I know its bad in that in that it kind of stops me from exploring the potentials provided by other languages in full. Its like going to a Chinese restaurant and eating fried rice everytime because fried rice is the only dish that is close to what I’m used to eating daily.
There’s such variety in Chinese food, and yet if I go there and I eat fried-rice evertyime Its a sign I have a bit of a problem opening myself up to new things. And that’s a big problem.

The world has such diversity in every-aspect imaginable, ( with the exception of mob-justice and mob-mentality which seem to cross all cultural and geographical boundary as it seems), and not being able to appreciate the diversity and learn for it is a great pity.

Back to programming, not all constructs  found in languages are sole property of a  given language. They are  generally abstractions provided by languages to solve problems effectively and those abstractions can be applied in other languages even if they don’t provide such explicit constructs.

There was a time when I treated javascript like lepers, something to avoid at all cost, except when it was really unavoidable.
But then I had a change of perspective, at a philosophical level -dare I day. ‘If I avoid something to such length then I must be shit-scared of it for some reason’.
And by nature I hate to admit my fears for the fear of being tagged a wussy, a chicken.
Of course I can find things to justify my avoidance of javascript to others without admitting my fear, but how about myself?
What do I tell myself when I go to sleep??
And since I couldn’t find reasonable arguments to fool myself into good sleep because my rational self always counter-argued that ‘you  fear what you don’t understand’, and my arguments against javascript were just my lame attempt to hide my fears , I decided to deal with my fears for once and for good.

And since then I have been quite happy with my javascript experience.

Since I’m still a Java fan-boy, though I have a feeling that it won’t be for  too long, Scala! here I come,  I tried to find solution to variable scoping in javascript so that I have more control over objects I create and the API’s I expose. This has been a big issue due to the need for me to use at least 3-4 third-party libraries to get my job done for the current project I’m rewriting.
And the project has a massive javascript code-base.

Looking back at the code I did last year makes me cringe. There was no modularity and there was too much interdependency between components and objects.

(Hmm… component decoupling is entirely another topic for another sleepless night.)

And this time around I decided to do thing the right way – at least to my best knowledge.

After long hours prowling the internet, finally I managed to understand the trick to accomplish what I wanted.

So here’s an example of an object with everything pubic, the dumbest example.

var Person= function(name ,surname, sex, dob){

this.name=name;
this.surname=surname;
this.sex=sex;
this.dob=dob;

this.getFullName=function(){

return this.surname+","+this.name;
}

this.getAge=function(){

return (new Date().getYear() - this.dob.getYear()) ) ;// I'm being lazy here

}

}

// another a little less dumb-looking flavor with prototyping but dumb nonetheless
var Person= function(name ,surname, sex, dob){

this.name=name;
this.surname=surname;
this.sex=sex;
this.dob=dob;
}

Person.prototype.getFullName=function(){
return this.surname+","+this.name;
}
Person.prototype.getAge=function(){
return (new Date().getYear() - this.dob.getYear()) ) ;
}

All the properties in of the object are accessible to any function/code that instantiates Person object. And getFullName() is nothing more but a handy method for getting both name and surname.
And the calling code can access dob and compute age by itself.
So everything is accessible.

var person = new Person('inny', 'minny', 'yes please', new Date(1901, 0, 1) );

var fullname= person.surname+","+person.name;

var age=  (new Date().getYear() - person .dob.getYear()) ) ;

Of course one can argue that we can differentiate the difference between private and public by using underscore for private properties such as _dob ( as a lot of people insist on doing).

But who are we fooling? That’s just a convention we use, and if you work in a large team there’s no guarantee that someone else will not get smart and start mutating the underscored variable and shit might hit the fan depending on how critical the property is.

Instead of developing ad-hoc convention I believe its more ideal to use the best of what a language provides without having to define our own rule which can be broken by anyone who cares to break it. Sometimes I don’t trust myself,let alone trust others.

So if we need to hide the DOB for privacy reason and only expose the age,  and we need to hide the individual name and surname for some reason, here’s how its done:

var Person= function(name ,surname, sex, dob){

this.sex=sex;

this.getFullName=function(){

return surname+","+name;
}

this.getAge=function(){

return  (new Date().getYear() - .dob.getYear()) ) ;

}
}
Person.prototype.getGender=function(){
var sex=this.sex,tolowerCase();
if( sex=='male' || sex=='m' )
return 'male';
else if( sex=='female' || sex=='f' )
rerturn 'female';
else
return 'god knows';

}

Person.prototype.getSpecies=function(){

return 'mammal';
}

In the above example, any instantiating code has only access to getFullName() , getAge() functions and ’sex’ variable of person object.
But we allow ’sex’ variable to be declared in two forms, long and short. And we return ’sex’ in  long format with the help o getGender() helper function.

The above example can be broken down as following;

All variables except sex are private as they are constructor-scoped.
getFullName() and getAge() are privilaged function that have access to private variables name, surname and sex and thus are privileged/protected functions.

getGender() is a public function that has access to public variable sex.
the new getSpecies() is a public function that returns a value that’s entirely in its own scope.

So, there we have it, private, privileged and public access in javascript.

If we want to use module pattern the above can be modified to:

var Person= function(name ,surname, sex, dob){

this.sex=sex;
return{

getFullName:function(){

return surname+","+name;
},

getAge:function(){

return  (new Date().getYear() - this.dob.getYear()) ) ;

},
getSpecies:function(){

return 'mammal';
}

}
}

An example of creating static object with private and public scope:

var Human = function() {

var species = "mammal";

return {

alert: function(){alert(species);}

};
}();

Human.alert();//displays 'mammal'

Here the variable species is private.
The function gets executed immediately due to () at the end of the function definition and will return a public static method alert()

That sums up variable scopes in javascript.

I jsut used the  similar principle I used with php, but the problem is importing all files in a package isn’t possible in javascript because  javascript cannot read files form disk let alone iterate through a folder and read file content.
For that there was nothing I could do except use some server-side help.

here’s the js file code with  function for importing js file and js files contained in a package(folder).

//create namespace to aviod any present/ future  variable/object/funciton conflicts

if (typeof Anzaan == "undefined" || !Anzaan) {

Anzaan = {};
}

// array to hold all imported files so as not to import them twice
Anzaan.imports = [];

//server side URL for loading whole package content
Anzaan.packageLoaderURL='/Framework/packageLoader/';

//set the base folder for importing files
Anzaan.importBase='js/';

/**
* import a class using the java naming syntax for a class name.
*@param module the module to import
*@param  config object literal with two properties-
* config.packageLoaderURL - the server url for loading all files in a folder/package as a stream
* config.importBase - the base path for importing files
* use config only if necessary otherwise just modify Anzaan.packageLoaderURL and Anzaan.importBase
* of course you can use a different namespace or just use no namespace
*/
function Import(module, config) { //com.anzaan.framework.*

if(config){
if(config.packageLoaderURL)
Anzaan.packageLoaderURL=config.packageLoaderURL;

if(config.importBase)
Anzaan.importBase=config.importBase;
}

// if this import has already happened, don't bother,
if (Anzaan.imports[module] )
return ;

var head= document.getElementsByTagName('head')[0];
var script= document.createElement('script');
script.type= 'text/javascript';

var src='';
var folders=module.split(".");
for(var i=0;i<folders.length;i++){

if(folders[i].indexOf('*') < 0)
src+=folders[i]+"/";
}
src=src.substring(0,src.length-1);//remove the last slash

if (module.indexOf('*') < 0) { //if not package import
src=Anzaan.importBase+src+".js";
script.src=src;

} else {
script.src=Anzaan.packageLoaderURL+"?package="+Anzaan.importBase+src;
}

head.appendChild(script);
Anzaan.imports[module] = module;
}

The config parameter is optional. It shouldn’t really be used unless you want to load files from locations other tahn the default location of your application and want to use other URL for loading script files.

Just modify the global variables Anzaan.packageLoaderURL and Anzaan.importBase to set the base path and the serverside URL for loading scripts in folder.
And of course rename Anzaan to something more meaningful for you.

Now on the server side here’s a simple php script that services the script file requests.
It loads contents from js flies that reside in folder specified by ‘package’  variable.

packageLoader.php
————————————————

<?php

$folder=$_GET["package"]; // get the package name

$dir = opendir($folder); //open directory

while (($file = readdir($dir)) !== false) {
if (strrpos($file, '.js')) {

echo file_get_contents($folder.'/'.$file); //printout the content of file

}
}

?>

and here’s a Java Servlet for doing the same thing:

JSPackageLoaderServlet.java

public class JSPackageLoaderServlet extends HttpServlet {

@Override
public void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {

response.setContentType("text/plain");
ServletOutputStream out = response.getOutputStream();

String packagePath = request.getParameter("package");

StringBuilder sb = new StringBuilder();

File myDir = new File(getServletContext().getRealPath(packagePath));
if (myDir.exists() && myDir.isDirectory()) {
File[] files = myDir.listFiles();
for (int y = 0; y < files.length; y++) {

String line = "";
BufferedReader in = new BufferedReader(new FileReader(files[y]));

while ((line = in.readLine()) != null) {
sb.append(line);

}

}

}
out.print(sb.toString());
}
}

Here’s the usage:

Import('anzaan.event.EvenHandler');

Like all good customers, their patience on the two months timeframe i had given them to get Fiji’s map up and running ran out before the deadline  and last week I promised them I’ll show them at least something within a week.  And of course I had no clue how I was going to keep that promise.

I tried my hand on all sorts of things, I tried to configure and run our own map server to spit our tiles for Fiji,  I tried overlaying Fiji’s map data (which the client provided as shapefiles and it only covered a part of Fiji) on google map, I used good-old Firebug to debug OpenGTS’s
tracking website to see how they did their tracking using Open Street Map.

I had two plans.
Plan A: whatever it takes get the fiji’s map to load inside google map so I can use the existing javascript codebase that relies on google’s api.
Plan B: Use OSM for Fiji and google for rest,  and rewrite javascript code and use OpenLayer  javascript  library as the main library to allow users to switch ebtween providers easily.

Since Plan A is less painful, I tried to find ways to accomplish it. And Plan A  indeed turned out to be extremely painless if there’s such a thing.

I won’t go detail out all the things that failed, but I’ll definitely detail out what worked.

So, to all my fellow colleagues, cursing themselves in their little office cubicle, tearing their hair our trying to integrate OSM in google map,
here’s the solution:

We’ll create a new map type and point google to OSM ’s tile provider to get map tiles from OSM instead of fetching them from google’s servers.

Firstly, We’ll create a new GTileLayer for osm.

var osmTileLayer= new GTileLayer(new GCopyrightCollection(”"),1,17);
osmLayer.myLayers=’osm’;
osmLayer.myFormat=’image/jpeg’;

This is where we define a custom function for fetchng tiles from OSM map server.
This function will be user by google to fetch tiles from OSM everytime there’s request for tiles.

osmLayer.getTileUrl=function(a,b,c) {

return ‘http://c.tile.openstreetmap.org/’+b+’/'+a.x+’/'+a.y+’.png’;

}

Then we create a map type and add it to our good old google map.

var osmLayer=[osmTileLayer];
var OSMMap = new GMapType(osmLayer, G_SATELLITE_MAP.getProjection(), “OSM”, G_SATELLITE_MAP);
map.addMapType(OSMMap );

And that’s it !!
That’s all it takes to add Open Street Map as a new map type in google map.

here’s the complete code:
————————————————

var osmTileLayer= new GTileLayer(new GCopyrightCollection(”"),1,17);
osmLayer.myLayers=’osm’;
osmLayer.myFormat=’image/jpeg’;
osmLayer.getTileUrl=function(a,b,c) {

return ‘http://c.tile.openstreetmap.org/’+b+’/'+a.x+’/'+a.y+’.png’;

}

var osmLayer=[osmTileLayer];
var OSMMap = new GMapType(osmLayer, G_SATELLITE_MAP.getProjection(), “OSM”, G_SATELLITE_MAP);
map.addMapType(OSMMap );

—————————————————–

and here’s the final result: