Breaking Version Inertia: Ant: import and macrodef

Mon, 14 Apr 2008 17:06:23 GMT

I've been using Ant since the very early days. ("Tomcat is built with Ant. What is Ant?" Remember those days?) Since my use of ant does not usually involve anything esoteric, I have fallen victim to version inertia. Ant 1.4, 1.5, 1.6, 1.7 came out over the years, and I didn't much glance at the release notes.

Meanwhile, some of my build.xml files has grown organically. Since the code is modularized with a nice "B depends on A, C depends on B, etc..." structure, the build.xml reflects that with targets like "compile-A", "compile-A-test", "run-A-test", "compile-B", "compile-B-test", "run-B-test", ..., each with their own classpath definition.

And as we added modules, we copy and pasted big chunks of Ant code, bloating the build file.

This become unbearable recently. And I looked for ways to make the build file manageable again. That's when I found the two new features of Ant: import and macrodef. Both are available in the latest Ant 1.7.0 release.

I won't bore you with the details of how these two tasks work. But it did allow me to break my build file into a

template-build.xml

which contains a set of macro definitions, and a bunch of

A-build.xml
B-build.xml
...

files each importing template-build.xml and instantiate the set of targets for a module. The build.xml then imports all the A-build.xml, ... files and use all the targets in a systematical way.

If you are using Ant, import and macrodef are your friends, just like if you are using C, #import and #define are your friends.

Thursday Ant Quiz

Thu, 13 Mar 2008 18:27:36 GMT

I'm tearing my hairs out, so I think you should do the same. I'll make you, as a matter of fact, by way of a Thursday Ant quiz:

The Set Up: There are two files in the current directory: Foo.java and Foo.class.

Q: Write an Apache Ant 1.7.0 compatible build.xml file in the directory, which, when invoked with the ant, removes Foo.class but not Foo.java. You cannot use the word "Foo" in the build file.

No Googling, no peeking into the online Ant manual or any Ant books.

Weiqi Gao's Observations - ant tag

Breaking Version Inertia: Ant: import and macrodef

Thursday Ant Quiz