Arno kindly fixed the Janino mailing list archive, as promised, so here's the link to my thread there: [1] http://old.nabble.com/Janino-and-OSGi--to33030424.html Regards, Glyn On 8 Jan 2012, at 18:50, Arno Unkrig wrote:
Hi Glyn and everybody else,
one quick note here: There is no difference between "ScriptEvaluator" and "ExpressionEvaluator" (other than that the former compiles a method body and the latter an expression). Initially, both came with a set of constructors with varying parameter counts and types, but because the configuration possibilities grew over time, the recommended usage pattern is now to call the parameterless constructor, then a series of setters, and then (one of) the "cook()" methods.
I also wonder why LOGBACK switched from ExpressionEvaluator
https://github.com/ceki/logback/blob/6c5ba501831d19879e6865f795a1c294ad25bf7...
to ScriptEvaluator
https://github.com/ceki/logback/blob/06a5b692f14560636bd92d7bd7cf1f85830f4e5...
anyway!? That's a huge semantical change...
Am 05.01.2012 13:09, schrieb Glyn Normington:
I am attempting to get Janino 2.6.1 working with Logback 0.9.28 (or later, but that's the version we are using in Eclipse Virgo right now) - see [0] for background. Unfortunately Janino ends up using the thread context class loader as its "parent" class loader and fails with a runtime exception. I have discussed this ([1]) on the Janino mailing list and it seems that it is necessary to set the parent class loader in Janino. I am somewhat at the mercy of Logback here.
The surprising thing is that the code in Logback 0.9.24 looked pretty usable in this respect. JaninoEventEvaluator.start had the following sequence:
ClassLoader cl = context.getClass().getClassLoader(); ee = new ExpressionEvaluator(getDecoratedExpression(), EXPRESSION_TYPE, getParameterNames(), getParameterTypes(), THROWN_EXCEPTIONS, cl);
thus setting the parent class loader to a value which I could ensure would be capable of loading the necessary types.
In 0.9.28 this code has been replaced by:
scriptEvaluator = new ScriptEvaluator(getDecoratedExpression(), EXPRESSION_TYPE, getParameterNames(), getParameterTypes(), THROWN_EXCEPTIONS);
which causes the current TCCL to be used as the parent class loader and ultimately results in Janino failing.
I can't control the TCCL that happens to be in use when start is called as that is driven out of a logging call which can come from an arbitrary thread.
I found the relevant commit ([2]), but I can't tell from that why this specific change was made.
If it is absolutely necessary to use ScriptEvaluator rather than ExpressionEvaluator, the following code sequence (based on a suggestion from Arno Unkrig) would reproduce the parent class loader behaviour of 0.9.24:
ClassLoader cl = context.getClass().getClassLoader(); scriptEvaluator = new ScriptEvaluator(); scriptEvaluator.setParentClassLoader(cl); scriptEvaluator.setReturnType(EXPRESSION_TYPE); scriptEvaluator.setParameterNames(getParameterNames()); scriptEvaluator.setParameterTypes(getParameterTypes()); scriptEvaluator.setThrownExceptions(THROWN_EXCEPTIONS); scriptEvaluator.cook(getDecoratedExpression());
The alternative of using ExpressionEvaluator is much neater and seems to be close to the ScriptEvaluator variant since ExpressionEvaluator extends ScriptEvaluator.
Any suggestions gratefully received.
Regards, Glyn [0] https://bugs.eclipse.org/bugs/show_bug.cgi?id=333920 [1] mailing list archive link currently broken - if I can get a link to it, I'll post this later [2] https://github.com/ceki/logback/commit/06a5b692f14560636bd92d7bd7cf1f85830f4...