[SOLVED] Is a Renjin Session reentrant

Is a Renjin Session reentrant

A Session is Renjin is not thread safe as described here, but is it reentrant safe ?

The scenario is calling from java engine.eval("...") that has a Java class that calls again the same engine.eval("..") method. Let's assume we've only one engine instance for the sake of simplicity.

Solution

Yes, that is possible.

Note that by calling engine.eval() on the original ScriptEngine instance, the expression will be evaluated in the global environment and the R function won't be able to see the R call stack that invoked the Java method.

You can also ask Renjin to pass the current Context to your Java method when invoked. For example:

class MyJavaClass {
   static SEXP estimate(@Current Context context, SEXP function) {
      return context.evaluate(FunctionCall.newCall(function, IntVector.valueOf(42)));
   }
}

And then:

import(MyJavaClass)
f <- function(x) x*2
MyJavaClass$estimate(f)  # 84