You can check it out here: labs.jam3media.com

Lets look at some really really simple example of some semi-psuedo ActionScript that doesn’t use polymorphism:


function speak(animalType:String){
switch(animalType){
case "dog":
woof();
break;
case "cat":
meow();
break;
case "pig":
oink();
break;
}
}

trace( speak(“cat”))    //meow

This is pretty long and ugly just to get an animal to make noise.  Now, lets do this same thing using polymorphism:
function speak(animal:Animal){
animal.speak();
}
trace(speak(cat))  //meow


This is way shorter! So what did we do here? First off in the original example we passed the speak function a string id to an animal and then the switch decides what that animal does when it talks. In the second one, we simply passed an animal type to our speak function..and it just called its speak function.

Basically,  All three of the animals implement an animal interface. This means they share one or more methods in common.  To keep our animal metaphor going, all three animals speak, eat, poop.  But they all eat different things!  They say different things! However, if you had a real dog or cat and had trained it to your commands.. you would say “sit!” and expect it to sit. You wouldn’t explain to it how to sit. The cat or dog just knows it. With polymorphism its the same thing. You tell the cat to speak and it just does it. They all have the speak() method but each animal implements it differently.

Another use of polymorphimism would be different sections of a website. Each section could implement an a section interface with animateOut and AnimateIn calls but home section could animate in one way and the contact section another. The code calling the methods doesn’t care what they do as long as the object does something when its told to.  This in its heart is polymorphism.  At its simplest form its a way to achieve different results using the same code.  This means shorter, clearer code that can be easily modified. you don’t have to update some crazy switch statement evertime you add a new animal. You just make sure the new animal implements the interface and everything else will magically work.

Hopefully, you’ve learned something here and in your next project you’ll plan a little ahead and architect your project to better use polymorphism and to ultimately write cleaner/better code.

Screen shot of CircleClock in action

Its pretty simple.. The 4 circles represent different measurements of time.  The innermost circle is showing tenths of a second, the next seconds, then minutes and hours. Again, almost impossible to tell what time it is, but cool looking nonetheless.

The code for this is actually pretty simple. The hardest part was actually getting the time in a format that i could parse easily.   For this I had to checking the current time of my phone and then giving my Date object that time.

Date date = new Date();
Calendar cal = Calendar.getInstance();
date.setTime(System.currentTimeMillis());
cal.setTime(date);

Now that I have my calendar object up to date with the correct time i’m able to tell each of the clock “hands” what time they should display.

Hand milli;   
Hand seconds;
Hand minutes;
Hand hours;
milli.setValue(cal.get(Calendar.MILLISECOND)/100, 10);
seconds.setValue(cal.get(Calendar.SECOND), 60);
minutes.setValue(cal.get(Calendar.MINUTE), 60);
hours.setValue(cal.get(Calendar.HOUR_OF_DAY), 24);

The first value that gets passed into each Hand  is value while the second is the total number of either seconds in a minute, minutes in an hour or hours in a day. The clock hands just show what percentage of the total they are at. I’m pretty sure this isn’t the best way to do something like this but it works quite well.  This seemed to be the only way that i could easily parse the time into something manageable. There are other methods for generating nicely formatted strings but they aren’t good for extracting the values for  milliseconds, seconds or minutes.

You can download CircleClock for your Blackberry Storm here. Requires OS 5.0.  Actually…it might work on any phone, and while I used a 5.0 SDK I don’t know if I actually used anything that wouldn’t work on something using 4.0. I haven’t tested it on anything other than my storm 9530. In any case  use completely at your own risk even on the recommended hardware/software. Its probably full of bugs.

I’m planning on using this space to talk about the various projects i’m working on. Show new stuff that i’ve learned, post some projects… get my name out there.

I’ve recently begun working with Java and blackberry application development. Hope to show some of that off here too.