Using Apache Ant for Testing DELPH-IN Tools and Resources

(UlrichSchaefer)

A short description of SProUTomat can be found here. Here is the LREC-06 paper.

I start with a short description of ant I copied from http://ant.apache.org :

Apache Ant is a Java-based build tool. In theory, it is kind of like Make, but without Make’s wrinkles.

Why another build tool when there is already make, gnumake, nmake, jam, and others? Because all those tools have limitations that Ant’s original author couldn’t live with when developing software across multiple platforms. Make-like tools are inherently shell-based – they evaluate a set of dependencies, then execute commands not unlike what you would issue in a shell. This means that you can easily extend these tools by using or writing any program for the OS that you are working on. However, this also means that you limit yourself to the OS, or at least the OS type such as Unix, that you are working on.

Makefiles are inherently evil as well. Anybody who has worked on them for any time has run into the dreaded tab problem. “Is my command not executing because I have a space in front of my tab!!!” said the original author of Ant way too many times. Tools like Jam took care of this to a great degree, but still have yet another format to use and remember.

Ant is different. Instead of a model where it is extended with shell-based commands, Ant is extended using Java classes. Instead of writing shell commands, the configuration files are XML-based, calling out a target tree where various tasks get executed. Each task is run by an object that implements a particular Task interface.

Granted, this removes some of the expressive power that is inherent by being able to construct a shell command such as `find . -name foo -exec rm {}`, but it gives you the ability to be cross platform – to work anywhere and everywhere. And hey, if you really need to execute a shell command, Ant has an <exec> task that allows different commands to be executed based on the OS that it is executing on.

The only prerequisite for running ant is a Java JRE (JDK if Java compilation is required), and via Java, the most important platforms are supported, like Windows, Linux, Solaris, Mac OS etc.

Advantages I see in the DELPH-IN context:

  • platform-independent (except for some very special external tasks)
  • widely used, e.g. standard in Eclipse
  • powerful patternset, fileset, filemapper, filterset, filterchain mechanism
  • user-definable tasks (java class)
  • external binaries can be called (exec)
  • support for BSF subshells
  • plugin-mechanism for third-party extensions
  • many usually platform-dependent tools can be called platform independently:
    • zip, tar, gzip, bzip, jar, javadoc, SQL, SMTP, file/dir operations, ftp, perforce, scp, sshexec, telnet, checksum, buildnumber
  • pre-defined external platform-dependent tasks: rpm, cab etc.
  • built-in integration of XSLT and XML validation
  • parallelism (using Java threads), sequence, waitfor
  • configuration (e.g. default values for properties/variables) via property files

Disadvantages:

  • variables are write-once only (first setting wins e.g. command line args overwrite internal defaults; i.e. similar to XSLT variables)
  • no <if> construct (could be added using a plug-in)
  • svn support still only via plug-in (will probably be integrated in the near future)

BTW Heart of Gold already uses a (quite) small ant build script for compiling, starting, generating stylsheets etc.: file hog/build.xml in the source tree

Last update: 2011-10-09 by anonymous [edit]