Howto Auto increment version numbers in ANT

I have been playing around with Ivy for some dependency management goodness to implement in my project. So far Ivy looks quite good (though I am still trying to figure out how to use configurations in my project) and also playing around with setting up my own software repository.

When looking at the depenence sample in Ivy, came across a part where the version number gets updated as the module is published to the repositoriesthought I just post a more generic version that makes it as a Ant target.This would be useful when dealing with automated builds or when using Ivy to post to a in-house repository.

<target name="increment">
<propertyfile file="build.properties">
<entry key="build.number" type="int" operation="+" default="0"/>
</propertyfile>
<property file="build.properties"/>
<echo message="Build number is ${build.number""/>
</target>

What the above target does is that it looks for a <propertyfile> and looks for the build.number property. If both are not present it will create the file and increment the number. So if you do not have the file/property you start off with build number 1.

But the properties are not loaded in ant, that's why you need to load the property file using <property>, then you can reference build.number using normal ant properties notation.

You can test this in an ant script by calling ant increment.

So to use it to make a jar file, you probably would do something like

<jar destfile="${build.dir}/${ant.project.name}-${major}.${minor}.${build.number}.jar">....</jar>