How to test if an object is a vector? - actionscript-3

Question

I want to test if an object is a vector, any vector, not only a vector of a single type.
I ran a test:
var v:Vector.<int> = new Vector.<int>();
v.push(3);
v.push(1);
v.push(2);
trace(v is Array); // false
trace(v is Vector); // false
trace(v is Vector.<int>); // true
trace(v is Vector.<*>); // false
It seems that the only thing that returns true is the one which specifies the vector type, but I want to test it for ANY type.
I will need a very efficient method to compare, because getQualifiedClassName is too slow.
My current approach is:
private static function isVector(obj:Object):Boolean {
return (getQualifiedClassName(obj).indexOf('__AS3__.vec::Vector') == 0);
}
But it is 2x slower than the is operator.
I need speed because it's for a object serialization class, and it needs to be very fast.

Answer 1

The problem is that Vector.<*> is a different class than that used for <Number>, <int>, or <uint>. The numeric primitives have special classes for better efficiency. String and Boolean are also primitives, but unlike the numeric primitives they are detected by <*>. As a result, you need only test for the generic Vector and the 3 numeric types.
This solution is over 2 times as fast as getQualifiedClassName in the worst case where the object is either not a Vector, or is a Vector.<uint>, and 5 times faster if the object is a non-primitive base type Vector, like Vector.<Object>:
return (obj is Vector.<*>
|| obj is Vector.<Number>
|| obj is Vector.<int>
|| obj is Vector.<uint>);
Here's a simplistic test:
var moo:Vector.<uint> = new Vector.<uint>();
var timer:Timer = new Timer();
var b:Boolean;
timer.startTimer();
for (var i:int = 0; i < 1000000; i++)
{
b = (moo is Vector.<*>
|| moo is Vector.<Number>
|| moo is Vector.<int>
|| moo is Vector.<uint>);
}
logger.info(" is timer: " + timer.endTimer());
timer.startTimer();
for (i = 0; i < 1000000; i++)
{
b = (flash.utils.getQualifiedClassName(moo).indexOf('__AS3__.vec::Vector') == 0);
}
logger.info("gqcn timer: " + timer.endTimer());
[LOG] com.tcg.test: is timer: 320
[LOG] com.tcg.test: gqcn timer: 756
Change moo to Vector.<Object>:
[LOG] com.tcg.test: is timer: 158
[LOG] com.tcg.test: gqcn timer: 743

Answer 2

Other methods are way too inefficient, so I'm still using my approach:
private static function isVector(obj:Object):Boolean {
return (getQualifiedClassName(obj).indexOf('__AS3__.vec::Vector') == 0);
}

Answer 3

trace(new Array().fixed);//undefined
trace(new Object().fixed);//undefined
trace(new Vector.<Sprite>().fixed);//false
trace(new Vector.<*>().fixed);// false

Answer 4

If you need serialization for any kind of object, you have to iterate over all possible types anyway, so you could use a sequential approach to find your vector type:
v is ... (simple data types)
v is ... (object types that are not collections)
v is Array
v is XMLList
v is ... (all other collection types you can think of)
if none of the above is true, it must be a vector
serialize objects in the vector. If you have more than one type, it's Vector.<*>, otherwise set the vector type according to the object type of the content items.

Answer 5

Use
(obj as Vector.<*>) is Vector.<*>

Answer 6

/// Return Class of any Target
static public function getClass( Target:* ):Class
{
return getDefinitionByName ( getQualifiedClassName( Target ) ) as Class ;
}
/// Check if object is type of Vector.< * >
static public function isVector( any:* ):Boolean
{
return String( getClass( any ) ).indexOf( "[class Vector.<" ) > -1;
}
/// Get Vector < Class >
static public function getVectorType( vector:* ):Class
{
var c:String = String( getClass( vector ) );
var s:int = c.indexOf( '<' ) + 1;
var e:int = c.indexOf( '>' );
return getDefinitionByName( c.substring( s, e ) ) as Class;
}

Answer 7

private function getIsVector(obj:Object):Boolean
{
return String(obj.constructor).indexOf('[class Vector.<*>]') == 0;
}