Groovy Eclipse Release

The time has come finally for a release of the Groovy Eclipse plugin. The plugin has been published to the update site.

There are a few notes to make.

First off there is now refactoring support inside the plugin for your Groovy Code. To see this demonstrated head over to this wiki page. Besides documentation there are some pretty cool flash demos of the features which should entice.

Second, the groovy plugin now supports the 1.5.7 version of Groovy.

Third, this release does not contain support for the joint compilation of Java and Groovy code by the Groovy compiler. This is a priority for the next release, and is a perfect segue to the next note.

Fourth, please feel free to visit the wiki page Groovy Eclipse Roadmap. There the Groovy Eclipse team is collecting priorities and feedback for features to be added to future versions of Groovy Eclipse. The plan is to release another version here before the end of the year or soon after the new year, depending on the issues that are resolved, feedback from the community of users and the release schedule of new versions of Groovy.

Fifth, if you are having issues with the plugin, please contact either the Groovy Eclipse mailing list (you can subscribe here), follow Groovy Eclipse on Twitter. or browse/add JIRA issues here. Your feedback is much appreciated.

Finally, as the Groovy Eclipse project lead, I would like to thank our contributors that made this release possible, in particular Thorsten Kamann, Michael Klenk, and Heiko Bottger. Finally a shout out to Guillaume Laforge, for helping to keep Groovy Eclipse afloat and me on track. Thanks everyone!

Roadmap for Groovy Eclipse work

Hello everyone. I know Ed Povazan has not been active, so I will try and step in to fill the void. There has been activity on the Groovy Eclipse development mailing list requesting a roadmap for the future of plugin work. I know that I have been on a soapbox for a while now about how we need full time and paid work to support the plugin, but I think I should take a stab at what I think that the near future of the plugin should be. I think that the current trunk (or what is out on the dev update site) is a viable candidate for a release. I know I have been telling people over the last couple of months to use the updateDev site and not the main release update site. This is not an acceptable circumstance, the dev site is for internal or beta testing only, but the current release version of the plugin leaves me with no option. I know that there may be some refactoring coolness out there and I do not want to discourage progress in any way, but the current version of the plugin on the release site is quite frankly an embarrassment.

So given this state, I propose that we cut a release that includes Groovy 1.5.6 oand represents what is out there on the update development site, so that we can in good conscience tell people to point at the release update site. After the release of Groovy 1.5.7 so that we can accommodate the refactoring, we can include the new stuff and then release it to the development update site for evaluation. This is based on what I understood from the earlier emails that the refactoring work requires Groovy 1.5.7. After a time, a couple of weeks say, if it proves itself stable and ready, then lets push out a version to the main release site. This is relatively standard practice and I see no reason to circumvent it.

This does bring up an interesting point, a couple of years ago it was possible to get new versions of the plugin out quickly because there was a reliable set of beta testers that could give us feedback quickly. Scott Hickey's (the previous Groovy Eclipse lead) team working on a project would download the plugin and put it through its trials and we could find out trouble quickly. It would be interesting to discover if there is anyone out there who could fill this function. As an Eclipse developer, it is amazing how new eyes can find configuration, provisioning, installation and general plugin bugs when you thought everything was fine. This sort of feedback and work is vital.

If we can get regular activity restarted on the plugin (ahem... listening G2One?), I think that releases should occur at regular intervals of between 4 to 6 weeks, in line with common Agile iteration or spring intervals.

If no one has an issue with this, I will go ahead and build a new release and promote it to the main release update site.

As far as a roadmap goes, I had a brief chat with Scott Hickey (the old Groovy Eclipse plugin lead) and I think we came to a simple understanding.

* First, there is some major work that needs to be done under the hood to not have the plugin use the version of the groovy runtime installed in the workbench, but rather use the one that is set for the workspace.

* Second, there needs to be a structure like IJavaElement, or the equivalent, to allow the Groovy Eclipse plugin to support different versions of the Groovy libraries for different projects. The second issue is related to the first issue to some degree.

* Third, there needs to be better integration of the groovy compiler with Eclipse JDT support. I saw an example in the Scala Eclipse plugin where the project has the Eclipse Java nature added to the project, but the Java Builder was not added. This allows the Scala plugin to provide the scala tools to build the class files. I think that something like this should be done for Groovy Eclipse, especially since the groovy compiler will now compile java as well. This will also prevent collisions between the Java builder and the groovy builder.

* Fourth, we need to be chasing the standard that the good folks at IntelliJ have been blazing. The Groovy Eclipse plugin should try and provide most, if not all, the kind of support that IntelliJ is giving to Groovy now. I think what it does for dynamic methods is awesome.

* Fifth, refactoring tools need to be provided that are robust and first class. Hey great job y'all on this one, this kind of work aint easy. I am still intrigued by this notion, because I would love to see good dynamic language refactoring that is more than just grep and replace.

* Sixth, provide at least a basic level of support for Grails development. I know that there has been some work on providing Grails support, but I know it could only be of the very basic sort and there is so much in Grails that screams for IDE support. I mean how cool could it be to get help with writing those GORM domain classes for instance?

* Seventh, enable Eclipse Plugin Development using the Groovy language. This is really more of a personal desire, I think that Grails support or any of the other points I have listed would affect far more people. Still it would be nice to be able to do more and more Groovy Eclipse work in Groovy, right? I think so. As part of this effort we could try to leverage and improve Groovy support for EMF. Heck maybe we could make EMF usable! (*duck*)

* Eighth, as I stated above, if regular work can be restarted on the plugin, there should be regular releases on the order of 4 to 6 weeks apart.

* Ninth, after getting the plugin in a better state, we need to get companies like Genuitech, eBay and other eclipse distribution providers to start including the plugin, if not included by default, at least as an option. I will make a point to get it in to Genuitech's Pulse service.

Most of the points I came up with really were off the cuff, so if you can think of others, please don't keep it to yourself!

Don't call it a static or dynamic language!

I was talking the other day with someone recruiting me for a position. Smart organizations will contact you with someone who can try and sift the wheat from the chaff. In other words, they'll ask you questions in particular computer science or even, *gasp*, Java questions. Well this one guy asked me a standard question, 'what are the advantages and disadvantages of statically typed versus dynamically typed languages?' Now the full debate on that question could not only fill a whole series of blog entries, but could be a book by itself, which I will not get into here. Still as I was giving my answer I prefaced my comments by saying something that I have put a fair bit of thought into, which was: 'I don't like the name static or dynamic typing, I prefer the notion of implicitly typed and explicitly typed languages.'

Definitions
First off let me start with the definitions of explicit and implicit, both of these are horked from Merriam Webster Online. Implicit is defined as "capable of being understood from something else though unexpressed : implied or involved in the nature or essence of something though not revealed, expressed, or developed." Explicit would be defined as "fully revealed or expressed without vagueness, implication, or ambiguity : leaving no question as to meaning or intent" or as "fully developed or formulated ." I think a good way to think about this is to consider the following question, "are details hidden from you or not?"

WTF (What The Friendly) does this have to do with Programming Languages?
I think if you consider it for a while, the language debate between statically and dynamically typed is clearer when it is considered in terms of whether it emphasizes implicitness or explicitness. First off, all languages and programming platforms are implicit to some degree, since there is no way to encapsulate all of the factors that go into programming a software system to a developer. If they did, the resulting interface to the developer would probably be enough to make an airline pilot's jaw drop. Still the point applies if you focus on types. Most of the debate about programming languages focuses on the issues of types, so it is a good area to concern ourselves with. By my reckoning, a strongly/statically typed language, like Java for instance, would be considered 'explicitly typed' in this nomenclature. A dynamically/weakly typed language, like Python or Ruby for instance, would be called an 'implicitly typed' language from now on. An optionally typed language like Groovy would be optionally explicit or optionally implicit, depending on the developers mood that day. ;)

Actually in my opinion, most of the interest in Groovy is due to its 'implicit' capabilities and therefore I would really put in that category. I know you can explicitly type things in Groovy, but that is really an enabling feature. Enabling feature, you say? Yeah, an enabling feature, kinda like (Note: I have no personal experience with the following analogy, really...) how a drug dealer might give out free samples to hook you in and then afterwords start charging. So being able to specify types in Groovy gives Java developers, like myself, a warm fuzzy about trying out the new features and, therefore, try out the Groovy language.

Ok this is awfully pedantic, so what?
So the question that might be formulating in your mind is, "ok so you have a new definition, how does this help anything?" Well for one thing, no matter what you do with software code, the types are there, period. The difference is if they are hidden or not. In the next few sections I am going to compare equivalent sections of code in Java and in Groovy, but I think that the point holds if we were in Ruby, Smalltalk or Python, even though the examples would vary.

I want to show a quick example from groovy and Java, in this I am going to create an instance of ArrayList:

Java(5.0+):
List<> list = new ArrayList<>();

Groovy:
def list = []

So let me ask you a question? What is the difference in this case? Well for one the amount of actual keystrokes to write the examples. Beyond that, there is not much difference, in both cases you have a variable declaration of list that is initialized with a java.util.ArrayList instance. So what is the advantage of the Java version? Well Java's explicitness is key here, you know straight away that list is of type java.util.List and that it is an instance of java.util.ArrayList. Therefore, someone new to the Java platform would probably have an easier time figuring out what is going on in the Java line(at least not including generics, which is another post entirely) than with the Groovy line. To understand the groovy line you need to know that the array notation is shorthand for instantiating a List object and that by default an ArrayList is used, therefore I would term Groovy an "implicit" language in this case.

One other not so small point, if I was looking at this from a tool developer's viewpoint, I prefer the Java version to the Groovy version, in probably just about every case. In general, it is easier to write tools to analyze and provide support to base Java (or other explicitly typed language) than it is to any implicitly (read: dynamic) typed language.

Another example, I am going to do the simple "HelloWorld" application in both Groovy and Java:

Java: HelloWorld.java
public class HelloWorld
{
public static void main( String[] args )
{
System.out.println( "Hello World!" );
}
}

Groovy: HelloWorld.groovy
println "Hello World!"

This is the example that should drive the point home. What is the difference? In the end the bytecode will be functionally the same in both the Groovy and Java cases (Notice I don't say that the bytecode would be exactly the same). The big difference is that the Java version is explicit, not only about types, but also in requiring a class definition and explicit main method. In Groovy, the type is inferred implicitly from the file name and the main method is also implied.

What about the tools man?
The final example I want to consider is the Domain Specific Language (DSL) in the two kinds of languages. Actually, I lied, I am only going to show an example of a builder in Groovy and skip showing the example in Java, because the example for Java would be far too painful to consider. I want to consider the following example because I want to get to the point about what 'explicit' versus 'implicit' means for tool developers.

Example: AntBuilder (Groovy)
// Going to zip up a file
def ant = new AntBuilder()
ant.zip( destfile:"${zip.location}", basedir:"${project.location}" )

What all is going on here? You have an instance of AntBuilder being created and a method called zip being invoked. There is an example of named parameters, which is a very cool feature for Groovy I think. Finally, you see there two GStrings (Groovy Strings, quite the name no?) with its built in templating. There is a lot going on here, someone wanting to write a tool would probably take a deep breath, but envision that he/she will be able to do it. The trick is what about the zip method. What about the zip method? Lets get to that next.

In the previous examples, the types and their signatures are just below the surface so to speak. The notation '[]' is a shorthand for java.util.List and in the case where the statements are just put into the Groovy file without a class definition, means there is an implicit class definition and static main method. In the above example, there is no such nicety. Why would I say that? I mean the variable ant is an instance of AntBuilder right? Yes, but look at the javadoc for AntBuilder, where is the method definition for zip? There is not one, but if you want to see for yourself go ahead and look, I'll wait.

The AntBuilder class is an example of a Builder in Groovy which does something like what java.lang.reflect.Proxy does. Proxy provides an InvocationHandler, which has a method called invoke() which the Java platform provides as a hook to allow you to provide runtime implementations of arbitrary types. The Groovy Builder support allows for creation of nodes and invocation of methods on those nodes. All of this means that not only is the full type definition for AntBuilder implicit, but that there is really no way at compile time to figure it out. What I mean is that there is no way for a source code tool developer to write general tools to provide the kind of language support that is available in explicitly typed languages for DSLs. In the first two examples, you could easily imagine being able to provide tooling support for those cases, the types and signatures were implicit, but they could be figured out relatively simply, there is no real way to do it in the last case.

Tooling support is an area that is usually skipped in alot of discussions on explicitly typed versus implicitly typed languages. It is dismissed by implicit proponents with, "well tooling will just catch up." I don't consider it trivial and, having dabbled a bit in providing IDE support for Groovy, I don't assume that the tooling will just be there in the future. Implicitly typed language designers and proponents need to give this its full consideration, elsewise the best your language could hope for is to be the next Lisp, praised by some and used by none.

Conclusion
So the difference between the two languages in the above examples is best exemplified by asking three questions. First, which version do you think someone new to your codebase or the Java platform would understand better? Usually an explicitly typed language like Java (or maybe Scala/Haskell) would be favored. Second, which version do you think someone with experience with your codebase or the Java platform would prefer to write? Usually, I would think that an implicit language like Groovy, Ruby or even Python would be preferred. Third, what kind of tool, particularly IDE support do you want or need? If your project thinks that the first question is more important than the second one, then an explicit language like Java should be your choice. If the second question seems more important, then an implicit language like Groovy should be your choice. The third question can only be answered by surveying what is available and trying it out to see if it is good enough.

JRuby on Rails good or bad for Java?

I am going to apologize for the incendiary title. I think the work the JRuby team has been doing at Sun, particularly with enhancing the JVM for dynamic languages, is great and a service to the entire Java community. The real point of this post is a question to Sun and the rest of the Java community. What is the question? Simple. Y'all why all the emphasis on JRuby and JRuby on Rails and not an equivalent amount of love (read: attention/resources) to the Groovy/Grails platform? I am combining consideration of both Ruby and Groovy with their equivalent Web frameworks RoR and Grails since they really are the killer apps (read: primary motivation for developers to try them) for both languages at this time.

So why all the attention at Sun to JRuby? Well I think there is probably a mentality at Sun to think they need to win more people over to the Java platform. That thinking leads them to wanting to support Ruby and Ruby on Rails on the Java platform. This is not the end of the world or necessarily bad thinking. Why? Well you would think the more developers on the Java platform the "mo' better" right? I admit that being a Groovy/Grails proponent, the attention leaves me a bit jealous, but as I said earlier, they have been doing good work and, you know, envy gets you nowhere. Still it begs the question, what about the people who are already on the Java platform doing their work? What is being done to improve their experience and to keep them happy working with the Java platform?

Note: I keep referring to the Java platform since Java really encompasses three components, the JVM runtime, the platform libraries and the Java language. I think of the platform as the libraries and the JVM, in other words, the full Java runtime minus the development time Java language support.

Give Groovy Some More Love Everyone!
Groovy/Grails is native to the Java ecosystem and should be (read: is) easier to support on the Java platform. Groovy/Grails has a far flatter (read: easier) learning curve for existing Java developers. How do I know that it is an easier learning curve? Simple, Groovy is the single reason I have not really tried to do development work in Ruby or another dynamic language. Every time I started to drift off the reservation, for one reason or another, I found that Groovy had it already. So why give up the JVM or platform libraries of which I am very familiar? Grails, the Groovy Web Framework, is still a relatively young technology, but is already showing signs of being one of the, if not the, best Java web frameworks out there. It is amazing how Grails is picking up speed right now. <sarcasm>Its like people want a better way to do Java Web applications and, get this, don't seem to be willing to dump all their previous experience with Java or their previous Java work in the trash. Isn't that just crazy??</sarcasm>

So therefore, I think Groovy/Grails is something that should be better supported, particularly with tooling. A better Groovy/Grails would help keep developers on the Java platform, how? Well remember there does not exist a Groovy/Grails platform outside the JVM and Java platform libraries.

Besides the fact that Groovy/Grails support should be far easier to achieve than Ruby/RoR support, there is the converse argument about JRuby and JRuby on Rails (JRoR?) bringing people to the Java platform. JRuby on Rails could also be viewed as a conduit for allowing development to leave the Java platform as well. Why? Well all new work could feasibly be run on native Ruby platforms if run on JRuby and, in fact, would probably run better on native Ruby platforms than inside the JVM. So unless you have lots of legacy with J2EE, there would be no hook to staying with the JVM or Java platform. Now I hate vendor lock-in, but Java has no vendor to speak of. I am all for allowing existing Ruby/RoR developers to try the Java world, but the question is where should your emphasis lie? I don't think that the Ruby world is anywhere near the size of the Java world, even on the Web.

So, in conclusion, the question is, is it more important to convert others to the Java platform or is it more important to keep and take care of the large Java developer base on the Java platform? My answer is yes. What do I mean? Well you can't just grow a community, you must also take care of what is already there, both aspects are important to a thriving community.

So please Sun, get past the NIH (Not Invented Here) syndrome and go hire a Groovy guy next to Mr. Nutter (no complaints for Mr. Nutter, he has been doing good stuff on the JVM for all dynamic languages). While you are at it, I am going to suggest (even though I am an Eclipse guy) putting better support in Netbeans for Groovy. I am getting a little tired of hearing how IntelliJ is by far the best environment for writing Groovy. I would also suggest improving the Eclipse plugin, but I don't think y'all will go for that(would you?). Any help to Groovy would be in your interests, you wont regret it.

For the rest of the Java community (especially the Groovy/Grails subset), I think I am going to start sounding like Public Broadcasting in the United States during sweeps. If you don't know what I talking about, they are officially called "Pledge Drives", unofficially they are called "Beg For Money Drives." So here goes in my PBS pledge drive voice**:

"Please pledge your support to Groovy Eclipse today. At the 1+ full-time developer level we'll get you an Eclipse mug and sticker. Show your Eclipse pride everywhere you drive or compute, your choice. At the 2+ full-time position level, in addition to the mug and sticker, we'll get a Groovy Eclipse shirt made up for you from somewhere. You know you have been enjoying Groovy/Grails for some time now and been looking for your opportunity to contribute, here is your opportunity. You wont regret it, I promise*."

Seriously, the Java developer world today is on Eclipse (not IntelliJ or Netbeans or whatever), so for Groovy/Grails to grow and be taken seriously by the vast majority of Java developers, Groovy Eclipse has to be first class. Like I overheard once while talking about this subject to a group of people, "People will change languages faster than they will change their IDE(s), so for me to introduce Groovy to my Java developers, I need it on Eclipse."

* If you do regret it anyway, just remember two things. First, I thank you for your support. Two, you may rant and rave at me, but limit it to emails, no 2am crank calls, please. :)

** I think I watched way way too much PBS as a child or something, but where else could I watch Dr. Who before the Sci-Fi network existed??

Beware GStrings and their IDE support!

Despite the lascivious implications of the title, this blog entry has a G rating, as in Groovy!! You know, before I continue, I would like to apologize to y'all out there. I realize that punnery is considered, in the eyes of many, to be the lowest form of humor. But you know, why oh why was the name GString chosen and permitted to persist? Even though I am a strong Groovy proponent (some accuse me of being a fanboy), I can't stop the little 12 year old pubescent child in me from snickering every time I read about Groovy 'GString(s)'.

I want to preface my comments by saying that I love Groovy Strings (aka. GString(s)). I love the multiline strings, I love the ability to create regular expressions without slashing yourself all up, I really love the templating or string interpolation that allows arbitrary groovy expressions to be embedded in a string expression and I even love the fact that the GString is lazily evaluated. So why the title? I will get to that next. Before I continue, for you nit-pickers out there, I know that a GString is strictly only a string expression that is double quoted and contains an unescaped dollar sign, so I suppose I should have titled the blog entry as 'Beware Groovy String Support from within IDE(s)!', but really what fun is that?

As I started using Groovy and learned about its support for strings, I grew to love single quoted strings. Single quoted strings are the closest thing to Java string literals, they are immutable and are never evaluated to GString(s). They appeal to my need for simplicity. The problem comes later, as I write code, especially Unit Testing code, when all of a sudden I want to use a GString.

What is the problem? Why don't I just switch the single quotes to a double quote and voila! You ever try it? I don't know if IntelliJ's allegedly miraculous Groovy support does the same thing, but my baby, the Groovy Eclipse plugin sure does annoy me on this one. I suppose I could do a find and replace, but often my first instinct is to use the cursor keys and use that backspace button baby! And when I do that I run smack dab into a little feature that wants to autocomplete the double quotes, you know take " and change it to "". That is fine, but my first instinct is to hit backspace to remove the second and unnecessary double quote, which causes both of the double quotes to vanish, not what I want! So usually I stop, mutter an obscenity under my breath to myself, move my cursor in-between the two double quotes and hit the delete button, which I almost never use except in this one case.

Maybe this is more of a commentary on my coding style and how I interact with the IDE, but it has forced me to reconsider how I use strings in Groovy. From now on, I will try and avoid single quotes like the plague and use them only in cases where they are explicitly called for. In other words, I will no longer use the '' (single quoted) strings in groovy by default and instead use "" (double quoted) strings.

You know there is one other reason for this switch. I have had on occasion the need to convert my Groovy code to Java code and, other than the missing semicolons, fixing single quoted strings to be double quoted is second most laborious/annoying/mind-numbing step I have had to take.

So it is double quoted strings from now on for this boy.

Using Groovy for Unit Tests inside Eclipse

I have blogged before in the past about using Groovy to write Eclipse Plugins. In fact, I think I am the only person in the world to ever write about the subject ever. This lack of interest in the subject is unfortunate for many reasons, but one reason in particular is the fact that writing in Groovy as opposed to Java can make many plugin related tasks simpler, particularly a lot of the tasks that make writing plugins no fun. For this specific reason, I am considering giving giving Groovy EMF a hard look as part of my ongoing efforts to make sense out of the Eclipse EMF Project. In my opinion, EMF could be like Grails if the generated code were in Groovy instead of Java.

Still I wanted to focus the blog entry on the use of Groovy for Unit Tests inside of Eclipse. This is because, in my opinion, that writing Unit Tests in Groovy is one of the main entry points for a Java developer to get their feet wet with Groovy and to see its benefits (the other two cases, in my opinion once again, are XML document parsing/generation and scripting). So here goes.

Framing the problem
The trouble with using Groovy in your projects is the same for using it for Unit Tests as when using it in production code from within Eclipse. The problem is that you usually have a build process that is run from the command line, often referred to as headless mode that you use for continuous integration or releases, and then you have the incremental build process that runs from within Eclipse. For headless (or batch/command line) builds, there is support from Groovy to assist with this, first there is the groovyc command that is equivalent to javac and second there is the Groovyc Ant Task. To take advantage of Eclipse incremental builds you really need to have an Eclipse plugin supporting that for you. This is where Groovy Eclipse can really be helpful, it provides the needed plugin support for incremental builds for Groovy from within Eclipse. For the next sections we will focus on solutions for utilizing Groovy for Unit tests.

Solution 1: GroovyTestSuite
There is a short snippet on using GroovyTestSuite from within Eclipse. There is one strong advantage to this method, since the groovy code is compiled when the AllTests are run, ostensibly this method could be used in both the headless batch build and from within Eclipse without any changes. So why not just use this method? Well there are downsides:

1. You can't use Eclipse's nice 'Recreate Test Suite' operation to keep the AllTests suite in sync. Over time, this is one of those problems that will bite more than once and usually when you least expect it.
2. If you don't have unit test classes compiled to classfiles, it makes running individual test cases difficult. This is something you feel more when you are trying to get a particularly challenging testcase to pass, in addition to the added compilation time, you will have to run the suite again. Of course you could create a new JUnit Testsuite just for the testcase you are trying to run, but then don't forget to delete it when done and don't check it into your source repository.
3. You have to make an assumption as to the current working directory. If you notice in the example code for GroovyTestSuite you have to assume that the unit test runner is being run from the project source directory. This is fine for Eclipse, just remember to check if that assumption holds for your batch/headless build as well.
4. You have to make assumptions as to the testcase's package. Once again refer to the code example for GroovyTestSuite. In the example see that the source directory, the package path is hardcoded, and the groovy file name is hardcoded. This is fine as long as you never change the source directory or refactor your test code into other groovy files or java packages, (*sarcasm alert*) which will never happen right? Now admittedly if you run your unit tests early and often, you will see this and then you will go and fix them immediately. Still better to not have to make those assumptions right?
5. Be careful about making Groovy code dependent on Java code or vice versa from within the same Eclipse Java project. This is a problem shared with the second approach as well. It is something you must consider (I know that groovyc will now compile Java code as well and it should be evaluated for use from within Groovy Eclipse or from your external build processes). There are a couple of ways to deal with the issue as I currently understand it. First, if you write only Groovy or Java code in a test project, there is no problem. This is usually an ok solution for greenfield test writing, but will not hold long term. Secondly, since there are no generated classfiles from groovy code in your project, you cannot allow your Java code to rely on any groovy code in the same test project period.

Solution 2: Groovy Eclipse Plugin
There is another option from within Eclipse, install the Groovy Eclipse Plugin and then add the Groovy builder and nature to your JUnit test project. Why do this? Well Groovy Eclipse will compile your Groovy code to classfiles and place them in a class folder for Eclipse so that Eclipse sees the compiled code as just another set of compiled Java code. This means that GroovyTestSuite is unnecessary and that running tests will not incur the full costs of compilation at start time, a significant advantage for developers. Another advantage is that the unit tests are compiled, so it is possible to easily run one testcase at a time. If setup correctly, using the Groovy Eclipse plugin makes developing/using Unit Tests in Groovy as seamless and invisible as possible. "So", you may ask, "ok Groovy Eclipse fan boy, what are the tradeoffs?" First off, even though I am a Groovy Eclipse committer and supporter, I am very well aware of its shortcomings, so I am not a fan boy. Secondly, well here are the tradeoffs/issues with this approach.

1. You must include Groovy as part of your batch/headless build process to compile the Groovy Unit Tests first, before the Unit tests are run. This is the same trouble you have if you are using Groovy in your production code. I will refer you to the section above titled 'Framing the Problem', for approaches on dealing with this. Using GroovyTestSuite only requires access to the groovy libraries at runtime.
2. Be careful about making Groovy code dependent on Java code or vice versa from within the same Eclipse Java project. This is not a problem unique to Groovy Eclipse or to writing Unit Tests with Groovy, but it is something you must consider (I know that groovyc will now compile Java code as well and it should be evaluated for use from within Groovy Eclipse). There are a couple of ways to deal with the issue as I currently understand it. First, if you write only Groovy or Java code in a test project, there is no problem. This is usually an ok solution for greenfield test writing, but will not hold long term. Secondly, be careful and avoid the following circumstances, A.groovy depends on B.java which depends on C.groovy or A.java depends on B.groovy which depends on C.java. This is an issue that needs to be addressed in Groovy Eclipse generally, either by leveraging groovyc to compile Java code or do an analysis to provide an Error/Warning marker to the user about the above circumstances. A useful heuristic traditionally is to allow groovy code to depend on java code or java code to depend on groovy code but not vice versa in the same project. If you hold to that heuristic, just consider the issue raised by number 3.
3. The order of the builders in the .project file. First off if you have groovy code depending on java code or vice versa in the same project, make sure that the groovy builder is before or after the java builder in the .project file. This can be easily checked by right clicking the project and then bringing up the properties dialog. Just look for the Builders section, you can easily remove, add, or reorder the builders in your .project file. Secondly, there are other occasions to be careful about the build order. In particular, this one bit me yesterday when I was trying to write a couple of unit tests for Eclipse monkey in groovy. I was pulling my hair out and about to give up on groovy unit tests for monkey (I mentioned I am not a Groovy Eclipse fanboy didn't I?), when I remembered to check the builder order. Sure enough, the groovy builder came after the plugin and manifest builders. Reordering the groovy builder to come before the PDE builders then allowed the PDE JUnit to actually run (Note to self: add better PDE support for Groovy Eclipse).

Conclusion
There are advantages and disadvantages to both approaches to writing Unit Tests for your projects from within Eclipse. The first approach, at first, seems more straightforward and simple, in particular no integration with external builds, compilation of groovy code is reduced to a classpath resolution problem. The second approach, using Groovy Eclipse, leaves the developer with the need to integrate Groovy into their external build processes, but in the longer term provides a more seamless and productive experience. So if you are wanting to write Unit Tests in groovy, give Groovy Eclipse a try!

Groovy Presentation at eBay available

I got the opportunity to present an introduction to groovy at eBay this past May 9th. It is now available from the Groovy Codehaus site at: http://groovy.codehaus.org/presentations/Groovy_eBay_2008May09/GroovyJamesErvin.html

Thanks to Dave Marsland and others at eBay for giving the the chance.

Note to Microsoft, getting WebDAV to work on Vista should not be *that* difficult.

Remarks from the Groovy Meetup before JavaOne

I went to the Groovy meetup yesterday in San Fransisco and I can tell you that the primary effect on me was to get me all geeked up again for Groovy. Now I don't want to leave the wrong impression, I wasn't upset with Groovy at all or anything. What I will say is that I thought that the excitement in the room was palpable and I definitely feel that Groovy is finally coming out of its 2004 pre-JSR malaise and really about to achieve its potential. Now I know being in a hotel conference room with a bunch of people who are obviously Groovy partisans does not a trend or good prediction make but I defend the statement on two grounds. One, my gut feel is not solely based on what I sensed yesterday, but rather based on what I have seen on the net and experienced as a Java developer working with Groovy. If you are a Java developer and well aware of its pain points, how can groovy not appeal to you, I mean really? Second, its my opinion, which I am entitled to have and be wrong about (which I don't believe I am wrong in this case).

One of the points that Guillaume, the Groovy project manager, brought up in his presentation, was the improvement of the performance of the 1.5+ Groovy runtime. I can say, without equivocation, that the improvement in performance is indeed extraordinary. In fact, he left out of his presentation the area that I think that Groovy 1.5+ has improved most on, was compiler performance. I would put compiler performance improvement to be on the order of magnitude better. Now I do not have any micro-benchmarks or pseudo statistics to back me up, but I will say that this is my gut feel based on my experience with Groovy Monkey. On the machine I currently use for my work (Windows Server 2003/Quad Core/8 GB RAM/IBM JVM 5.0/Eclipse 3.4M5), I would say that before Groovy 1.5, the scripts I would write that would invoke other monkey scripts, could be very very slow, on the order of a couple of minutes or more. Now those same scripts are running like well under 30 seconds and this result is not based on any changes to Groovy Monkey or any of the underlying platform. All I can say is wow!

Groovy Eclipse
I do have a comment on a slightly bitter note. I am a committer to the Groovy Eclipse project and it pained me to hear how it was mentioned that the plugin was more of a impediment than an asset to Groovy's adoption. I will admit that I myself began to get frustrated with it (and there are still some frustrations) a couple of months back. Still with the newer Groovy runtime and the latest submissions to at least the development version of the plugin, it is a far far better product.

Still there is the point that even with the latest improvements that the Groovy Eclipse plugin is still lagging significantly IDE support from IntelliJ. First off I want to mention, congrats to IntelliJ. Even though I am primarily an Eclipse developer, I am probably going to try it out just to see the Groovy support and this is a point to which I want to get back to. Still both IntelliJ and NetBeans have people working full time on the Groovy IDE support, which is great for people using those platforms, not so great for the vast numbers of developers using Eclipse. The point I want to drive home is that, as I have learned from personal experience, IDE integration is both vital to the success of a language or framework and hard to do. Now I may fiddle around with IntelliJ (or even, *gasp* NetBeans) to try out their Groovy support, but do you really think that the vast legion of Java developers using Eclipse are really going to take a hard look at Groovy without first class IDE support? I don't believe so and I would think that just about everyone would agree with me on this point.

So how do you address this? Simple, there needs to be a small group of well motivated and competent Groovy and Eclipse plugin developers that can be dedicated full time to Groovy Eclipse. In my experience, only people working full time focused on IDE support could give Groovy Eclipse that first class spit and polish which can impress developers trying Groovy for this first time. I mean, Project Zero and Scott Hickey's work with Mutual of Omaha has contributed much to the plugin and there are some nice contributions being made currently by people in their free time, but this is not their primary focus. Even though the plugin continues to evolve under current circumstances, this would not compare with the strides that could be made by people working full time. Are you listening Guillaume, Mr. Guan, others, anybody?? I mean there has some buzz about Groovy being the next version of Java and I know that Guillaume and others have stated that there is no intention of Groovy replacing Java, but can you imaging Groovy reaching its potential without great Eclipse IDE support? I know that I just repeated that point from earlier, but it bears repeating.

Back to the meetup
Now back to the Groovy meetup. I would also like to point out that I was much impressed with the presentation from the folks at Linked In. I am already a user of their product and I am even more impressed to the degree to which they appear to be driven from the Engineering perspective. Besides, they are really starting to use Groovy and Grails in anger! How cool is that man? I love the fact that they and, I believe it was, Sky television are showing that Grails is like RoR, but with stability and scalability added at no extra charge. That is so cool and can demonstrate how getting better IDE support for both Groovy and Grails could make such a difference.

I am looking forward to the future of Groovy and crossing my fingers that there wont be too much backward compatibility breaking between now and Groovy 2.0.

Add Groovy to your Eclipse Plugin Projects

I have begun some basic work on the Grails Eclipse plugin that I outlined in a proposal in a previous post. One of the features I want to highlight will be the fact that I want the plugin to be almost exclusively written in Groovy instead of Java.

As I start work on the plugin, I want to highlight a feature that I will hopefully add to the Groovy Eclipse Plugin in the real near future, Groovy PDE Build support. If you install the Groovy Eclipse Plugin ( I think the version currently in Head/Trunk is better than the one on the update site ), you will find that your development for the most part goes smoothly, except for when you start using Groovy to write your Eclipse Plugins. The issue is that the PDE Builder doesn't know, and probably doesn't want to know, about the Groovy code and its need to be compiled with the Groovy compiler. So how do you deal with this?

One way is to parallel the work of the Eclipse PDE Build team and write your own scripts that can interpret the build.properties file to export your plugin yourself. This can make you proud and think you are a real programmer, except that why in the heck do you want to repeat something that has already been done?

Another way is to generate the build.xml file, click the custom build option on the plugin and maintain the ant build file manually. Do I need to go into the obvious problems and pain with this option? If you like pain, reading ant XML scripts, pain, deciphering the incredibly ( but probably necessary ) complex PDE build process, pain, keeping your Ant XML file synchronized to changes in your project manually, and yet more pain, go ahead. I wont stop you, for the rest of us I am going to cover the next, and I believe, better option.

One side note, I am very familiar with the pain that I described above, I wrote a series of Groovy scripts to build our products, as per the first option. Pretty cool and better than the second option, but it really was a source of pain and, as I will now show you, unnecessary work.

The final option I give you, with an example, is what I think to be the best option. In fact, I wish I knew of it before on previous Eclipse based projects. As of Eclipse 3.2, you have the ability to specify a custom callbacks XML file.

To add Groovy PDE Build support to your plugin project, first you must install the Groovy Eclipse plugin and enable the groovy nature for your project. Deployment of the groovy libraries into your plugin for installation is another topic for another time.

Afterwards goto your Eclipse installation directory and open up the plugins directory. Goto the org.eclipse.pde.build plugin installation directory and look in the templates/plugins subdirectory. You will see there a template called customBuildCallbacks.xml, import this into your project.

Now open up your build.properties file and add a property called customBuildCallbacks like the following example:

customBuildCallbacks = customBuildCallbacks.xml

This means that the build will now reference a callback Ant Build script in my project called customBuildCallbacks.xml in the root of my project. You could prepend a project relative path to the file name to place the file somewhere else if you choose.

The next step I like to do is to right click the manifest.mf(plugin.xml) file and ask the PDE to generate a build.xml file. Now I am not going to keep the build.xml file around very long nor its javaCompiler args file. I am going to use it to extract the targets that will be called in the callback ant script and to find out the name of the classpath reference that will be used.

Below is an example file from the plugin I am currently working on.

<subant antfile="${customBuildCallbacks}" target="pre.@dot" failonerror="false" buildpath=".">
 <property name="source.folder1" value="src/"/>
 <property name="target.folder" value="${temp.folder}/@dot.bin"/>
 <reference refid="@dot.classpath"/>
</subant>
<!-- compile the source code -->
<javac destdir="${temp.folder}/@dot.bin" failonerror="${javacFailOnError}" verbose="${javacVerbose}" debug="${javacDebugInfo}" includeAntRuntime="no" bootclasspath="${bundleBootClasspath}" source="${bundleJavacSource}" target="${bundleJavacTarget}"  >
 <compilerarg line="${compilerArg}" compiler="${build.compiler}"/>
 <classpath refid="@dot.classpath" />
 <src path="src/"   />
 <compilerarg value="@${basedir}/javaCompiler...args" compiler="org.eclipse.jdt.core.JDTCompilerAdapter"/>
 <compilerarg line="-log '${temp.folder}/@dot.bin${logExtension}'" compiler="org.eclipse.jdt.core.JDTCompilerAdapter"/>
</javac>
<!-- Copy necessary resources -->
<copy todir="${temp.folder}/@dot.bin" failonerror="true" overwrite="false">
 <fileset dir="src/" excludes="**/*.java, **/package.htm*"   />
</copy>
<subant antfile="${customBuildCallbacks}" target="post.compile.@dot" failonerror="false" buildpath=".">
 <property name="source.folder1" value="src/"/>
 <property name="target.folder" value="${temp.folder}/@dot.bin"/>
 <reference refid="@dot.classpath"/>
</subant>

There are two subant tasks that are of interest one before the javac task and one after. You can overload one or both in your callbacks ant script to allow the groovy builder to run before, after or before and after the java compiler. The important thing here is that the target name and classpath reference in your callbacks script must match.

Here below is an example from my current plugin project.

<target name="pre.@dot">
</target>

<!-- ===================================================================== -->
<!-- Steps to do during the compilation target <name>, after the compile   -->
<!-- but before jaring.  Substitute "name" with the name of the compilation-->
<!-- target, eg @dot                                                       -->
<!-- Available parameters :                                                -->
<!--   source.foldern : n = 1 ... N, the source folders                    -->
<!--   target.folder  : where the results of the compilation go            -->
<!--   <name>.classpath : name = name of the compilation target. A         -->
<!--                      reference to the classpath structure.            -->
<!-- ===================================================================== -->
<target name="post.compile.@dot">
 <path id="org.codehaus.groovy.eclipse.libs">
  <fileset dir="../org.codehaus.grails.eclipse/grails-home/lib">
   <include name="**/*.jar"/>
  </fileset>
 </path>
 <taskdef name="groovy"
          classname="org.codehaus.groovy.ant.Groovy"
          classpathref="org.codehaus.groovy.eclipse.libs"/>
 <taskdef name="groovyc"
             classname="org.codehaus.groovy.ant.Groovyc"
    classpathref="org.codehaus.groovy.eclipse.libs"/>
 <delete>
  <fileset dir="${target.folder}" includes="**/*.groovy"/>
 </delete>
 <groovy classpathref="@dot.classpath">
  def classpathString = task.classpath.list().toList().findAll{ new File( "$it" ).exists() }.join( File.pathSeparator )
  ant.groovyc( srcdir: properties.'source.folder1', 
      destdir: properties.'target.folder', 
      stacktrace:'true',
      classpath: classpathString )
 </groovy>
</target>

The important things to notice are that the targets are called pre.@dot and post.compile.@dot which were derived from the generated ant build script and could be derived from your build.properties file. The next thing to notice is the classpath called 'org.codehaus.groovy.eclipse.libs' that points to a directory and slurps in all available jar files. This is done to locate the groovy library and therefore the groovy and groovyc ant tasks. You must set the path, either relative to the workspace or hardcoded from your file system. The last thing to notice is the use of the sourceN.folder properties, if you have more than one source folder that is being compiled into your plugin, then you must make allowance for it. If you are not sure, go back to the generated build.xml, it will tell you since it will set those properties before making the subant call to your customBuildCallbacks.xml script.

Conclusion

What is the point of all this? Well simply put, once you have made these modifications, you can write groovy code in your plugin and have the Eclipse PDE Builder/Exporter compile your groovy code along with your bundle with no muss or fuss. This functionality works if you are exporting a plugin, or as part of a feature or as part of an update site. Cool eh?

One last point, since most of this is rather rote cut and paste, I am looking to enhance the Groovy Eclipse Plugin to handle this for you. Hopefully it should be part of the next official release on the update site.

Grails Eclipse IDE Support

I knew that the idea of an IDE plugin to support Grails could not be new. So I am going to post the contents a nice little "IDE Integration Wish List" from the grails wiki site. I am then going to make a proposal for what I see the path of a Grails Eclipse plugin would take. Comments are more than welcome.

IDE Wish List (from grails.org)
Below are the features that would be great to have from a Grails IDE:

• Wizards to create Grails artifacts like controllers/domain objects and so on. Unlike Rails, Grails doesn't do any background configuration with its command line tools so these can merely be simple wizards
• Running a Grails server embedded in the IDE and being able to step debug the application. Groovy provides all the information in the classes necessary to enable step debugging of Groovy code
• Code navigation with keyboard shotcuts and CTRL+click between Grails artifacts like controllers domain classes etc.
• Code completion for things like dynamic finders and persistent methods like save/delete/findAll/findBy* on domain classes
• Auto-completion of Grails tags in GSPs
• Integration of an embedded Grails console to be able to execute arbitrary scripts against a running application
• Being able to right-click execute Grails unit tests and get green/red bars etc.
• Being able to right-click on a Grails project and execute all unit tests
• Being able to right-click on a domain class and click generate to generate a controller and views for CRUD
• Better editor support for groovy files. This means autocompletion and so on.
• Special outline views for Domain-Classes, Controllers and Views
  Graphical editor for Domain Classes, with a UML-like or ER-like view
• The IDE should hook into Grails' upcoming plug-in architecture to be able to do things like auto-find new executable scripts, download and install new plug-ins etc.
• Integration of every Servlet-Container to test the Grails-App. The best solution were intergration into webtools
• XP Refactor support (e.g. rename methods/groovy file names and cascade changes to all dependencies)

Proposal
I would like to start by taking the Grails application and embedding it within a set of Eclipse plugins and then have Eclipse plugins to be able to run directly from the workbench ( via right click options ) the command line commands directly. This would mean that you would not have to install Grails seperately, kinda like Eclipse handles ant.

After that I would like to begin integrating the Groovy Eclipse plugin into the mix. I think that the Groovy Eclipse plugin should be included seperately from the Grails plugin to avoid issues of differing Groovy versions ( that Grails could require different versions from the main Groovy distribution ) and to avoid the overhead of installing all the Grails libraries along with the Groovy Eclipse plugin. Of course, there would be lots and lots of overlap and we should be able to leverage any new improvements in the Groovy plugin quickly. The Groovy Eclipse plugin with its editor and outline view would be the basis for adding more support for Grails.

After the Groovy Eclipse plugin functionality is added, the fun can really begin. As I mentioned in a previous post, convention over configuration would allow us to inject suggestions to method completion. A first target would be the Data Source configuration files, a second would be the Domain classes, and so forth.

A related issue would be to find an open source JSP Editor project that would be willing to partner with us to help develop the GSP Editor. If an acceptable one is not found, then one will have to be fabricated, probably based on a previously existing XML editor.

I think this could be very useful ( i.e. cool ) and since we could leverage already existing tools, we could have something to show rather quickly and have a nice evolutionary path to add new features and functions a little bit at a time.

I would love comments on this proposal.

Convention over Configuration == Eclipse IDE completion support for Grails?

As I am going through the "Definitive Guide to Grails", I can definitely say that for the most part things are going well. I wish that the dynamic update feature would work, but other than that things are going well.

One thing that has been hitting me like a pile of bricks, is Grails' use of injection to put properties and methods onto an object without it needing to extend a base class. This is all fine and dandy, but who can remember all those extensions easily for like a domain class? I know the IDE can.

As work has been progressing on method completion on the Groovy Eclipse plugin ( great work Ed ), it occured to me that adding additional completion options based on the fact that the project is a grails project should not be very hard, not hard at all. In fact, I did something similar in Groovy Monkey to add autocompletion and elements in the outline view based on what the script's binding was. How cool would that be, to not have to remember the domain's class' get, what actions are injected automatically into a controller, to perhaps provide some assistance to using the findBy* methods?

In fact, the way I think about it, using conventions is a bit like having static type information around. And if you have some equivalent of static type information, don't autocompletion and other IDE goodies follow?

Why dig into Grails?

During my time as a C/C++ then Java developer, somehow I have avoided the need to write J2EE web applications. Not web enabled or web services applications, no I have somehow avoided the beast that is J2EE ( not to mention *gasp* EJB ). However the current Web 2.0 ( I read AJAX ) wave has forced me from my comfort zone ( replace 'comfort zone' with Happy Gillmore's 'Happy Place' if you like ).

*Note: when I read AJAX I read, browser based client side UI programming and not alot of buzzword happy nonsense.

I have to admit that the current wave of browser based web applications are pretty cool. I love GMail, blogger.com's interface, Google Reader, Google Calendar etc... I don't think of myself as a google fan boy, but that is another topic ( hmm... maybe I should try out 37 signals stuff like backpack ). Another reason that has forced me from my comfort zone is that fact that I have recently been evaluating technologies for my current job and taking a cursory look at the Job market again and I have come to a conclusions of sorts. People out there like these browser based applications. Something about avoid the problems of upgrades, deployment, configuration, licensing, etc... Personally I don't see their point ;) I actually like to ram my head into walls, tables, floors, etc... So I have begun a journey to acquire some of these skills and acquaint myself with those technologies that can enable them.

A brief aside, I have not been doing monolithic applications for some time now, but it is just that my container of choice is the OSGi Java container that the Eclipse platform is based on. After learning a bit more about the Spring framework and the new Spring OSGi project, I am even more impressed with OSGi as a container and enterprisey platform architecture, but this is a digression from the current topic.

Before digging into topics like AJAX, I figured I better get more acquainted with the Java Web application world in general. I know that even though frameworks exist to make development easier, but in the end you wind up needing to at least be familiar with what is going on underneath the hood. So I began to get more familiar and see what was out there.

One more point, before I tried to begin this journey, I have been acquainted with Ruby on Rails (RoR) and its convention over configuration paradigm. "Convention over configuration" is something that I had begun to use in my own work and I immediately saw its advantages over doing everything in an XML configuration file. I was suitably impressed with the ability of RoR to generate scaffolding and allow you to have an up and running web application in minutes. I am a "lazy" ( as in the good way ) kind of person and I don't like to have to perform lots of scaffolding to get get something up. Needless to say, this was something I wanted in a web application platform that I wanted to use.

So the next obvious question is, "why not use RoR?" Good question. The answer is I am a Java developer that has been working with Java for sometime now and I don't want to have to give up all my experience just to bet it on something new, if there is a viable alternative. Second part of the answer is something I don't like about Java, lack of native integration support with legacy code (JNI (Java Native Interface) is not on my christmas card list). People out there have alot written for J2EE in Java for the web, as far as I know there is no direct way to be able to leverage this legacy stuff directly in RoR. I know that the JRuby folks are getting closer to being able to run RoR through the JVM, but they are not there yet. Even when they do, the code to interact with other Java code can be awkward. This is normal, since Ruby was developed independently and has its own ideas of what a collection, array, type is and it differs at times significantly from Java. So is there a viable alternative? I think so, the Groovy language with Grails.

Groovy
Groovy (http://groovy.codehaus.org/) is a dynamic scripting language written to be friendly to those of us coming from the statically typed Java world. Just remember that Groovy is Java, just not the Java language. Java is the title of a platform that includes the JVM, libraries and the Java language. Groovy natively sits on top of the JVM and directly uses the Java libraries, so it is a Java platform language. Visit the web site to learn more and I highly recommend the "Groovy In Action" book for you to acquaint yourself with Groovy. Groovy has the great feature of being native to the Java platform and being optionally static. Now what does Grails have to do with Groovy? Simple, Groovy is the language that a Grails application is written in. So you have a choice of learning a new language that has a completely separate syntax than you are used to ( being a Java/C++ developer ) or learn a language that is more of an extension of Java and that has most ( if not all ) the advantages of the other language? Is it really an issue? To me it wasn't, if I could find a web framework like RoR to go with it.

Grails
Groovy is all fine and dandy, but it can only do so much to help with writing Web Applications. Ruby without Rails has much the same problem, that is why the Rails framework was created. Grails is the Groovy ( and indeed Java ) world's equivalent to RoR. I have been reading the "Definitive Guide to Grails" and I find the framework very interesting. You have alot of the same advantages of RoR, namely the quick development of a simple web application, standard project structure, support for writing test suites, delineation of environments ( development, production, testing ), support for switching between databases, support for the Model-View-Controller (MVC) pattern, etc... The nice thing about it all is that in the end you have a Java based web application that can be injected directly into a servlet container like Tomcat and will seamlessly interoperate with the other web applications you have already developed.

For example to create an application in Grails you type, "grails create-app". You enter in the project name and voila, the project and its scaffolding is created for you automatically. Being an Eclipse fanboy (hey if the shoe fits... yup it does...), I like the fact that the grails application scaffolding includes a .project and .classpath file that allows me to directly import the generated grails application directly into Eclipse. The cool thing is that you can type, "grails run-app" from the project directory and you have a Jetty web server up and running your web application. You can open up a web browser and see the results immediately. This is just the sort of thing that got people all excited about RoR. Another great feature is that of dynamic loading. While running your web application in Grails with "grails create-app" you can modify the code of the application and have the results displayed in your browser by just refreshing the page. This is the sort of thing that dynamically typed languages have held over Java all this time. Now Java can have this advantage, enabling quick iterative development. This is the sort of thing that in another context, that of eclipse plugin writing, led me to write the Groovy Monkey tool.

So I have been sold, hook, line and sinker. I am going to try and write some quick blog entries over the next few days as I continue to learn Grails and highlight my progress and issues.

*Btw I have no financial interests in Grails or any of the two publications I recommended ( 'Groovy in Action' and 'The Definitive Guide to Grails' ). So take my recommendations with as much salt as you like, but at least know it is not tied to any 'check in the mail' coming to me. *Sigh*

Install Eclipse Update Sites through a Firewall

--- Came wiffling through the eclipsey wood ---
/*
 * Menu: Download > Update Site
 * Script-Path: /GroovyWebUtil/monkey/UpdateSiteDownload.em
 * Kudos: ERVIN
 * License: EPL 1.0
 * Include: /GroovyWebUtil/commons-codec-1.3.jar
 * Include: /GroovyWebUtil/commons-httpclient-3.0.1.jar
 * Include: /GroovyWebUtil/commons-logging-1.0.3.jar
 * Include-Bundle: org.apache.ant
 */

import java.io.*
import java.net.*
import org.apache.commons.httpclient.*
import org.apache.commons.httpclient.auth.*
import org.apache.commons.httpclient.methods.*
import org.apache.commons.io.*
import org.apache.commons.lang.*
import org.eclipse.core.resources.*
import org.eclipse.core.runtime.*

// Set these following 8 parameters
def featureName = 'GroovyEclipsePlugin'
def baseURL = 'http://dist.codehaus.org/groovy/distributions/update/'
def siteURL = baseURL + 'site.xml'
def baseDir = 'c:/plugins/' + featureName + '/eclipse/'

def proxyHost = 'xxxx'
def proxyPort = xx
def proxyUser = 'xxxx'
def proxyPassword = 'xxxx'

def client = new HttpClient()
client.params.setParameter( CredentialsProvider.PROVIDER, this )
client.hostConfiguration.setProxy( proxyHost, proxyPort )

FileUtils.forceMkdir( new File( baseDir ) )
FileUtils.touch( new File( baseDir + '.eclipseextension' ) )

def method = new GetMethod( siteURL )
client.executeMethod( method )

out.println 'status: ' + method.statusText + ' -> ' + siteURL

def input = method.responseBodyAsStream
def siteXML = new XmlSlurper().parse( input )
def features = siteXML.feature
def featureURLs = [ : ]
def versionMap = [ : ]
features.each
{ feature ->
 if( !versionMap.containsKey( feature.@id.text() ) )
  versionMap[ feature.@id.text() ] = feature.@version.text()
 if( versionMap[ feature.@id.text() ].compareTo( feature.@version.text() ) > 0 )
  return
 featureURLs[ feature.@id.text() ] = feature.@url
}

def ant = new AntBuilder()

def plugins = []
featureURLs.values().each
{ featureURL ->
 if( monitor.isCanceled() )
  return
 def newURL = new URL( baseURL + featureURL )
 def featureFile = baseDir + featureURL
 def destDir = StringUtils.substringBeforeLast( featureFile, '.' )
 FileUtils.forceMkdir( new File( destDir ) )
 FileUtils.copyURLToFile( newURL, new File( featureFile ) )
 ant.unzip( src: featureFile, dest: destDir )
 ant.delete( file: featureFile )
 def featureXMLText = new File( destDir + '/feature.xml' ).text
 def featureXML = new XmlSlurper().parseText( featureXMLText )
 featureXML.plugin.depthFirst().collect{ plugins.add( it ) }
}

monitor.beginTask( 'Starting downloads', plugins.size() + 1 )
plugins.each
{ plugin ->
 if( monitor.isCanceled() )
  return
 def pluginJar = "${plugin.@id}_${plugin.@version}.jar"
 def newURL = new URL( baseURL + 'plugins/' + pluginJar )
 def pluginFile = baseDir + 'plugins/' + pluginJar
 def destDir = StringUtils.substringBeforeLast( pluginFile, '.' )
 FileUtils.forceMkdir( new File( destDir ) )
 if( new File( pluginFile ).exists() )
  return
 FileUtils.copyURLToFile( newURL, new File( pluginFile ) )
 if( plugin.@unpack.text().trim().toLowerCase() != 'false' )
 {
  ant.unzip( src: pluginFile, dest: destDir )
  ant.delete( file: pluginFile )
 }
}

--- And burbled as it ran! ---

  --- Came wiffling through the eclipsey wood ---
  /*
   * Menu: Download > Update Site
   * Script-Path: /GroovyMonkeyScripts/monkey/UpdateSiteDownload.gm
   * Kudos: ERVIN
   * License: EPL 1.0
   * DOM: http://groovy-monkey.sourceforge.net/update/plugins/net.sf.groovyMonkey.dom
   * Include: /GroovyMonkeyScripts/commons-codec-1.3.jar
   * Include: /GroovyMonkeyScripts/commons-httpclient-3.0.1.jar
   * Include: /GroovyMonkeyScripts/commons-logging-1.1.jar
   * Include-Bundle: org.apache.ant
   */
  
  import java.io.*
  import java.net.*
  import org.apache.commons.httpclient.*
  import org.apache.commons.httpclient.auth.*
  import org.apache.commons.httpclient.methods.*
  import org.apache.commons.io.*
  import org.apache.commons.lang.*
  import org.eclipse.core.resources.*
  import org.eclipse.core.runtime.*
  
  // Set these following 8 parameters
  def featureName = 'GroovyEclipsePlugin'
  def baseURL = 'http://dist.codehaus.org/groovy/distributions/update/'
  def siteURL = baseURL + 'site.xml'
  def baseDir = 'c:/plugins/' + featureName + '/eclipse/'
  
  def proxyHost = 'xxxx'
  def proxyPort = xx
  def proxyUser = 'xxxx'
  def proxyPassword = 'xxxx'

  def client = new HttpClient()
  client.params.setParameter( CredentialsProvider.PROVIDER, this )
  client.hostConfiguration.setProxy( proxyHost, proxyPort )

  FileUtils.forceMkdir( new File( baseDir ) )
  FileUtils.touch( new File( baseDir + '.eclipseextension' ) )
  def method = new GetMethod( siteURL )
  client.executeMethod( method )
  out.println 'status: ' + method.statusText + ' -> ' + siteURL
  
  def input = method.responseBodyAsStream
  def siteXML = new XmlSlurper().parse( input )
  def features = siteXML.feature
  def featureURLs = [ : ]
  def versionMap = [ : ]
  features.each
  { feature ->
    if( !versionMap.containsKey( feature.@id.text() ) )
      versionMap[ feature.@id.text() ] = feature.@version.text()
    if( versionMap[ feature.@id.text() ].compareTo( feature.@version.text() ) > 0 )
      return
    featureURLs[ feature.@id.text() ] = feature.@url
  }
  
  def ant = new AntBuilder()
  def plugins = []
  featureURLs.values().each
  { featureURL ->
    if( monitor.isCanceled() )
      return
    def newURL = new URL( baseURL + featureURL )
    def featureFile = baseDir + featureURL
    def destDir = StringUtils.substringBeforeLast( featureFile, '.' )
    FileUtils.forceMkdir( new File( destDir ) )
    FileUtils.copyURLToFile( newURL, new File( featureFile ) )
    ant.unzip( src: featureFile, dest: destDir )
    ant.delete( file: featureFile )
    def featureXMLText = new File( destDir + '/feature.xml' ).text
    def featureXML = new XmlSlurper().parseText( featureXMLText )
    featureXML.plugin.depthFirst().collect{ plugins.add( it ) }
  }
  
  monitor.beginTask( 'Starting downloads', plugins.size() + 1 )
  plugins.each
  { plugin ->
    if( monitor.isCanceled() )
      return
    def pluginJar = "${plugin.@id}_${plugin.@version}.jar"
    def newURL = new URL( baseURL + 'plugins/' + pluginJar )
    def pluginFile = baseDir + 'plugins/' + pluginJar
    def destDir = StringUtils.substringBeforeLast( pluginFile, '.' )
    if( new File( pluginFile ).exists() )
      return
    FileUtils.copyURLToFile( newURL, new File( pluginFile ) )
    out.println "${plugin.@id}: unpack=${plugin.@unpack.text()}"
    if( plugin.@unpack.text().trim().toLowerCase() == 'false' )
     return
    FileUtils.forceMkdir( new File( destDir ) )
   ant.unzip( src: pluginFile, dest: destDir )
   ant.delete( file: pluginFile )
  }
  
  --- And burbled as it ran! ---

Want to be able to download eclipse plugins, but the firewall wont let you?

Having trouble getting the eclipse update mechanism to tunnel through the firewall, but port 80 is open through http?

If you have Groovy Monkey installed and include the commons-codec-1.3.jar, commons-httpclient-3.0.1.jar and commons-logging-1.0.3.jar libraries in your workspace, use the script above. Define the 8 parameters and the script should download the update package from the url that the update manager should connect to. The script then packages it as the appropriate set of plugins ( zipped or unzipped ) based on the feature.xml and then deploys it to a directory that you can define and creates an extension location that Eclipse can directly import.

In the script above I downloaded the Groovy Eclipse plugin from the update site and had it packaged into the /plugins/GroovyEclipse/eclipse directory as an extension location. I like to separate my plugins like this. The last step is after the script runs successfully goto "Help -> Software Updates -> Manage Configuration" and open the manage configuration dialog. Right click on the root node "Eclipse SDK" and select "Add -> Extension Location". Navigate to the location where the plugin was installed, in the above case /plugins/GroovyEclipse/eclipse, and then click ok. Eclipse will install the plugin and probably ask to restart. You are done...

Version 0.4.0 is released

I have released the latest version of Groovy Monkey with the following new features:

Version 0.4.0 - December 24, 2006

• Added autocomplete for binding variables.


• Added method autocompletion for bound variables.


• Now can publish to clipboard directly from the editor.


• Added a "Save Script To" dialog to allow the user to select where in their workspace they want the script written.

I am also in the process of merging Groovy Monkey with the original Eclipse Monkey, so future work maybe accomplished over there.

Quickly remove unwanted markers in your workspace.

I have been asked, "Groovy Monkey why?" Now there are the default answers of API exploration, Eclipse Automation and rapid prototyping, however, now I have a new one: "You think someone will bother to write a plugin to do that?" The following example highlights this feature.

Here is a quick script written whilest I was debugging the Groovy Eclipse Plugin. The problem I had was that the plugin left some markers lying around that I don't want to see anymore.

So you can use this script to parse through your Eclipse workspace and find all the problem markers and then choose to delete those that don't apply anymore. I think it is pretty useful when you are working on plugins or if you downloaded a particularly buggy plugin. Sure does beat shutting down Eclipse, then opening up the $workspace/.metadata/org.eclipse.core.resources/.projects/$projectname/ and then manually deleting any .markers files you find.

To import the script into Eclipse follow the following steps.
First you must have installed Groovy Monkey.

Secondly, then you must select all the text below ( starting with '--- Came wiffling...' and copy it into your clipboard on your browser (Ctrl-C usually works).

Now goto eclipse and under the Groovy Monkey menu select 'Paste New Script'.

Voila it will be incorporated into your workspace and can be run as 'Groovy Monkey > Remove Markers'. Enjoy.

--- Came wiffling through the eclipsey wood ---
/*
 * Menu: Remove Markers
 * Script-Path: /GroovyMonkeyScripts/monkey/removeMarkers.gm
 * Kudos: ERVIN
 * License: EPL 1.0
 * DOM: http://groovy-monkey.sourceforge.net/update/plugins/net.sf.groovyMonkey.dom
 */
import org.eclipse.core.resources.*

out.clear()
workspace.root.projects.each
{ project ->
 out.println "${project.name}"
 project.findMarkers( null, true, IResource.DEPTH_INFINITE ).each
 { marker ->
  out.println "  ** ${marker.type} ${marker.id} ${marker.attributes}"
  if( marker.type == 'org.codehaus.groovy.eclipse.groovyFailure' )
   marker.delete()
 }
}

--- And burbled as it ran! ---

Version 0.3.0 of Groovy Monkey released

I am just putting all the packaging in place for the latest version of Groovy Monkey, version 0.3.0. By the way, I am not putting a whole lot of meaning behind the version numbers, 0.2.0 was chosen before since it was originally a port of Eclipse Monkey and it was at version 0.1.5 or something. The following is noteworthy:

Version 0.3.0 - September 11, 2006

• Changed the Groovy Monkey default project name to GroovyMonkeyScripts as per issue: [ 1536760 ] Change GroovyMonkeyExamples to GroovyMonkeyScripts


• Added an Include-Bundle dialog to the editor context menu, to the Package Explorer view and Navigator.


• Added Include and Include-Bundle dialogs to Groovy Editor context menu command set.


• Added a Java search, modeled on the PDE search, to the outline view to look for all the classes exposed from an included bundle in the set of exported packages. So if your 'External Plug-in Libraries' project is setup, you should see the classes.


• Added a Script-Path: metadata tag that is automatically maintained by Groovy Monkey, it is set to the workspace path of the script.


• The Script Outline view now has menu commands to switch between Flat/Hierarchical views of the binding.


• There are now error markers signifying some command errors with script metadata and some quick fixes to assist.


• There is now some content assist on the Script Metadata tags.


• A new submenu of the top level 'Groovy Monkey' has been added called 'Edit Script'. The Edit Script submenu reflects the top menu, but instead of launching the scripts, it opens the editor for you.


• Added Hippie completion to the editor.


• Added ability to map dom vars to different names for the local script, enables solution for variable name conflicts between DOM plugins.

Groovy Monkey: Eclipse Icons Script Pt 4/4: Rapid Prototyping with DOM Plugins

In the first and second postings of this series I showed how to implement a script that checks out the icons folders from all of the Eclipse Projects from the CVS server at dev.eclipse.org. The third installment had to do with breaking up and using library scripts through the Runner DOM to create code reuse and refactoring. This installment will now attempt to do what the third did, but with a prototype DOM plugin developed right in the workspace of your current Eclipse instance. The part I think that is exciting is that we will write a plugin and then use some simple Groovy Monkey scripts to dynamically update the DOM from within the current running Eclipse instance without restarting the workbench. Before I continue, one note of caution, this is still a bit of a work in progress. The plugins that will be dynamically swapped out are the simple type that you would use as a DOM and shouldn't contain much in the way of state, unless you are going through the trouble to make sure that you can hotswap out your plugins. The subject of how to make your plugins hotswappable is a whole subject onto itself, so we are going to sidestep it by keeping the DOM plugins simple.

This article is going to take you step by step through an example using the getEclipseIcons.gm script that was developed in previous articles in this series and the IncludeLocalBundle PDE JUnit test case that I wrote in net.sf.groovyMonkey.tests.

So to begin lets start with the example script that was created before we modified it to use library scripts in the last posting.

--- Came wiffling through the eclipsey wood ---
/*
* Menu: Get Eclipse Icons
* Kudos: ervinja
* License: EPL 1.0
* DOM: http://groovy-monkey.sourceforge.net/update/plugins/net.sf.groovyMonkey.dom
* Include-Bundle: org.eclipse.team.cvs.core
* Include-Bundle: org.eclipse.team.cvs.ui
*/
import org.eclipse.core.resources.IProject
import org.eclipse.core.resources.IResource
import org.eclipse.core.runtime.SubProgressMonitor
import org.eclipse.team.internal.ccvs.core.CVSProviderPlugin
import org.eclipse.team.internal.ccvs.core.ICVSRemoteFolder
import org.eclipse.team.internal.ccvs.ui.operations.CheckoutIntoOperation
import org.eclipse.team.internal.ccvs.ui.operations.DisconnectOperation

// Here we find the desired repository location that has already been configured
//  in the CVS Respository Explorer.
def plugin = CVSProviderPlugin.getPlugin()
def repositoryLoc
for( location in plugin.getKnownRepositories() )
{
     if( monitor.isCanceled() )
                return
        if( location.getRootDirectory() == '/home/eclipse' )
                repositoryLoc = location
}

// Here we query all the remote repository top level projects for sub-folders
//  called icons and then store them into a list for later use.
def members = repositoryLoc.members( null, false, null )
monitor.beginTask( '', 2 * members.size() )
def iconFolders = []
for( member in members )
{
    member.fetchChildren()
    if( monitor.isCanceled() )
               return
    if( !member.childExists( 'icons' ) )
    {
        monitor.worked( 1 )
               continue
    }
       def icons = member.getFolder( 'icons' )
    iconFolders.add( icons )
    monitor.worked( 1 )
}

// Check out those icon folders under a sub-folder of the target project called
//  icons and place each remote icon folder in a sub-folder of icons that corresponds
//  to its project name.
def targetProject = workspace.getRoot().getProject( 'GroovyMonkeyExamples' )
iconFolders.each
{ folder ->
    if( monitor.isCanceled() )
        return
        def targetFolder = targetProject.getFolder( 'icons' ).getFolder( folder.getRemoteParent().getRepositoryRelativePath() )
    new CheckoutIntoOperation( null, folder, targetFolder, true ).execute( new SubProgressMonitor( monitor, 1 ) )
    monitor.worked( 1 )
}

// Clear off the CVS cruft.
jface.syncExec
{
        new DisconnectOperation( null, [ targetProject ].toArray( new IProject[0] ), true ).run()
}

// Build the eclipse-icons.zip file using AntBuilder
def baseDir = targetProject.getFolder( 'icons' )
def destFile = targetProject.getFile( 'eclipse-icons.zip' )
if( destFile.exists() )
        destFile.delete( true, null )

def ant = new AntBuilder()
ant.zip( basedir:"${baseDir.getRawLocation()}", destfile:"${destFile.getRawLocation()}" )

// Refresh the targetProject so that eclipse-icons.zip shows up in the Navigator and Package Explorer.
targetProject.refreshLocal( IResource.DEPTH_INFINITE, null )

monitor.done()
--- And burbled as it ran! ---

We want to create a DOM that can wrap calls to Eclipse's CVS API and provide a simplified interface for our scripts. One definite advantage to doing this is that we can develop the DOM plugin using the PDE and all of the wonderous advantages of the JDT Editor like autocompletion and the like. Another is that while the Runner DOM is useful, there is nothing like being able to make a direct method call on an object for clarity.

Setup DOM Plugin Project: net.sf.groovyMonkey.dom.cvs

The first step is that we need an Eclipse Project in our workspace in which to begin work on this new DOM. Of course this is a plugin project, so we use the 'New Plug-in Project' wizard. I name this project net.sf.groovyMonkey.dom.cvs since I am working on Groovy Monkey projects, however, you can name it whatever you like. I use all the default settings and avoid using the templates since Groovy Monkey does not have a wizard for creating a DOM Plugin Project. Of course, there is nothing that says that your DOM cannot have UI elements and therefore you might choose to use a template for your project, but at this time I am electing for simplicity.

After we have our project in the workspace, we must do some configuration work.

First make your plugin depend upon the net.sf.groovyMonkey plugin project by opening the Manifest editor and adding it to the list of required plugins.

Second add an extension of the extension point net.sf.groovyMonkey.dom using the Extensions page of the Manifest editor. Right click the net.sf.groovyMonkey.dom extension in the view and select 'New > updateSite'. This is what is used to display your DOM in the Outline view of the Groovy Monkey editor and the InstalledDOMs view. If you don't know exactly what it should be yet, this is fine, just select something that is likely to make sense. In my case I put in 'http://groovy-monkey.sourceforge.net/update/net.sf.groovyMonkey.dom.cvsdom'. To be honest I have yet to really use update sites to update my DOM plugins, so don't be surprised if it does not quite work. I tend to use the DOM plugins in my workspace and also have a default set of doms that come with Groovy Monkey included. If you try and it does/doesn't work, drop me a line ( jervin@completecomputing.com ) and let me know the results. As you will see from what follows, it may not be completely necessary.

Next right click the net.sf.groovyMonkey.dom node again and this time select 'New > dom'. Under this new node you see a few fields to fill in and we will go through them one by one.

1. The first field is variableName and it is required. The variableName field is the name under which your dom will be put in the scripts binding, so it is important to select something easy to type and more importantly a name that is relatively unique. I know that the uniqueness part is a bit tricky and perhaps this is something that could use a tool to enhance or help. At the very least a warning in the Error Log that Eclipse has a DOM Plugins that define variables of the same name. Of course conflicting names may not be a problem if your scripts do not reference the DOMs with the same variable name. In this case I use cvsDOM. I am using the DOM postfix convention, so as to hopefully leave the binding and the script namespace relatively clean. Even if you should override the variable name inside your script's scope, you can use the bsf ( never override ) variable to access the BSFFunctions class which can allow you to look up the bound object by name.
   
2. The next field specifies the class that will implement the IMonkeyDOMFactory interface to create instances of the DOM objects that the script will use. I click the class link and use the wizard to create a class called DOMFactory in the net.sf.groovymonkey.dom.cvsdom package that implements IMonkeyDOMFactory. I am not using a name like CVSDOMFactory since I think that the package that it exists in is obvious enough and I am not going to put another DOM object in that package, for now at least.
   
3. The next field called 'id' is an optional field where you can put a human friendly name on this DOM, I think 'CVS DOM' is friendly enough.
   
4. Finally there is the optional field called 'resource' and it is used to have you enter in the full class name of the object that the DOM Factory is supposed to return in the method getDOMRoot(). This field is preferred by the Groovy Monkey Outline page to assist the user in knowing what types and methods they have available. So it is highly recommended that you set it, since otherwise the Outline page content provider will call getDOMRoot() and perform reflection on it to determine what is being returned. It is kind of hard to know what to put in there before we create it, so we leave it blank for now.

Now we have the class DOMFactory that has a constructor and a method called getDOMRoot(). It is probably best practice to not do too much in the constructor and indeed in this class in general, since it could be instanciated numberous times and getDOMRoot() could be invoked a number of times from outside the context of the script. One thing though, do not return null from the getDOMRoot() method. So to make life easier on me, I create the class net.sf.groovymonkey.dom.cvs.CVSDOM and have the getDOMRoot() method just return a new instance of this class. Now that we have the type, go back to the manifest editor and put in that value into the resource field. Believe it or not we are now done with both the manifest editor and the DOM Factory class. This is all the scaffolding that is needed to put a DOM from a plugin into Groovy Monkey. Groovy Monkey searches for all net.sf.groovyMonkey.dom extensions and then grabs all the information we provided. You could in fact already use this as a plugin for your Eclipse workbench, of course the DOM object doesn't do anything yet, but that is beside the point, right? ;) You could use self hosting and make sure that the Groovy Monkey plugins are used in the runtime instance and check it out for yourself, but that is alot of trouble no and I said I will show you how to do it without headaches.

Setup Project to be loaded at will in current Eclipse Workspace

I just made a strong claim, that you can already install this DOM in your workbench and use it. It is an even stronger claim given that I made the promise that I will show you how to do it dynamically and without restarting your workbench and without having to spawn a self hosted runtime workbench instance. To make this promise come true, we are going to have to do a few things.

1. Create a monkey folder, for a script I am going to provide, under the project, in my case net.sf.groovyMonkey.dom.cvs.
2. Create a lib folder for the library scripts I am going to provide.
3. Copy the following script into your clipboard and use the 'Groovy Monkey > Paste New Script' menu command to put it into your workspace. You are going to have to move it to your project under the monkey folder manually, perhaps there is an opportunity for an enhancement here. I put in under my net.sf.groovyMonkey.dom.cvs project under the monkey folder and called it installDOM.gm.

--- Came wiffling through the eclipsey wood ---
/*
 * Menu: Install/Update > CVS DOM
 * Kudos: James E. Ervin
 * License: EPL 1.0
 * DOM: http://groovy-monkey.sourceforge.net/update/net.sf.groovyMonkey.dom
 */
import java.io.File
import org.apache.commons.io.FileUtils

def plugin = 'net.sf.groovyMonkey.dom.cvs'

// If this bundle is already installed, remove it
runnerDOM.runScript( "${plugin}/lib/uninstall.gm", [ pluginToUninstall:plugin ] )

// Build and export the bundle jar
bundlerDOM.createDeployDir()
jface.syncExec
{
    bundlerDOM.buildPluginJar( workspace.getRoot().getProject( plugin ) )
}

// Grab the current version of the plugin to be able to identify the jar file.
def bundleVersion = runnerDOM.runScript( "${plugin}/lib/getBundleVersion.gm", [ 'plugin':plugin ] )

// Install and start the new bundle.
def context = bundleDOM.context()
def installedBundle = context.installBundle( "file:" + bundlerDOM.getDeployDir() + "/plugins/" + plugin + "_" + bundleVersion + ".jar" )
installedBundle.start()

--- And burbled as it ran! ---

* Note: If you are not calling your project 'net.sf.groovyMonkey.dom.cvs' remember to change the plugin variable above to the correct project name.
** Note: Be real careful with bunderDOM. By default it wants to deploy plugins to '/tmp/deployedBundles/plugins' and will want to delete and recreate the directory each time you call createDeployDir() on it. I forgot about this and set the deploy dir to my eclipse install plugins directory and *really* regretted it.
*** Note: When you restart eclipse, since the path '/tmp/deployedBundles' is not an Eclipse Extension Location, it be loaded when eclipse is restarted. I think while you are developing a DOM plugin this could be a feature, however, if you want it to persist just copy it from the deploy directory ( default: '/tmp/deployedBundles/plugins' ) to an Eclipse Extension Location or easier yet, into your Eclipse Install plugins directory.

4. Copy the following script into the clipboard and use the 'Groovy Monkey > Paste New Script' menu command to place it into your workspace. Once again move it manually into the project under the lib folder. There is a difference here, since the script above makes a call on it by directly referencing it as uninstall.gm, it is important you name it as such or you go back and change the installDOM.gm script to refer to the correct library script. I put it into my net.sf.groovyMonkey.dom.cvs project under lib and with the name uninstall.gm.

--- Came wiffling through the eclipsey wood ---
/*
 * Kudos: James E. Ervin
 * License: EPL 1.0
 * DOM: http://groovy-monkey.sourceforge.net/update/net.sf.groovyMonkey.dom
 */
import org.apache.commons.lang.Validate

Validate.notNull( bsf.lookupBean( 'pluginToUninstall' ), 'pluginToUninstall must be set' )

for( plugin in bundleDOM.context().getBundles() )
{
    if( plugin.getSymbolicName().equals( pluginToUninstall ) )
        plugin.uninstall()
}
--- And burbled as it ran! ---

5. Once again copy the following script into the clipboard and use the 'Groovy Monkey > Paste New Script' menu command to place it into your workspace. Move it manually into the project under the lib folder. Since the main script makes a call on it by directly referencing it as getBundleVersion.gm, it is important you name it as such or you go back and change the installDOM.gm script to refer to the correct library script. I put it into my net.sf.groovyMonkey.dom.cvs project under lib and with the name getBundleVersion.gm.

--- Came wiffling through the eclipsey wood ---
/*
 * Kudos: James E. Ervin
 * License: EPL 1.0
 * DOM: http://groovy-monkey.sourceforge.net/update/net.sf.groovyMonkey.dom
 */
import java.util.jar.Manifest
import org.apache.commons.lang.Validate

Validate.notNull( bsf.lookupBean( 'plugin' ), 'plugin must be set' )

def file = workspace.getRoot().getProject( plugin ).getFile( 'META-INF/MANIFEST.MF' )
def input = file.getContents()
try
{
    def manifest = new Manifest( input )
    def attributes = manifest.getMainAttributes()
    return attributes.getValue( 'Bundle-Version' )
}
finally
{
    input.close()
}

--- And burbled as it ran! ---

6. Just to be able to show that it works as expected, bring up the 'Installed DOMs' view by 'Window > Show View > Other > Groovy Monkey > Installed DOMs'. Look at the list, unless you have done some other work before following this script, it should not include an entry for your project, in my case no net.sf.groovyMonkey.dom.cvs DOM plugin installed.

Run the script installDOM.gm either by right click menu command 'Run Script' from the Groovy Monkey Editor or by 'Groovy Monkey > Install > CVS DOM'. Now go back to the 'Installed DOMs' view and it should be there. Go ahead and write a quick script to check it out if you like, of course we haven't added anything to it yet.

Start work on CVS DOM object

Well the initial idea is to replace sections of the original getEclipseIcons.gm script with method calls on this new CVS DOM object. So lets add a method called getKnownRepository that takes the arguments of the script that we used to refactor the script in the last article. To accomplish this we will have to add org.eclipse.team.cvs.core bundle as a Required Plug-in in the manifest editor. The code is as follows:

package net.sf.groovymonkey.dom.cvsdom;
import static org.eclipse.team.internal.ccvs.core.CVSProviderPlugin.getPlugin;
import org.eclipse.team.internal.ccvs.core.ICVSRepositoryLocation;

public class CVSDOM
{
    public ICVSRepositoryLocation getKnownRepository( final String locationString )
    {
        for( ICVSRepositoryLocation location : getPlugin().getKnownRepositories() )
        {
            if( location.getLocation( true ).equals( locationString ) )
                return location;
        }
        return null;
    }
}

* Note: I am using Java 5.0 for this example and if you are running Groovy Monkey, your Eclipse instance needs to be run in Java 5.0 too. This should not be a large problem since Eclipse can be run with one JRE install, but your code that you are developing can be run with another. There are also all sorts of nice settings in the JDT to allow you to use Java 5.0, but force the code to be valid for 1.4, 1.3, etc...
** Note: Of course you can rewrite this to be 1.4 compliant if you wish.
*** Note: Lastly remember that since your DOM will not be invoked in a seperate thread ( i.e. Eclipse Job ), if you suspect that the operation will take too long, by all means pass in a progress monitor to the method and make use of it.

Now that is kind of neat, so lets use this. What we can't? The other version of the DOM was installed first? Well try running the 'Groovy Monkey > Install > CVS DOM' feature again. Now go back to the 'Installed DOMs' view, does it look the same? Open up the cvsDOM node, open up the CVSDOM class node and now check the listed methods. Your new getKnownRepository() method now shows up.

For people who have been working with Eclipse and developing plugins, this should pique your interest. We are using the OSGi runtime as it was intended, we hotswapped out our net.sf.groovyMonkey.dom.cvs plugin at runtime. If you keep the DOM plugin simple, this should work again and again, with no need to restart the workbench or having to mess with version numbers. To learn more about this goto OSGi and get a copy of the specification.

So now to use it in our script, we open up the getEclipseIcons.gm script in our Groovy Monkey Editor and then right click to bring up the menu option 'Add DOM to Script'. Select the new DOM to be added, in my case here it is net.sf.groovyMonkey.dom.cvs, and click ok. Now rewrite the following section of the script:

// Here we find the desired repository location that has already been configured
//  in the CVS Respository Explorer.
def plugin = CVSProviderPlugin.getPlugin()
def repositoryLoc
for( location in plugin.getKnownRepositories() )
{
    if( monitor.isCanceled() )
        return
    if( location.getRootDirectory() == '/home/eclipse' )
        repositoryLoc = location
}

as:

// Here we find the desired repository location that has already been configured
//  in the CVS Respository Explorer.
def cvsRepository = ':pserver:anonymous@dev.eclipse.org:/home/eclipse'
def repositoryLoc = cvsDOM.getKnownRepository( cvsRepository )
Validate.notNull( repositoryLoc, "Error could not find the repository ${cvsRepository}, has it been added to the CVS Repository Explorer?" )

The last part just makes sure that the value is not null as a check.

You can continue on to replace the other sections of code with the DOM. Down below is the final version of the class:

package net.sf.groovymonkey.dom.cvsdom;
import static org.eclipse.core.runtime.SubProgressMonitor.PREPEND_MAIN_LABEL_TO_SUBTASK;
import static org.eclipse.swt.widgets.Display.getCurrent;
import static org.eclipse.swt.widgets.Display.getDefault;
import static org.eclipse.team.internal.ccvs.core.CVSProviderPlugin.getPlugin;
import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.lang.StringUtils;
import org.eclipse.core.resources.IFolder;
import org.eclipse.core.resources.IProject;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.team.internal.ccvs.core.CVSException;
import org.eclipse.team.internal.ccvs.core.ICVSRemoteFolder;
import org.eclipse.team.internal.ccvs.core.ICVSRemoteResource;
import org.eclipse.team.internal.ccvs.core.ICVSRepositoryLocation;
import org.eclipse.team.internal.ccvs.core.resources.RemoteFolder;
import org.eclipse.team.internal.ccvs.ui.operations.CheckoutIntoOperation;
import org.eclipse.team.internal.ccvs.ui.operations.DisconnectOperation;

public class CVSDOM
{
    public ICVSRepositoryLocation getKnownRepository( final String locationString )
    {
        for( ICVSRepositoryLocation location : getPlugin().getKnownRepositories() )
        {
            if( location.getLocation( true ).equals( locationString ) )
                return location;
        }
        return null;
    }
    public List<> getRepositoryResources( final IProgressMonitor progressMonitor,
                                                              final ICVSRepositoryLocation location,
                                                              final String subfolder )
    throws CVSException
    {
        final IProgressMonitor monitor = progressMonitor == null ? new NullProgressMonitor() : progressMonitor;
        final List<> folders = new ArrayList<>();
        final ICVSRemoteResource[] members = location.members( null, false, null );
        monitor.beginTask( "Getting Remote CVS Resources", members.length );
        for( final ICVSRemoteResource member : members )
        {
            if( monitor.isCanceled() )
                return null;
            monitor.subTask( member.getName() );
            final RemoteFolder folder = ( RemoteFolder )member;
            folder.fetchChildren( new SubProgressMonitor( monitor, PREPEND_MAIN_LABEL_TO_SUBTASK ) );
            if( StringUtils.isBlank( subfolder ) )
            {
                folders.add( member );
                monitor.worked( 1 );
                continue;
            }
            if( !folder.childExists( subfolder ) )
            {
                monitor.worked( 1 );
                continue;
            }
            folders.add( ( ICVSRemoteResource )folder.getFolder( subfolder ) );
            monitor.worked( 1 );
        }
        monitor.done();
        return folders;
    }
    public CVSDOM checkOut( final IProgressMonitor progressMonitor,
                            final List<> remoteResources,
                            final IFolder target,
                            final boolean disconnect )
    throws CVSException, InterruptedException, InvocationTargetException
    {
        final IProgressMonitor monitor = progressMonitor == null ? new NullProgressMonitor() : progressMonitor;
        monitor.beginTask( "Checking out into target: " + target.getFullPath(), remoteResources.size() );
        for( final ICVSRemoteResource folder : remoteResources )
        {
            if( monitor.isCanceled() )
                return this;
            if( !( folder instanceof ICVSRemoteFolder ) )
                continue;
            final IFolder targetFolder = target.getFolder( folder.getRemoteParent().getRepositoryRelativePath() );
            new CheckoutIntoOperation( null, ( ICVSRemoteFolder )folder, targetFolder, true ).execute( new SubProgressMonitor( monitor, 1 ) );
            monitor.worked( 1 );
        }
        if( !disconnect )
            return this;
        disconnect( target.getProject() );
        monitor.done();
        return this;
    }
    public CVSDOM disconnect( final IProject project )
    {
        if( getCurrent() == null )
        {
            final Runnable runnable = new Runnable()
            {
                public void run()
                {
                    disconnect( project );
                }
               
            };
            getDefault().syncExec( runnable );
            return this;
        }
        try
        {
            new DisconnectOperation( null, new IProject[] { project }, true ).run();
        }
        catch( final InvocationTargetException e )
        {
            throw new RuntimeException( e );
        }
        catch( final InterruptedException e )
        {
            throw new RuntimeException( e );
        }
        return this;
    }
}

Now here is the final version of the script to the new DOM:

--- Came wiffling through the eclipsey wood ---
/*
 * Menu: Get Eclipse Icons > Refactored DOM
 * Kudos: ervinja
 * License: EPL 1.0
 * DOM: http://groovy-monkey.sourceforge.net/update/plugins/net.sf.groovyMonkey.dom
 * Include-Bundle: org.eclipse.team.cvs.core
 * Include-Bundle: org.eclipse.team.cvs.ui
 * DOM: http://groovy-monkey.sourceforge.net/update/net.sf.groovyMonkey.dom.cvs
 */
import org.apache.commons.lang.Validate
import org.eclipse.core.resources.IResource
import org.eclipse.core.runtime.SubProgressMonitor

// Here we find the desired repository location that has already been configured
//  in the CVS Respository Explorer.
def cvsRepository = ':pserver:anonymous@dev.eclipse.org:/home/eclipse'
def repositoryLoc = cvsDOM.getKnownRepository( cvsRepository )
Validate.notNull( repositoryLoc, "Error could not find the repository ${cvsRepository}, has it been added to the CVS Repository Explorer?" )

// Here we query all the remote repository top level projects for sub-folders
//  called icons and then store them into a list for later use.
def iconFolders = cvsDOM.getRepositoryResources( new SubProgressMonitor( monitor, 1 ), repositoryLoc, 'icons' )
if( iconFolders == null )
    return

// Check out those icon folders under a sub-folder of the target project called
//  icons and place each remote icon folder in a sub-folder of icons that corresponds
//  to its project name.
def targetProject = workspace.getRoot().getProject( 'GroovyMonkeyExamples' )
cvsDOM.checkOut( new SubProgressMonitor( monitor, 1 ), iconFolders, targetProject.getFolder( 'icons' ), true )

// Build the eclipse-icons.zip file using AntBuilder
def baseDir = targetProject.getFolder( 'icons' )
def destFile = targetProject.getFile( 'eclipse-icons.zip' )
if( destFile.exists() )
    destFile.delete( true, null )
def ant = new AntBuilder()
ant.zip( basedir:"${baseDir.getRawLocation()}", destfile:"${destFile.getRawLocation()}" )
// Refresh the targetProject so that eclipse-icons.zip shows up in the Navigator and Package Explorer.
targetProject.refreshLocal( IResource.DEPTH_INFINITE, null )
monitor.done()
--- And burbled as it ran! ---

If we like the results, we can then deploy the DOM plugin for real to an update site for others to use. Once I figure out a little bit more of this blog API and figure out how to upload files, I will include the source files for the scripts and the net.sf.groovyMonkey.dom.cvs DOM plugin.

I hope once again this has proven helpful and will encourage you to experiment more with Eclipse using Groovy Monkey.