If you want to check if one class inherits another without actually having instances of those classes, you may have read my article on Checking Class Inheritance. However, as the many comments quickly pointed out, the methods of checking this may have some flaws. There were also additional methods posted in the comments that should be added and tested. Today I’m adding them, testing them, and checking all of their validity to find the ultimate approach to check class inheritance.
Posts Tagged class
Compile Time Only
Mar 19
The const and final keywords only apply at compile time. Despite having written about const and final before, readers frequently ask me about these two keywords. Today’s article will answer the question and definitively show that these keywords only apply at compile time: not runtime. UPDATE: const is still just a variable as far as performance goes, but its protections do extend to runtime.
Serialize Anything
Nov 21
The ByteArray class, introduced in Flash Player 9, has a pair of very powerful functions alongside all the usual ones like writeInt. It actually allows you to read and write AS3 objects and provides an easy, fast, and compact way to serialize anything without writing any code. Today’s article explores shows you how to harness the power of these functions to improve your data serialization and deserialization.
I recently received a tip about a thread discussing an interesting problem: how to tell if one Class object represents a class that subclasses another Class object. If you had an instance of the class, you could simply use the is or instanceof keywords, but that won’t do here. Today’s article shows how to solve this tricky problem.
One of the very nice features of AS3 (and AS2 and JavaScript for that matter) is that you can dynamically access the fields of any object. This leads to much more dynamic code since you no longer need to know what field to access at compile time. As we’ve often seen with other dynamic features, this can come at a steep cost in terms of performance. Today we’ll see just how slow accessing fields this way is to get a good idea of just how much performance we give up when using this feature.
Dynamic Field Access
Mar 21
AS3 has an interesting feature that is sometimes used to great effect: dynamic classes. These classes can have fields added and removed to them and used like any other field. You can even make your own dynamic classes with the dynamic keyword. However, all of this fancy functionality comes at a steep performance cost. How steep? Read on to see just how steep.
Class Bootup Part 2
Jan 31
Today’s article follows up on an article I wrote way back in August of 2009 about the order of operations when you use a class. In the original article I showed the order of field initializers and constructors. Today I’m expanding on that to show three more chunks of code that are run. Can you guess what those chunks are?
Accessing Objects
Oct 18
There are three main ways to access the contents of objects in AS3: the dot (.) operator, the index ([]) operator, and the in operator. The first two are well known and functionally-equivalent because obj.property evaluates to the same value as obj["property"]. The in operator is different as I’ve described before: it returns a Boolean indicating whether or not the object has the given property. There are a lot of cases—error checking, for example—where we only care if an object has a property and not what that property is. So, can we improve performance by using the is operator rather than the index or dot operators? (UPDATE: hasOwnProperty results added)
The Size of Empty
Apr 20
I was reminded about the flash.sampler API by Grant Skinner’s recent post about it. While only available in the debug player, it can still tell us some valuable information about what goes on in the release player. Today I’m using the getSize function to find out how much memory overhead various classes impose, even when they are empty.
