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Archive for the ‘Groovy Development’ Category

Introducing – GuildWars2 Commander Overlay

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Hi folks,

as the creator of I’m using my blog to promote this little goody 🙂

What is it? It’s a windows 7+ application/overlay above GuildWars2 showing timers and team movements for a game mode called World vs. World. Here three home worlds/servers combat each other player vs. player for a week by killing other raids or conquering castles, towers and supply camps. now enriches this in multiple ways:

– Cooperative team play by seeing where other teams are heading to. You may have a coordinater in Teamspeak ordering teams to go here and there
– Know beforehand if the camp you’re heading to with your raid still has a timer
– Predict enemy movements be looking at the map overview
– Allows for visibile scouts too so a leader can see which objectives are protected by manpower
– Getting infos about who has claimed an objective and how long it is held

The cool thing about this is the work-out-of-the box character. You as GW2 player just fire up the game and join a WvW map. The Client (after you logged in) can automaticly pick up the map and your character and will (not yet implemented) place you into the correct team based on the leaders teamname and your login. There is nearly zero interaction needed but the team leader will see the new player as a team member.

The client is free and our complete server infrastructure that is able to support thousands of players at the same time costs (incl. Domain) not even 10$ a month. On the technology side we are using many technologies like ZeroMQ, Google AppEngine with Gaelyk and Protocolbuffers. We’ve overcome OS and program language boundaries and created a secure communication over an unsecure tcp socket. There were many challanges and I hope to have the time to blog details here about some of them.

It took me and a friend (plus some recently joined supporters) a year now from idea to the current closed Beta Version and I hope a public Beta for my whole home world “Elonareach” will be ready within four weeks.

Stay tuned,

Written by ghads

June 23, 2014 at 3:53 pm

HTML5 <time> microformat with Grails (UTC dates…)

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As I mentioned last post I’m doing a little pet project with Grails, HTML5 and MongoDB. Now I wanted to include the rendering of dates in StackOverflow style, something like: 5 minutes ago, about an hour ago and such. As HTML5 defines a <time> microformat I naturally wanted to use this one today and also found a nice jQuery plugin to convert times into the format I like: timeago. This one also includes support for the <time> tag by default.

But there’s a catch (as always…). The <time> tag and the plugin depend on ISO8601 UTC dates, which MongoDB stores nicely. But by getting data from MongoDB, you have your java.util.Date class and trouble starts, as there is no default way of formatting and recalculating dates to UTC with one call. Else I could have used the Grails included formatDate tag.

So I first searched for an easy way to format a Date instance to ISO8601 UTC format. Luckily I found the following post that shows how to set UTC for a formatter and the right format string for ISO8601. As this is a two line call and I didn’t want to make a Utils-Class for representation only to call it from the controller and having a String for rendering instead of a Date. And I didn’t want to include the formatter code on every page, I came up with a Grails Filter solution.

By including this class in grails-app/conf:

class MyFilters {
	def filters = {
		addUtils(controller:'*', action:'*') {
			after = {
				// add formatter for UTC dates in ISO8601 format
				SimpleDateFormat ISO8601UTC = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")
				params["_UTC"] = ISO8601UTC

I have a new formatter instance inside the params ready to use for formating dates to UTC in the correct way for the tag:

<time class="timeago" datetime="${params._UTC.format(created)}">${created}</time>

I used an underscore to seperate the utils from regular paramaters used to render the site. For now I don’t care about a new instance for every call, but if you care, just make the formatter static and reduce the scope of the addUtils Filter to only the pages that need it.


Written by ghads

January 26, 2011 at 3:10 pm

Grails + HTML5 = Works

with 6 comments

Today while building a project to test MongoDB integration with Grails, I was curious whether Grails can emit HTML5. So I just tried to apply to great HTML5 Boilerplate ( template and it worked out wonderful. I just changed the default main.gsp, main.css and application.js and added some more files…

Of course some things need adaption:

– Using jQuery 1.4.4 instead of 1.4.2
– All hardcoded path replaced with ${resource(dir:’images’,file:’favicon.ico’)} for example
– Javascript libs can be embedded with <g:javascript library=”…” /> instead of a hard coded path, when you place your lib file into the web-app/js folder
– For JQuery Fallback loading the src can be exchanged with ${resource(dir:’js’,file:’jQuery-1.4.4.js’)} to avoid hard path coding
– Because of the templating/layout nature of Grails view, JavaScript loading of jQuery and the additional plugins.js and application.js (also via <g:javascript …>) cannot be pushed to the very end of the page, but must be loaded before any part of a page is been decoreted by the template (except for belatedpng)
– I reused the default spinner div, but cleared the default grails code in application.js and introduced two simple functions for showing and hiding the spinner
– For flexible layout I used the following construct plus two additional GSPs header.gsp and footer.gsp

<div id="container">
  <g:applyLayout name="header" >
   <content tag="header">
    <g:pageProperty name="page.header" />
 <div id="main">
  <g:layoutBody />
  <g:applyLayout name="footer">
   <content tag="footer">
    <g:pageProperty name="page.footer" />

This enables the header.gsp and footer.gsp to include portions of the GSP page to show while being modular. The header/footer.gsp looks like:

<%@ page contentType="text/html;charset=UTF-8" %>
<b>Footer begin...</b>
<g:pageProperty name="page.footer" />
<b>Footer end...</b>

While a GSP page may looks like:

<%@ page contentType="text/html;charset=UTF-8" %>
  <title>my title</title>
  <meta name="layout" content="main">
  <content tag="header">
   … draw the header here…
  <h1>Hello ${name}!</h1>
  <content tag="footer">
   … draw the footer here…

This allows for dynamic customizing of header/footer portions per page if desired, e.g. to render a status per page, which has its position and styling defined via the layout.

The rendered result of this looks like:

Header begin… … draw the header here… Header end…
Hello World!
Footer begin… … draw the footer here… Footer end…

The HTML5 Validator only complaints about the chrome frame but validates my rendered test page sourcecode without any moaning.

For CSS3, the integration was a nobrainer, I just added everything to main.css, removed all grails styles and used a @import url(styles.css); for a clear seperation of predefined and own styles at styles.css. The W3C Validator for CSS3 doen’t really like the main.css file, but as it comes directly from the boilerplate template I don’t really care. I can now start writing my pet project with HTML5 and CSS3 and can be sure to have maximum compatibility with yesterdays, todays and tomorrows browser and will update my code when a new version of the fantastic boilerplate template comes out.

Oh, for your own integration before going productive don’t forget to add expires to external resources, minify .css and .js files to one and enably GZIP transfer at your server. That should be all for a snappy cool HTML5/CSS3 site done with grails.

Have fun and greetings,

Written by ghads

January 21, 2011 at 9:43 am

Short update

with one comment

Hi @all and a happy new year 🙂

Yeah, I know, it’s little bit late already, but I simply had no time to blog earlier. Too much to do with testing out Win7 and hacking java and vbscript…

Anyway, here are some new cool findings to check out: – Grid-based computing of fractal mantras as screensaver

Consider GlassFish ESB v2 for SOA Tooling ( for a good tutorial about GlassFish, NetBeans, ESB and BPEL – Where you can learn about many aspects of Java developing technologies (with passion 🙂 – Get quick and easy groovelets to work at your favourite (application) server and why those groovy servlets rock – A generic proxy approch to the builder pattern – A portable ISO mounting/creating solution for Windows

So long and many greetz,

Written by ghads

February 2, 2009 at 12:38 pm

Bringing together .NET and Java

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I just researched some bridging technologies for calling Win DLL/Com objects from Java. I stumpled upon those two very usefull sites:

The first one shows how to write a COM DLL with VisualBasic, using other Com-Objects and accessing this new DLL from within Groovy and/or Java. This is something for making my Optimus Mini Three really usable from groovy/java I hope. The second one provides native functions via APIs to Java for creating IE, floating windows and retrieving system informations. Bringing this all together into an usefull application I will try 🙂

Greetz, GHad

Written by ghads

November 18, 2008 at 1:50 pm

Grails resources

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Hello again 🙂

This time I found a nice blog entry about Grails and an overview of must-reads and resources for developing your first grails website:

Looks worthy for a closer investigation of grails. Well, I wanted to develop my own grails site as a little private side project since summer, but I still have no time. I first need to get my infrastructure right, as my 2 1/2 year old notebook is getting buggy and slow and needs a replacemt and that needs money, which I don’t have (not even banks have money nower days…). Maybe next three month I’ll get new hardware and energy for my side projects. At least I hope so.

Greetz, GHad

Written by ghads

October 13, 2008 at 9:32 am

Writing DSLs with groovy

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Here’s a good presentation about DSL, groovy and things to consider. Enjoy!

Written by ghads

September 19, 2008 at 8:13 am

Posted in Groovy Development

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