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Thread: Casting an Object value in the LHS
Casting an Object value in the LHS
country flaguser name
United States		 2008-04-28 11:38:52 

  


  

    Suppose I have a 
"Measurement" class, with a getName() method that returns a String 
and ;with a getValue() method that returns an Object.  Sometimes the 
Object is a String, sometimes a Integer, sometimes a Double.  I know that a "Foo" 
Measurement must be an integer, so I could cast (or otherwise coerce) into 
a form that can be compared with a constant integer (or other 
"Foo" Measurement).


 



How do I handle this 
type of value in the LHS of the rule?


 



when


 &nbsp;  $m : Measurement(name == "Foo", value < 10)


then


 &nbsp;  System.out.println("It's less than ten!");


end


 



I'd also like to be 
able to test for the Objects type (instanceof). I'm using java as my dialect, if 
that makes a difference. &nbsp; For other reasons I'd like to avoid having 
to either subclass Measurement or add type-specific value 
accessors.


 



-Russ

  

  
  
   
     
    

  

    Re:  Casting an Object value in the LHS
  


  

     user name

     2008-04-29 04:16:24
  


  

    

  


  

    You can use inline eval

&nbsp; &nbsp; $m : Measurement(
name == "Foo&quot;, 

eval(value instanceof Number),
value < 10)

2008/4/28  < rrogersus.imshealth.com">rrogersus.imshealth.com>:










Suppose I have a 
"Measurement&quot; class, with a getName()&nbsp;method that returns a String 
and ;with a getValue() method that returns an Object.&nbsp; Sometimes the 
Object is a String, sometimes a Integer, sometimes a Double.&nbsp; I know that a "Foo&quot; 
Measurement must be an integer, so I could cast (or otherwise coerce) into 
a form that can be compared with a constant integer (or other 
"Foo"&nbsp;Measurement).


 



How do I handle this 
type of value in the LHS of the rule?


 



when


 &nbsp;  $m : Measurement(name == "Foo&quot;, value < 10)


then


 &nbsp;  System.out.println(&quot;It's less than ten!");


end


 



I'd also like to be 
able to test for the Objects type (instanceof). I'm using java as my dialect, if 
that makes a difference. &nbsp; For other reasons I'd like to avoid having 
to either subclass Measurement or add type-specific value 
accessors.


 



-Russ



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