Ambient-Oriented Programming

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at:tutorial:symbiosis [2007/07/04 22:46] – jdedeckerat:tutorial:symbiosis [2007/07/05 09:36] – jdedecker
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 In Java methods can be overloaded based on the number of arguments and the types of the arguments.  Invoking an overloaded method from within AmbientTalk requires special consideration. In Java methods can be overloaded based on the number of arguments and the types of the arguments.  Invoking an overloaded method from within AmbientTalk requires special consideration.
 If the Java method is overloaded based on arity (i.e. each overloaded method takes a different number of arguments), the number of arguments in the AmbientTalk invocation can be used to identify a unique Java method. Hence, overloading based on arity does not require special attention. If the Java method is overloaded based solely on argument types, the interpreter may derive that the actual arguments can only be converted from AmbientTalk to the appropriate Java types for one of the matching overloaded signatures. Again, if only one match remains, the unique match is invoked. In the remaining case in which the actual AmbientTalk arguments satisfy more than one overloaded method signature, the symbiotic invocation fails. It is then the AmbientTalk programmer's responsibility to provide explicit type information in the method invocation. If the Java method is overloaded based on arity (i.e. each overloaded method takes a different number of arguments), the number of arguments in the AmbientTalk invocation can be used to identify a unique Java method. Hence, overloading based on arity does not require special attention. If the Java method is overloaded based solely on argument types, the interpreter may derive that the actual arguments can only be converted from AmbientTalk to the appropriate Java types for one of the matching overloaded signatures. Again, if only one match remains, the unique match is invoked. In the remaining case in which the actual AmbientTalk arguments satisfy more than one overloaded method signature, the symbiotic invocation fails. It is then the AmbientTalk programmer's responsibility to provide explicit type information in the method invocation.
 +
 +Selection of the correct overloaded method is done using the **cast** method.  In the example below the expression **aVector.remove** returns a closure for the Java method **remove**.  This closure understands the **cast** method which takes a variable argument list.  The arguments supplied to this method are the types of the method that needs to be selected.  In the example below the method **remove**, which is overloaded with the primitive type **int** and the type **Object**, are first selected and then invoked with the argument **0** and the argument **3**.  In the former case the first element in the list will be removed.  In the latter case the object **3** is removed from the vector.
  
 <code> <code>
->aVector.remove.cast(jlobby.java.lang.Integer)(1)+>def remove := aVector.remove 
 +>><java closure:remove> 
 +>remove.cast(jlobby.java.lang.Integer.TYPE)(0)
 >> >>
->aVector.remove.cast(jlobby.java.lang.Object)(3)+>aVector 
 +>> 
 +>remove.cast(jlobby.java.lang.Object)(3)
 >>true >>true
 +>aVector
 +>>
 </code> </code>
- 
-Selection of the correct overloaded method is done using the //cast// method. 
  
 ===== Accessing AmbientTalk from within Java ===== ===== Accessing AmbientTalk from within Java =====
at/tutorial/symbiosis.txt · Last modified: 2013/05/17 20:25 by tvcutsem