Hi Rinke,

I will try to take a look at your issue later (end of) this week.
It would be helpful if you can report against which version you are experiencing this behavior: current 2.0-SNAPSHOT or earlier milestone 2.0-M1 or 2.0-M0?

Thanks, Ate


On 2015-06-15 22:37, R.C. Hoekstra wrote:
Hi Woonsan, hi others,

At first, sorry for the late reply. I posted the issue in april, but didn't get 
a response in the first two weeks. Then I forgot about it (busy with other 
issues), and then just saw your reply, about a week ago.

Anyway, I've been thinking hard about the issue, and I think I now understand 
what is going on here.

Then again, sorry that my example wasn't so clear, at first. The problem is 
we're having very complicated scxml schemes working with several custom 
classes, and I tried to bring the example back to the basics, but probably just 
missed the key thing.

It basically comes to this, I discovered. Consider this scxml:

<state id="bla">
        <transition event="screening" target="cxr" />
</state>

<state id="cxr">
         <onentry>
                  <ntd:test id="CXR" />
         </onentry>
         <transition event="CXR.negative" target="untreated" />
         <transition event="CXR.positive" target="somethingelse"/>
</state>
<state id="untreated" />

The custom ntd:test tag fires a CXR.negative event.

Now the SCXMLListener reports this for the onentry's and onexit's

...
0.000: Human#0 ONEXIT bla
0.000: Human#0 ONEXIT cxr
0.000: Human#0 ONENTRY untreated
0.000: Human#0 ONENTRY cxr

Note that the problem is that the cxr state's onexit is reported first, and 
only at the end of the chain the onentry for cxr is reported. The order should 
have been this:
onexit bla
onentry cxr
onexit cxr
onentry untreated

This doesn't happen with logs, it only happens with my own custom action.

The custom action does some tests, and on basis of the state the engine is in, 
and has been in (and some other stuff) the outcome is positive or negative.
It then sends back a positive or a negative event, via this code:


             TriggerEvent[] evts = { new TriggerEvent(stateMachineEvent, 
TriggerEvent.SIGNAL_EVENT, payload) };
             scxmlExecutorInstance.triggerEvents(evts);

where stateMachineEvent is either "<id>.positive" or "<id>.negative".


So what happens is this:
1) state machine exits "bla" -> onexit bla is reported by listener
2) state machine enters "cxr", and goes straight to onentry
3) custom action is executed, scxmlExecutorInstance.triggerEvents is called with 
"CXR.negative".
4) Still as part of the custom action, the event is caught in the transition tag, and 
state machine directed to "untreated"
5) the "cxr" state is exited -> onexit cxr reported by listener
6) "untreated" state entered -> onentry untreated reported by listener
7) Now that the state of the scxmlExecutoerInstance.triggerEvents call is 
reached, only now the custom Actions's execute method is returned.
8) only after the execute method of the custom action returned, the onentry block of 
"cxr" is finished, and only after that the "onentry cxr" is reported by the 
listener.


So, conclusion:

A) does this scenario make sense?
B) would you consider this as a bug? The behavior is at least tricky...


Thanks, Rinke




________________________________________________________________________________________

Hi Rinke,

Did you run with commons-scxml2-2.0-SNAPSHOT?
I've tried to run the following similar to yours on latest revision, but the 
result seems
different from what you're seeing:

<?xml version="1.0" ?>
<scxml xmlns="http://www.w3.org/2005/07/scxml";
        version="1.0"
        datamodel="jexl"
        initial="test1">

   <state id="test1" initial="test1.1">

     <state id="test1.1">
       <onentry>
         <log expr="'logging in test1.1'" />
       </onentry>
       <transition event="test1.1.positive" target="test1.2"/>
     </state>

     <state id="test1.2">
       <onentry>
         <log expr="'logging in test1.2'" />
       </onentry>
       <transition event="test1.2.positive" target="test1.3"/>
     </state>

     <state id="test1.3">
       <onentry>
         <log expr="'logging in test1.3'" />
       </onentry>
     </state>

   </state>

</scxml>

I removed the custom action tags and replaced the script tag with simple log 
tags.
And I see the following when I tested it with the stanadlone tool [1]:

$ ./scxml.sh test.scxml
<?xml version="1.0" encoding="UTF-8"?><scxml 
xmlns="http://www.w3.org/2005/07/scxml";
xmlns:cs="http://commons.apache.org/scxml"; version="1.0" initial="test1" 
datamodel="jexl">
---- >8 ---- >8 ----
</scxml>

May 05, 2015 11:44:51 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onEntry
INFO: enter /test1
May 05, 2015 11:44:51 PM org.apache.commons.scxml2.model.Log execute
INFO: null: logging in test1.1
May 05, 2015 11:44:51 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onEntry
INFO: enter /test1/test1.1
test1.1.positive
May 05, 2015 11:45:16 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onExit
INFO: exit /test1/test1.1
May 05, 2015 11:45:16 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onTransition
INFO: transition (event = test1.1.positive, cond = null, from = /test1/test1.1, 
to = /test1/test1.2)
May 05, 2015 11:45:16 PM org.apache.commons.scxml2.model.Log execute
INFO: null: logging in test1.2
May 05, 2015 11:45:16 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onEntry
INFO: enter /test1/test1.2
test1.2.positive
May 05, 2015 11:45:47 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onExit
INFO: exit /test1/test1.2
May 05, 2015 11:45:47 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onTransition
INFO: transition (event = test1.2.positive, cond = null, from = /test1/test1.2, 
to = /test1/test1.3)
May 05, 2015 11:45:47 PM org.apache.commons.scxml2.model.Log execute
INFO: null: logging in test1.3
May 05, 2015 11:45:47 PM org.apache.commons.scxml2.env.SimpleSCXMLListener 
onEntry
INFO: enter /test1/test1.3

(I typed 'test1.1.positive' and 'test1.2.positive' to trigger those events 
manually.)

So, the execution order is as follows:
1. enter into test1 state
2. execute actions in onentry of test1.1 state
3. enter into test1.1 state and wait
4. 'test1.1.positive' event triggered manually
5. exit from test1.1 state
6. transition from test1.1 to test 1.2 state
7. execute actions in onentry of test1.2 state
8. enter into test1.2 state
9. 'test1.2.positive' event triggered manually
10. exit from test1.2 state
11. transition from test1.2 to test1.3 state
12. execute actions in onentry of test1.3 state
13. enter into test1.3 state

I don't think <script> action would be different from <log> action in execution
ordering, so I think you're seeing a different result on your end for some 
reason. Maybe you
can try to find what the difference comes from?

Regards,

Woonsan

[1] http://commons.apache.org/proper/commons-scxml/guide/testing-standalone.html


--------------------------------------------
On Fri, 4/17/15, R.C. Hoekstra <r.c.hoeks...@erasmusmc.nl> wrote:

  Subject: [scxml] bug with script in combination of a chain of transitions
  To: "user@commons.apache.org" <user@commons.apache.org>
  Date: Friday, April 17, 2015, 4:12 AM

  Dear people at scxml,

  I found a bug in the scxml commons project.

  Consider this scxml file:

      <state id="test1" initial="test1.1">
          <state id="test1.1">
              <onentry>

  <ntd:test id="test1.1" isIn="test1.1" />

  <script> agent.storeInMemory("test1.1");
  </script>
              </onentry>
              <transition
  event="test1.1.positive" target="test1.2"/>
          </state>
          <state id="test1.2">
              <onentry>

  <ntd:test id="test1.2" isIn="test1.1" memory="true"
  />
              </onentry>
              <transition
  event="test1.2.positive" target="test1.3"/>
          </state>
          <state id="test1.3"/>
      </state>

  There is a custom tag, which simply tests if the state
  machine is at present in the state specified in the "isIn"
  attribute. If it is, it sends an event <id>.positive,
  else it sends <id>.negative.
  The purpose of this is that we needed a memory: a test that
  the state machine has at any moment been in a certain state.
  That is done via the script tag: via the
  agent.storeInMemory("test1.1") call, the test1.1 state is
  stored in the memory of the agent, and ntd:test tag
  considers this memory if the memory=true attribute is
  specified. As the state test1.1 is stored in memory while
  being in state test1.1, the test of test1.2 should return
  positive, and the test1.2.positive event should be send.

  However, this tests fails.
  The problem is that the script tag appears to be only
  executed AFTER the chain of all transitions has been
  executed and finished, and so the call of the script is too
  late for the test.  I had expected the script tag to be
  executed at entering state test1.1, and not only after
  having passed test1.1 and being already in test1.2


  The order of entries is also weird: the log shows this
  order:

  onentry: test1
  onentry: test1.2
  onentry: test1.1

  So you should expect that the onentry for 1.2 happens after
  1.1, but it is reversed.

  best regards, Rinke


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