In terms of configuration. Grails has no XML and the only properties files are i18n messages. Almost everything else is Groovy. I am familiar with 'convention over configuration' but I didn't know the configuration was so fluid and dynamic.
Many of the language features of Groovy become perfectly obvious in the context of Grails. The big one for me was named parameters. As a Groovy language feature. I was neutral on it; in the DSL setting of a web application the feature is vital. Similarly for closures and other constructions.
Also the MOP (Meta-Object Protocol) becomes extremely important. However it is so sublime that it is hard to "see". That is the Groovy code looks so lucid that it is easy to gloss over the machinations behind the scenes.
The MomentIn Grails we created a test application and created a domain class. Subsequently we created an MVC controller for our app. At this point we had a barebones app that could be launched and viewed. Cool beans. However the turning point for me was that Jeff said we could generate a controller: that is. Grails would generate the full code and then we could tweak it. Without a hint of irony or coyness he warned us that it would generate a lot of source-code. Being from the Java world. I braced myself for the output. Surely it would be verbose impenetrable and a rats nest in terms of formatting. Surprise: the generated Groovy was gorgeous. Due to the brevity and style of the language the generated code was 2 screens long -- without doc. And I was able to grok it and start tweaking it immediately. At first. I just started changing some code. But then I realized that I was working with generated code. That was the profound moment. I understood. Below. I've provided the generated code for a Gambler controller (think of a casino app) on my local machine. Give it a glance.... As a hint the controller contains several methods which are actions (in MVC parlance) on either a target Gambler object or a list of Gambler objects. Note that I'm not asking if you can understand it cold. I'm asking "do you think you could understand it if warm?". Remember.. this is generated. Personally. I think it is stunning. Final Score: Grails 1 My Old Biases 0. Check out.
class GamblerController { def index = { redirect(action:list,params:params) } // the delete save and update actions only accept POST requests def allowedMethods = [delete:'POST' save:'POST' update:'POST'] def list = { if(!params max) params max = 10 [ gamblerList: Gambler list( params ) ] } def show = { [ gambler : Gambler get( params id ) ] } def delete = { def gambler = Gambler get( params id ) if(gambler) { gambler delete() flash message = "Gambler ${params id} deleted" redirect(action:list) } else { flash message = "Gambler not found with id ${params id}" redirect(action:list) } } def edit = { def gambler = Gambler get( params id ) if(!gambler) { flash message = "Gambler not found with id ${params id}" redirect(action:list) } else { return [ gambler : gambler ] } } def update = { def gambler = Gambler get( params id ) if(gambler) { gambler properties = params if(!gambler hasErrors() && gambler save()) { flash message = "Gambler ${params id} updated" redirect(action:show,id:gambler id) } else { render(view:'edit',model:[gambler:gambler]) } } else { flash message = "Gambler not found with id ${params id}" redirect(action:edit,id:params id) } } def create = { def gambler = new Gambler() gambler properties = params return ['gambler':gambler] } def save = { def gambler = new Gambler(params) if(!gambler hasErrors() && gambler save()) { flash message = "Gambler ${gambler id} created" redirect(action:show,id:gambler id) } else { render(view:'create',model:[gambler:gambler]) } }}
As described in the composing software has much in common with composing music: both require talent and skill and both have a spectrum from apprentice to virtuoso. At times when composing software there is the palpable sense of beauty -- the comp sci equivalent of hearing the chorus of. That feeling is
I am a computer scientist part-time philosopher and part-time cyber-scriber. I live in St Louis. MO. USA and currently work on an agile dev team. I currently "think" in Java though I have torrid affairs with various scripting languages on occasion. I am not a musical composer but play guitar and am learning piano (on/off). I'm fairly literate with musical theory structures etc. That said my main hobby these days is triathlon. Alma Maters: and
All posts are solely mine and do not represent the views of my employer. Nor do they represent the views of Apple. Google. Sun or Microsoft (since I have no affiliation with these companies that probably isn't surprising). All photos of people with stickers are taken with permission with a full explanation for their use.
Forex Groups - Tips on Trading
Related article:
http://codetojoy.blogspot.com/2007/11/my-grails-moment.html
comments | Add comment | Report as Spam
|
