Map by Class in Dart -

Dart porting some Java-code and it makes heavy use of these types of maps:

 
  
 
  Maps & lt; Classroom & lt;? Some classes & gt; Spreads, some other class & gt; Map = new hashmap & lt; & Gt; ();   
 At the moment it seems impossible in dart. I know that the first level types are proposed to be introduced: which will apply  
  class type {@native String toString ());   
 So until this proposal is implemented I have created the following class:  
  class type {last string classname; Const type (this.classname); String descriptor () = & gt; class name; }   
 And get the simple sections of the sections I need it  
  type type Please);   
 In this way I can use my  type  as I would use the actual  type  and switch to later Just remove my solution.  
 My question: Is there something wrong with doing this mapping (which I am not seeing) or by the way I take it as appropriate to the actual  type            
 -Dart printing-override ">  Var map = new map & lt; type, someOtherClass & gt; (); // either map [SomeOtherClass] = new some other class (); // or var example = new SomeOtherClass (); map [instance.runtimeType ] = Example;    
 
 
  update : This build is not currently capable of dart  
  map & lt; class & lt;? Some class & gt; spreads , Some other class & gt;   
 You have to wait for  .type / .class  so that it can get a beautiful solution (many of us Dartisans are hoping that it will soon come later), though for the simple case,  
  map & lt;? Some classes, some other classes & gt;   
 You can do just that  
  Maps & lt; SomeClass, SomeOtherClass & gt; A map;   
 Any square spread across  SomeClass  as a dart is going to be  SomeClass  for example if you use the following code Run in check mode:  
  main () {map & lt; Test, string & gt; Mapp = new hashmap   
 Then you will get an error:  
  type 'Notatest' type is not a sub type 'key 'Test' of '