So there I was, just a hackin' and a codin' a mod for Minecraft in Eclipse. And at the end, there's a bunch of stuff to do: Run a couple special external tools, relocate a bunch of files into a new folder tree, and then zip them up, add comments to the zip file, and so on. And I had a pretty cool batch file to do all that. Then someone showed me ANT, and I'm sold.

Ant does all the stuff I was doing, but much more elegantly. The tool uses an xml file, usually called build.xml, and it looks like this:

<project>
   <target>
       <!-- do some stuff -->
   </target>
 
   <target>
      <!-- do some other stuff -->
   </target>
</project>

The build.xml that I made for my Minecraft modding endeavors looks like so:[spoiler]

<?xml version="1.0" encoding="UTF-8"?>
<!-- ======================================================================
     Master Build file designed to work for all my minecraft mod projects
    
     Variables passed in from Eclipse environment:
     {project_name}

     ====================================================================== -->

<project name="${project_name}" default="all" basedir="D:/docs/prog/minecraft">

<!-- Manager task, executes all other tasks -->
<target name="all" description="default master task"
   depends="initialize, clean, stage, recompile, reobfuscate, zip, cleanup">
   <echo message="Finished building ${distribution}"/>
</target>

<!-- Debugging task, skips recompile/reobfuscate -->
<target name="debug"
   depends="initialize, clean, stage, zip, cleanup">
   <echo message="Rebuilt ${distribution}"/>
</target>

<!-- Initialize task -->
<target name="initialize">
   <echo message="Building ${project_name}"/>
   <property name="version" value="Pre-Alpha"/>

   <!-- Files and Folders -->
   <property name="MOD"         location="${basedir}/mods/${project_name}"/>
   <property name="anglewyrm" location="${basedir}/../anglewyrm"/>
   <property name="MCP"         location="${basedir}/MCP152"/>
   <property name="staging_area" location="${MCP}/src/minecraft/mods/${project_name}"/>
   <property name="reobf"     location="${MCP}/reobf/minecraft"/>
   <property name="python"     location="${MCP}/runtime/bin/python/python_mcp.exe"/>
   <tstamp>
      <format property="dateStamp" pattern="dd-MMM-yyyy"/>
   </tstamp>
   <property name="distribution" location="${basedir}/distribution/${project_name}-${dateStamp}.zip"/>
</target>

<!-- Clean -->
<target name="clean">
   <echo message="Preparing empty staging area"/>
   <delete dir="${staging_area}"/>
   <delete file="${distribution}"/>
   <mkdir dir="${staging_area}"/>
</target>

<!-- Stage source -->
<target name="stage">
   <echo message="Staging source to ${staging_area}"/>
   <filter token="VERSION" value="${version}"/>
   <filter token="RELEASE_DATE" value="${dateStamp}"/>
   <copy todir="${staging_area}" filtering="true">
      <fileset dir="${MOD}" excludes="textures/**"/>
   </copy>
   <copy todir="${staging_area}/textures" filtering="false">
      <fileset dir="${MOD}/textures" />
   </copy>
   <copy todir="${staging_area}/../..">
      <fileset file="${staging_area}/mcmod.info"/>
   </copy>
   <delete file="${staging_area}/mcmod.info"/>
</target>

<!-- Run recompile -->
<target name="recompile" description="MCP recompile" >
   <exec executable="${python}" dir="${MCP}" >
      <arg value="runtime/recompile.py" />
      <arg value="%*" />
   </exec>
</target>

<!-- Run reobfuscate -->
<target name="reobfuscate" description="MCP reobfuscate" >
   <exec executable="${python}" dir="${MCP}" >
      <arg value="runtime/reobfuscate.py" />
      <arg value="%*" />
   </exec>
</target>

<!-- Zip -->
<target name="zip" description="Zip up the mod">
   <echo message="Creating ${distribution}" />
   <zip destfile="${distribution}">
      <zipfileset dir="${reobf}" />
      <zipfileset dir="${staging_area}/textures" prefix="mods/${project_name}/textures" />
      <zipfileset dir="${staging_area}/../.." includes="mcmod.info" />
   </zip>
</target>

<!-- Cleanup -->
<target name="cleanup">
   <echo message="Removing temporary files"/>
   <!-- <delete dir="${staging_area}"/> -->
</target>

</project>

[/spoiler]

It can do advanced stuff, like substituting a token string during a copy operation. Within my source files is @VERSION@, but when copied by the build.xml, that string gets replaced.