Using my objects as keys in a hash map

Question

I need the following type of code to work (ClDate is my own class):
            var testDic:Dictionary = new Dictionary();
            var key1:ClDate = new ClDate(10000);
            var key2:ClDate = new ClDate(20000);
            var key3:ClDate = new ClDate(30000);
            var key4:ClDate = new ClDate(40000);
            testDic[key1] = 1;
            testDic[key2] = 2;
            testDic[key3] = 3;
            testDic[key4] = 4;
            var key:ClDate = new ClDate(20000);
            var retNum:Number = testDic[key];
The current Dictionary or Array does not work since they do not enable passing a comparison function that will enable comparing my own objects. Is there any existing implementation that works?
-Sam.

Answer 1

Object (when acting as a map) uses toString() as a poor man's hashcode implementation, so you can get more-or-less the behavior you want by implementing the toString() method in your CIDate class and then storing the instances in an Object (rather than a Dictionary).
E.g., say your CIDate looks like this:
          public class CIDate {
            public var num:Number
            public function CIDate(num:Number) { this.num = num }
            public function toString():String { return num.toString(); }
You can use toString() as a comparison operator by keeping things in an Object instead of a Dictionary:
            var testDic:Object = {};
            var key1:ClDate = new ClDate(10000);
            var key2:ClDate = new ClDate(20000);
            var key3:ClDate = new ClDate(30000);
            var key4:ClDate = new ClDate(40000);
            testDic[key1] = 1;
            testDic[key2] = 2;
            testDic[key3] = 3;
            testDic[key4] = 4;
            var key:ClDate = new ClDate(20000);
            var retNum:Number = testDic[key];
Then retNum should be '2', as expected. This is sort of a hack, but it might work for what you're doing.