Useful ObjectScript Functions

Useful ObjectScript Functions

ObjectScript provides the following functions for use with object classes:

• $CLASSMETHOD enables you to run a class method, given as class name and method name. For example:

  TESTNAMESPACE>set class="Sample.Person"
   
  TESTNAMESPACE>set obj=$CLASSMETHOD(class,"%OpenId",1)
   
  TESTNAMESPACE>w obj.Name
  Van De Griek,Charlotte M.
  

  

  This function is useful when you need to write generic code that executes a class method, but the class name (or even the method name) is not known in advance. For example:

   //read name of class from imported document
   Set class=$list(headerElement,1) 
   // create header object
   Set headerObj=$classmethod(class,"%New")

  

  The other functions are useful in similar scenarios.

• $METHOD enables you to run an instance method, given an instance and a method name. For example:

  TESTNAMESPACE>set obj=##class(Sample.Person).%OpenId(1)
   
  TESTNAMESPACE>do $METHOD(obj,"PrintPerson")
   
  Name: Van De Griek,Charlotte M.
  

  

• $PROPERTY gets or sets the value of the given property for the given instance. For example:

  TESTNAMESPACE>set obj=##class(Sample.Person).%OpenId(2)
   
  TESTNAMESPACE>write $property(obj,"Name")
  Edison,Patrick J.
  

  

• $PARAMETER gets the value of the given class parameter, given an instance. For example:

  TESTNAMESPACE>set obj=##class(Sample.Person).%OpenId(2)
   
  TESTNAMESPACE>write $parameter(obj,"EXTENTQUERYSPEC")
  Name,SSN,Home.City,Home.State
  

  

• $CLASSNAME returns the class name for a given instance. For example:

  TESTNAMESPACE>set obj=##class(Sample.Person).%OpenId(1)
   
  TESTNAMESPACE>write $CLASSNAME(obj)
  Sample.Person
  

  

  With no argument, this function returns the class name of the current context. This can be useful in instance methods.