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--- at:tutorial:symbiosis [2007/06/19 10:26] – jdedecker
+++ at:tutorial:symbiosis [2007/06/19 10:55] – jdedecker
@@ Line 10: / Line 10: @@
 ===== Symbiosis Architecture =====
+AmbientTalk has been implemented in Java. Because of this, Java plays two roles: it is both a symbiont language and the implementation language of AmbientTalk (and hence of the linguistic symbiosis itself). Figure \ref{fig:wrappers} illustrates the different objects that play a part in the AmbientTalk/Java symbiosis, according to the implementation model of Inter-language reflection. AmbientTalk objects are physically implemented as Java objects. This is illustrated by means of the ``represents'' relationship. To enable symbiosis, additional objects are required which denote the //appearance// of objects from one language in the other language. At the implementation level, such appearances are implemented as //wrapper// objects, which wrap an object from a different language and which perform the protocol mapping which translates between the semantics of the symbiont languages.
+{{:at:tutorial:wrapper-architecture.png?450|Symbiotic representation of AmbientTalk and Java Objects}}
 ===== Accessing Java classes =====
@@ Line 45: / Line 48: @@
 </code>
+The AmbientTalk/Java symbiosis treats message sends from AmbientTalk to Java as follows: if a message is sent to a class wrapper, only static fields or methods of the Java class are considered. If the message is sent to an instance wrapper, only non-static fields or methods of the Java class of the wrapped object are considered. If the AmbientTalk selector uniquely identifies a method (i.e. no overloading on the method name is performed in Java), the matching method is invoked. All AmbientTalk arguments are converted to Java objects.  This is done by wrapping them into Java objects in the case of custom objects or by converting them to native Java values if possible (e.g. for the different number types). The Java return value is mapped back to an AmbientTalk value.
 ===== Overloading =====
+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.
+<code>
+Add code that shows how to disambiguate between overloaded methods
+</code>
 ===== Concurrency =====