Hi Geert,
Thanks for your help.
1. There should really be a $ in the inner class name as it is a
string passed to loadClass(), not a class name in java source code.
2. The exception was thrown during bytecode rewrite of my
Sequence.execute() method. This snippet of ResumableMethodAdapter
throws the exception:
...
else if (mConfig.getCallMethodName().equals(name) && ...
{
// store the call target
debugMessage("CONT: call : storing call target");
mMethodVisitor.visitVarInsn(ASTORE, mCallTargetIndex);
// pop the ALOAD opcode off the stack
debugMessage("CONT: call : undoing method call");
mMethodVisitor.visitInsn(POP);
TypesContext context = mTypes.nextPauseContext();
Stack<String> stack = context.getStackClone();
stack.pop(); <-------
debugMessage("CONT: call : saving operand stack");
saveOperandStack(stack);
...
I interpreted this as me using call() in a location where it is not
allowed. (and maybe it is not allowed)
Allthough I have not enough understanding of the code I tried
modifying it like this:
if(!stack.empty())
stack.pop();
This made my call-answer sample run!
Could you comment on what is happening?
3. About the rife-workflow project: I was surprised to see that it
uses multiple threads. What is the rationale for this? My goal is to
perform a sequence of blocking calls, all on the same thread to avoid
synchronization issues due to preemtive thread switching. I guess the
threads in rife-workflow don't have a lot of interaction because they
just run until a blocking action is performed and then they exit.
Still I would think using just one thread is also possible.
On Nov 14, 8:51 pm, Geert Bevin <[EMAIL PROTECTED]> wrote:
> Hi Peter,
>
> I created a similar project, called RIFE/Workflow. You can check it
> out from SVN:http://svn.rifers.org/rife-workflow/trunk/
>
> It uses continuations for a workflow engine and also has renamed
> 'call' to 'waitForEvent', which makes more sense.
>
> In your case, "CallAnswerTest$Sequence" is not a valid classname in
> the Java language. Inner classes are also referenced with a dot, hence
> I think that "CallAnswerTest.Sequence" should work.
>
> Hope this helps,
>
> Geert
>
> On 14 Nov 2007, at 17:58, peter wrote:
>
>
>
>
>
>
>
> > I am exploring rife continuations for use in an embedded event driven
> > environment (J2ME, foundation profile, which is java 1.3 based). I can
> > now run a small app using just pause() but have problems doing call-
> > answer.
>
> > The purpose is to perform a sequence of blocking calls:
>
> > public static class Sequence extends AbstractContinuableObject
> > {
> > public void execute()
> > {
> > String reply = (String) call(CallTarget.class);
> > System.out.println("reply=" + reply);
>
> > reply = (String) call(CallTarget.class);
> > System.out.println("reply=" + reply);
>
> > reply = (String) call(CallTarget.class);
> > System.out.println("reply=" + reply);
> > }
> > }
>
> > where CallTarget (which does the blocking call) looks like this:
>
> > public static class CallTarget extends AbstractContinuableObject
> > {
> > static int count = 0;
>
> > public void execute()
> > {
> > pause();
> > answer("hello " + count++);
> > }
> > }
>
> > The Sequence is started like this:
>
> > MyContinuableRunner runner = new MyContinuableRunner();
> > String id = runner.start("CallAnswerTest$Sequence"/
> > *Sequence.class.getName()*/);
>
> > I wrote an URLContinuableClassloader derrived from URLClassloader and
> > which does about the same thing as BasicContinuableClassLoader. The
> > jvm uses URLContinuableClassloader as application class loader so it
> > will load all my application classes.
>
> > When attempting to load Sequence I get following stacktrace:
>
> > transforming CallAnswerTest$Sequence
> > Exception in thread "main" java.lang.ClassNotFoundException:
> > CallAnswerTest$Sequence
> > java.util.EmptyStackException
> > at java.util.Stack.pop(Stack.java:77)
> > at
> > com
> > .uwyn
> > .rife
> > .continuations
> > .instrument
> > .ResumableMethodAdapter.visitMethodInsn(ResumableMethodAdapter.java:
> > 378)
> > at com.uwyn.rife.asm.ClassReader.accept(ClassReader.java:1340)
> > at com.uwyn.rife.asm.ClassReader.accept(ClassReader.java:395)
> > at
> > com
> > .uwyn
> > .rife
> > .continuations
> > .instrument
> > .ContinuationsBytecodeTransformer
> > .transformIntoResumableBytes(ContinuationsBytecodeTransformer.java:
> > 68)
> > at
> > com
> > .uwyn
> > .rife
> > .continuations
> > .basic
> > .URLContinuableClassLoader.loadClass(URLContinuableClassLoader.java:
> > 195)
> > at
> > com
> > .uwyn
> > .rife
> > .continuations
> > .basic.BasicContinuableRunner.run(BasicContinuableRunner.java:
> > 171)
> > at
> > com
> > .uwyn
> > .rife
> > .continuations
> > .basic.BasicContinuableRunner.start(BasicContinuableRunner.java:
> > 85)
> > at CallAnswerTest.go(CallAnswerTest.java:59)
> > at CallAnswerTest.main(CallAnswerTest.java:50)
>
> > I guess I am missing something basic regarding the use of call-answer.
> > Who can give me some pointers on how to use call-answer outide the
> > domain of web apps?
>
> --
> Geert Bevin
> Terracotta -http://www.terracotta.org
> Uwyn "Use what you need" -http://uwyn.com
> RIFE Java application framework -http://rifers.org
> Music and words -http://gbevin.com- Hide quoted text -
>
> - Show quoted text -
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