run a class from a jar using ant

Here’s how you can run any class from a jar file, using ant:

<java classname="my.class">
  <classpath>
     <pathelement location="my.jar"/>
  </classpath>
</java>

increase ant memory

Recently, I had to increase the memory ant was using. This is what I used:

set ANT_OPTS=-Xmx256m

using ruby from ant

An example on how you could use a fileset from a ruby script task:

<script language="ruby" classpathref="jruby_classpath">
	task = $project.createDataType("fileset")
	task.case_sensitive = false
	task.setDir java.io.File.new($basedir)
	task.setIncludes("**/*.*")
	task.setExcludes("**/*test*/**")
	scanner = task.getDirectoryScanner($project)
	scanner.getIncludedFiles.each {|f| puts f}
</script>

This snippet will include every file in the basedir, except those containing the string test.

getting a basename from a path using ant

If you have a path written in a file, and you’d like to get a basename from it, like in the following example:

/this/is/my/path.txt

after you run this target, you will have only path.txt. Here’s the code that makes that possible:

<target name="rgx" description="basename equivalent">
	<replaceregexp file="a.txt" match="(.*/)|(.*\\)" replace="" byline="true"/>
</target>

replacing a windows path with a unix one using ant

If for some reason ant interprets your backslashes and you need slashes to make your thing work, here’s a snippet that will convert your windows style path to a unix style one :

1. <target name="replace-path-example">
2.   <property name="WIN_PATH" refid="some.path"/>
3.   <echo message="${WIN_PATH}" file="temp.file"/>
4.   <replace file="temp.file" token="\" value="/"/>
5.   <loadfile srcfile="temp.file" property="UNIX_PATH"/>
6.   <echo message="path is ${UNIX_PATH}"/>
7.   <delete file="temp.file"/>
8. </target>

some ant tips

Here are some tips I can offer you which will most certainly make your life easier :

1. use the basedir variable instead of ., ant’s consideration of “.” is very strange
2. use the ANT_OPTS environment variable to set the java.library.path

If I had known these tips, I would have saved several hours of work.