Breaking change in calling Groovy on 1.8 upgrade

I've been bitten by this a couple of times now, so for anyone else's benefit: If you have a bat file that calls a groovy program, you may notice surprising behaviour after an upgrade from 1.7.x to 1.8.x (I went from 1.7.4 to 1.8.4).

If your bat file looks something like:

..some stuff..

groovy myGroovy
copy xyz abc

... more stuff ..

Then in 1.7.4 you would have called groovy.exe, executed the program, then continued to copying the file. But in 1.8.x groovy.exe is deprecated so instead you execute groovy.bat. Unfortunately, when a Windows bat script calls another in that way, it effectively jumps to the script (with no return) so the script finishes at the end of groovy.bat. To fix this, use the Windows CALL instruction:

..some stuff..

call groovy myGroovy
copy xyz abc

... more stuff ..

With the CALL, the groovy.bat script executes and then returns control to your script, and the copy and more stuff actually happens.

NOTE: I think the reason I have the problem is that I installed the generic groovy rather than using the specific windows installer (eg here). But codehaus seems to be down right now.

Using Groovy AntBuilder to zip / unzip files

I've been quiet for quite a while - partly because I am not working with Oracle just at the moment. I have been building some automated workflow systems using Groovy as the scripting language. I've known about Groovy since James Strachan first invented it back in around 2002/3 - but this is the first time I've really been using it in earnest. It's a great for portable scripts, and for integration with Java (it runs in the JVM). It's much friendlier than Java for someone like me who comes from a PL/SQL and C (not C++) background.

Anyhow, I found out about using Groovy Antbuilder tasks, and have been using them to manage zipping / unzipping file sets:

def ant = new AntBuilder();   // create an antbuilder
ant.unzip(  src: planZipFile, dest:workingDirName,  overwrite:"true")

Then I found I wanted to flatten the output (ie don't reproduce the directory structure). The Apache Ant documentation for the unzip task shows the Ant XML:

<unzip src="apache-ant-bin.zip" dest="${tools.home}">
    <patternset>
        <include name="apache-ant/lib/ant.jar"/>
    </patternset>
    <mapper type="flatten"/>
</unzip>

How to add the mapper element?

Well, lots of googling later, I couldn't find an example but I did see the patternset being used. So thanks to that, I found that the Groovy way of expressing the mapper part of this is to add a closure after the call:

def ant = new AntBuilder();
ant.unzip(  src: planZipFile, dest:workingDirName,  overwrite:"true"){ mapper(type:"flatten")};

So I hope someone finds that useful.