])" replace="NEW\1" flags="g"/>
                </tokenfilter>
            </filterchain>
        </move>
        <move todir="mydir">
            <globmapper from="*.filtered" to="*"/>
            <fileset dir="mydir"/>
        </move>
    </target>
</project>

Can the first attempt (without temporary files) be made to work?

Answer 1

See the replace task:

<replace 
   dir="mydir" 
   includes="foo, bar, baz">
   <replacefilter token="OLD" value="NEW" />
</replace>

or the replaceregexp task:

<replaceregexp
    file="${src}/build.properties"
    match="OldProperty=(.*)"
    replace="NewProperty=\1"
    byline="true"/>