at:tutorial:symbiosis
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at:tutorial:symbiosis [2007/04/06 16:09] – jdedecker | at:tutorial:symbiosis [2007/07/04 22:59] – jdedecker | ||
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This chapter explains how both sides of this symbiotic relationship between Java and AmbientTalk can be leveraged. The goal of this symbiotic relationship is to complement the advantages of both languages and to alleviate their disadvantages. | This chapter explains how both sides of this symbiotic relationship between Java and AmbientTalk can be leveraged. The goal of this symbiotic relationship is to complement the advantages of both languages and to alleviate their disadvantages. | ||
- | ===== Accessing Java classes | + | ===== 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). The figure below illustrates the different objects that play a part in the AmbientTalk/ | ||
+ | |||
+ | {{: | ||
+ | |||
+ | ===== Accessing Java from within AmbientTalk | ||
+ | |||
+ | |||
+ | ==== Accessing Java classes | ||
The complete set of classes that are available in the class path of a running JVM are accessible from AmbientTalk through the jlobby object. | The complete set of classes that are available in the class path of a running JVM are accessible from AmbientTalk through the jlobby object. | ||
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</ | </ | ||
- | ===== Creating Java objects | + | ==== Creating Java objects ==== |
- | Creating a new instance of the Vector | + | Java classes can be instantiated in AmbientTalk similar to how AmbientTalk objects are instantiated, |
+ | the Java constructor. For example, in the snippet code below **new** method is invoked | ||
< | < | ||
Line 32: | Line 41: | ||
</ | </ | ||
+ | ==== Invoking methods on Java objects ==== | ||
+ | Java objects appear as AmbientTalk objects whose field and method slots correspond to public instance-level fields and methods in the Java object. These are accessed or invoked as if they were plain AmbientTalk slots. | ||
- | ===== Using Java wrappers ===== | + | < |
+ | >1.to: 10 do: { |i| aVector.add(i) } | ||
+ | >> | ||
+ | > | ||
+ | >>< | ||
+ | </ | ||
- | ===== Overloading ===== | + | The AmbientTalk/ |
- | ===== Symbionts ===== | + | ==== Overloading |
+ | In Java methods can be overloaded based on the number of arguments and the types of the arguments. | ||
+ | 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' | ||
- | ===== Conversions | + | Selection of the correct overloaded method is done using the **cast** method. |
+ | |||
+ | < | ||
+ | > | ||
+ | >> | ||
+ | > | ||
+ | >> | ||
+ | </ | ||
+ | |||
+ | ===== Accessing AmbientTalk from within Java ===== | ||
+ | |||
+ | ==== Invoking AmbientTalk methods in Java ==== | ||
+ | Besides calling Java methods from within AmbientTalk it is also possible to call AmbientTalk methods from within Java. To illustrate this consider the code snippet shown below. | ||
+ | |||
+ | < | ||
+ | def SymbiosisDemo := jlobby.at.tutorial.SymbiosisDemo; | ||
+ | |||
+ | def showSymbiosis() { | ||
+ | def javaDemo := SymbiosisDemo.new(); | ||
+ | |||
+ | def atObject := object: { | ||
+ | def ping() { | ||
+ | system.println(" | ||
+ | javaDemo.run2(self); | ||
+ | }; | ||
+ | def pong() { | ||
+ | system.println(" | ||
+ | 42 | ||
+ | } | ||
+ | }; | ||
+ | |||
+ | javaDemo.run(atObject); | ||
+ | }; | ||
+ | |||
+ | self | ||
+ | </ | ||
+ | |||
+ | When an AmbientTalk object is passed as an argument to a Java method expecting an object of an interface type, the AmbientTalk object will appear to Java objects as a regular Java object implementing that interface. | ||
+ | |||
+ | < | ||
+ | package at.tutorial; | ||
+ | |||
+ | public class SymbiosisDemo { | ||
+ | public interface PingPong { | ||
+ | public int ping(); | ||
+ | public int pong(); | ||
+ | } | ||
+ | |||
+ | public int run(PingPong pp) { | ||
+ | return pp.ping(); | ||
+ | } | ||
+ | |||
+ | public int run2(PingPong pp) { | ||
+ | return pp.pong(); | ||
+ | } | ||
+ | |||
+ | } | ||
+ | </ | ||
- | ===== Thread-Actor Symbiosis ===== | + | If Java invokes a method declared in an interface with an overloaded method signature, all overloaded invocations are transformed into the same method invocation on the AmbientTalk object. In other words, the AmbientTalk object does not take the types into consideration. However, if the Java method is overloaded based on arity, the AmbientTalk programmer can take this into account in the parameter list of the corresponding AmbientTalk method, by means of a variable-argument list or optional parameters. Otherwise, the Java invocation may fail because of an arity mismatch. |
at/tutorial/symbiosis.txt · Last modified: 2013/05/17 20:25 by tvcutsem