I’m so amazed when I see how so few companies are using Groovy and Grails right now, and are still using old stuff like Spring and Hibernate, that I thought I would jump in and do my share of educating. And why not give in to the fashion of top lists while I’m at it? So here it goes: if you are an enterprise software architect and you have a lot of Java in your world, you might want to read carefully what follows.
One of the main goals I’ve been pursuing for a few months is the integration of Grails with Flex 4. I need to rework ConferenceGuide‘s administration backend to make it more ergonomic so that we can cover more events, and ever since I discovered Flex 4 niceties, I couldn’t think of doing that with anything else. The problem is that none of the existing plugins suited my needs. All of them cover Flex 3 only, some of them introduce a lot of complexity for CRUD generation, some of them use GraniteDS instead of BlazeDS, and the simplest plugin, grails-flex has never gone further than the experimental stage. I did a lot of experiments, talked a lot about it on Grails mailing lists, until Tomas Lin kindly explained to me that maybe I was approaching it the wrong way. I wanted a plugin that would set up a complete environment for Flex developement right in the middle of my Grails application. And I wanted that because I wanted to avoid using Flash Builder (you know… Eclipse… ierk!), mainly because the only advantage of Flex Builder 3 over IntelliJ Idea was the visual designer. But he was right, I was wrong. Flash Builder 4 DOES change everything. It does include a lot of very interesting features that greatly improve Flex development productivity, especially when it comes to integration with backend technologies. And for those features, I can only admit that IntelliJ is not up to par yet. I’m still gonna use it for the Grails part, but Flash Builder will be my environment of choice for Flex 4.
So, once I learnt more about Flex 4, BlazeDS 4 and Flash Builder 4 beta 2, it was time to reconsider my approach and develop a much simpler Grails plugin so that any Grails application could be used in combination with Flash Builder. I just released grails-blazeds plugin to do just that. Here is how it works:
- Install grails-blazeds plugin: “grails install-plugin blazeds”. This plugin copies a couple of configuration files into your application and imports all of the required libraries, including BlazeDS 4 and Spring-BlazeDS integration 1.5, both in nightly snapshot versions, since they have not been officially released yet
- Create a service to be exposed to your Flex application over AMF, or choose an existing one
- Add @RemotingDestination annotation to your service class, and @RemotingInclude annotation to all of the methods in this service that you wish to expose
- Edit web-app/WEB-INF/flex-servlet.xml (created when you installed the plugin): uncomment the context:component-scan element and set the base-package corresponding to your service class
- Make sure your exposed service methods don’t use Groovy classes, either as argument or return types. This is a known limitation I’m still working on, but if there are some Groovy classes here, Flash Builder doesn’t manage to generate ActionScript counterparts.
- Run your Grails application using “grails run-war” instead of “grails run-app”. Once again this is a known limitation: Flash Builder BlazeDS data connection plugin relies on a classical web app layout and doesn’t understand Grails dynamic layout (that is until someone manages to create a Grails data connection wizard for Flash Builder 4)
- In Flash Builder 4 beta 2, create a new Flex project with a J2EE server. Here are what your parameters shoud look like, “conferenceguide” being the name of my Grails application and “sarbogast” being my home directory:
- Click “Data” menu, then “Connect to BlazeDS…”
- In the “Authentication required” dialog box that appears, check “no password required” box, and click OK
- You should see your service appear, and you can select it and click Finish.
- Your service should appear in the Data/Services view. You can then compose your user interface and drag and drop your service methods to the relevant components to connect them with your Grails backend.
- Don’t forget to configure a channelset on your service:
<adminservice:AdminService id="adminService" fault="Alert.show(event.fault.faultString + '\n' + event.fault.faultDetail)" showBusyCursor="true"> <adminservice:channelSet> <s:ChannelSet> <s:AMFChannel uri="http://localhost:8080/conferenceguide/messagebroker/amf"/> </s:ChannelSet> </adminservice:channelSet> </adminservice:AdminService>
And there you go. Special thanks to James Ward, whose screencasts really helped me get it right. Now the only thing that this plugin misses, beyond the 2 known limitations, is integration with Spring Security, but this is just a start.
Following up on my reflexion about what could software development look like a few years or decades from now, there is this big problem that has been bugging me for years now and that I have never found the time to really tackle: expressivity. In the same way as files appear to me as the biggest obstacle to collaboration, I think the main barrier in the way of expressivity is TEXT.
It’s hard to admit, but we’re still building software like cavemen. We don’t have spoken language, just a bunch of noises, we don’t conceptualize much but we do communicate with a few gestures and more importantly some colored drawings on cave walls. The way I see it, we are not much more advanced than that, but it’s normal, software is still relatively young as a discipline and although it has already changed our lives, we have to imagine that it’s just the beginning. And the good news is that we are headed in the right direction.
We started off with most elementary way of storing information and communicating with a machine: zeros and ones. Binary. It was too elementary, more like noises coming out of our mouths, so we started to group bits in octets corresponding to hardware instructions and characters. In fact, we added gestures to noises. Then we grouped instructions into statements and procedures, and we designed a way to translate those into the most elementary form of language that machines could understand. We started drawing on walls. But as procedures multiplied like crazy, we needed to conceptualize some more, talking about classes, objects, methods, properties, and so on. Spoken language was born. And with higher level concepts like services, components and multiple programming languages, we added written language. OK, the analogy is not that good, but you get my point: I’m convinced we’re still very early in the overall evolution of communication with machines, and although this evolution is somewhat slow and creates a lot of inertia, I believe that if we want computers to really expand our capabilities (note that I didn’t say “replace us”), we need to go further in abstraction levels.
So what’s next? Binary, assembly, procedural, object-oriented (yes, and functional, if you want), then what? Model-driven? I’ve tried that, it’s just replacing the constraints of text with the constraints of visual representations. It sure makes it easier to conceptualize, but at some point we’re still translating those visual models into text code, which we have to compile. The roundtrip is just too long. What about domain-specific languages? Well, I’m more into that right now. It looks like communicating is naturally based on languages, collections of concepts that relate with one another to describe what a software is and what it does. So focusing on making it easier to define new languages definitely goes in the right direction. That’s why it’s so linked with meta-programming: instead of statically defining layers upon layers of fixed concepts to describe systems with even higher level abstractions, let’s define the root concepts we will use to describe languages that will allow us to describe our systems. That’s why I’m so interested in Groovy at the moment for internal DSLs, although I prefer the more elegant idea of external DSLs and language workbenches, like Jetbrains MPS does.
All of this evolution makes me think of a video I saw recently, that tried to make String theory more accessible:
Let’s say binary is our dimension 0. Assembly is dimension 1: a line. Procedural programming is dimension 2: a plane. Object-Oriented Programming is then 3rd dimension: a volume. And it’s very hard for us to leave it, as it is our most natural way of seeing things. But that’s where I find this explanation of String theory particulary interesting (although not rigorous as some math geek friends of mine pointed out): there starts a cycle. Dimension 4 is a line again, formed by 2 different Object-Oriented Languages, like Java and C++ for example. Still there? Good! That’s where the fun starts: dimension 5 is a plane composed by all the parallel universes that are created by our own choices. Functional programming and OOP can be considered as forming such a plan. Now what if we could design a way to go directly from one of those paradigms to another one, to fold the plane in the 6th dimension: please welcome language-oriented (or meta-) programming! See the cycle? Now most of us are stuck in the 3rd dimension, and some of us are already experiencing the 6th dimension.
So there we are. Seventh dimension is the line joining the set of all possible timelines starting from our software big bang, which is the binary transistor, to another set of possible timelines, starting from another big bang. Quantum computing can be another option, but it’s a hardware one. What about software? Isn’t virtualization a way to forget about the physical hardware? And there we go 8th dimension: going from binary transistors to quantum computing is one line in the seventh dimension. Choosing to go to virtualization instead creates an branching line in the 8th dimension. Which means that if we want to create our ninth dimension, we need to fold the eighth in order to jump from quantum to virtual computing. And that’s where I locate what I call Culture-Oriented Programming. The third stage of the third 3-stage cycle. The final frontier? The next step? Hooooo… my head hurts.
But wait a second, I only talked about computing here. A virtual reality. What if dimension 10 was the line uniting computing with the real world in the purest possible way. Direct communication between human beings and computers. Who said “scary”?
PS: I didn’t intend this post to be so “theoretical”. I only thought with my keyboard and let my imagination go. But I’d love to know what you think about that crazy analogy? Do you think we are limited to 11 dimensions like in string theory?
PPS: That might be my geekiest post EVER!