[dbcp] - How to programmatically check the pool status?
Hi all, I'm using Tomcat 6.0.26 and its default dbcp connection pooling system (tomcat-dbcp.jar inside the default installation dir) My question is: How could I check programmatically the connection pool status ? For example inside a catch of some exception related to some database issues I would like to log some info like the number of currenlty open connections, idle etc... Thanks in advance and best regards Raffaele Gambelli - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
SCXML2 Serialization
Hi all,
I would like to know the best practice to serialize/deserialize SCXML fsm.
I do this during the creation of the SCXML executor, scInstace is the
serialized context:
ListCustomAction customActions = new ArrayListCustomAction();
CustomAction ca =
new CustomAction(http://my.custom-actions.domain/CUSTOM1;,
hello, Hello.class);
customActions.add(ca);
JexlEvaluator evaluator = new JexlEvaluator();
try {
scxml = SCXMLReader.read(StopWatch.class.getClassLoader().
} catch (Exception e) {
e.printStackTrace();
throw e;
}
executor = null;
try {
executor = new SCXMLExecutor(evaluator, null, new
SimpleErrorReporter());
if (scInstance != null) {
// serialized context use it
executor.attachInstance(scInstance);
executor.registerInvokerClass(x-test, DummyInvoker.class);
executor.setStateMachine(scxml);
executor.go();
setInitialState(executor, paused);
} else {
// new context
Context rootContext = new JexlContext();
rootContext.set(var1, value1);
executor.registerInvokerClass(x-test, DummyInvoker.class);
executor.setStateMachine(scxml);
executor.setRootContext(rootContext);
executor.go();
}
} catch (ModelException me) {
// Executor initialization failed, because the
// state machine specified has inconsistencies
me.printStackTrace();
}
I serialize executor.detachInstance(). It's seem to work, but is it the right
way to restart a SCXML 'session' ?
Thanks
Francis.
-
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Re: SCXML2 Serialization
Hi Francis,
I think the best practices are to serialize either o.a.c.s.SCXMLExecutor [1] or
o.a.c.s.model.SCXML instances. Both cases are well-maintained in test code. [2]
In your case, you can probably (de)serialize SCXMLExecutor instance directly to
store/load the execution context.
Also, as far as I can see, SCXMLExecutor doesn't provide #(at|de)tachInstance()
methods and I don't think it would do even later because SCInstance doesn't
necessarily have full information about the current execution context.
So, please (de)serialize the SCXMLExecutor instance instead.
Cheers,
Woonsan
[1] http://commons.apache.org/proper/commons-scxml/faq.html#serializability
[2]
http://svn.apache.org/repos/asf/commons/proper/scxml/trunk/src/test/java/org/apache/commons/scxml2/SCXMLTestHelper.java
On Wednesday, April 16, 2014 9:07 AM, ten...@free.fr ten...@free.fr wrote:
Hi all,
I would like to know the best practice to serialize/deserialize SCXML fsm.
I do this during the creation of the SCXML executor, scInstace is the
serialized context:
ListCustomAction customActions = new ArrayListCustomAction();
CustomAction ca =
new CustomAction(http://my.custom-actions.domain/CUSTOM1;,
hello, Hello.class);
customActions.add(ca);
JexlEvaluator evaluator = new JexlEvaluator();
try {
scxml = SCXMLReader.read(StopWatch.class.getClassLoader().
} catch (Exception e) {
e.printStackTrace();
throw e;
}
executor = null;
try {
executor = new SCXMLExecutor(evaluator, null, new
SimpleErrorReporter());
if (scInstance != null) {
// serialized context use it
executor.attachInstance(scInstance);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.go();
setInitialState(executor, paused);
} else {
// new context
Context rootContext = new JexlContext();
rootContext.set(var1, value1);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.setRootContext(rootContext);
executor.go();
}
} catch (ModelException me) {
// Executor initialization failed, because the
// state machine specified has inconsistencies
me.printStackTrace();
}
I serialize executor.detachInstance(). It's seem to work, but is it the right
way to restart a SCXML 'session' ?
Thanks
Francis.
-
To unsubscribe, e-mail: user-unsubscr...@commons.apache.org
For additional commands, e-mail: user-h...@commons.apache.org
Re: SCXML2 Serialization
Hi Francis,
There are a few things not right or needed in your approach below.
I've provided comments inline.
On 16-04-14 15:07, ten...@free.fr wrote:
Hi all,
I would like to know the best practice to serialize/deserialize SCXML fsm.
I do this during the creation of the SCXML executor, scInstace is the
serialized context:
ListCustomAction customActions = new ArrayListCustomAction();
CustomAction ca =
new CustomAction(http://my.custom-actions.domain/CUSTOM1;,
hello, Hello.class);
customActions.add(ca);
JexlEvaluator evaluator = new JexlEvaluator();
try {
scxml = SCXMLReader.read(StopWatch.class.getClassLoader().
} catch (Exception e) {
e.printStackTrace();
throw e;
}
executor = null;
try {
executor = new SCXMLExecutor(evaluator, null, new
SimpleErrorReporter());
While you can recreate SCXMLExecutor each time, this is not the intended usage.
The SCXMLExecutor holds the external event queue. If you are using Invokers, and
you *do* in your example, then these might still be (kept) 'running' while the
state machine itself is currently stabilized. So after a return from go() or
triggerEvent(). And these invokers might send back events into the external
queue for further processing. So then you should keep hold of the SCXMLExecutor
instance, across serialization/deserialization of the SCInstance.
If you don't use Invokers, or don't expect them to still be running after the
state machine stabilized (which might be the case in your example?) then I guess
recreating the SCXMLExecutor is fine. But then you should not set the
statemachine again (after attachIstance) as that will re-initialize the
SCInstance itself. Same goes for calling go() again or otherwise re-initializing
the current state. What would be the point of serializing in that case anyway?
Note also, the statemachine is automatically serialized together with the
SCInstance, so you actually don't need to set it again.
if (scInstance != null) {
// serialized context use it
executor.attachInstance(scInstance);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
this shouldn't be done as it will re-initialize the SCInstance state
executor.go();
this does the same, so definitely shouldn't be done either, because this way
there is no 'state' retained from what you serialized before
setInitialState(executor, paused);
same goes for this: if you re-attach the instance, I assume you would want to
'return' in the same state you left off, right?
} else {
// new context
Context rootContext = new JexlContext();
rootContext.set(var1, value1);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.setRootContext(rootContext);
executor.go();
This initialization part is fine
}
} catch (ModelException me) {
// Executor initialization failed, because the
// state machine specified has inconsistencies
me.printStackTrace();
}
I serialize executor.detachInstance(). It's seem to work, but is it the right
way to restart a SCXML 'session' ?
See comments above. You're almost good but especially need to think about the
Invoker use-cases and if that might require you to keep hold of the
SCXMLExecutor instance.
Regards, Ate
Thanks
Francis.
-
To unsubscribe, e-mail: user-unsubscr...@commons.apache.org
For additional commands, e-mail: user-h...@commons.apache.org
-
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Re: SCXML2 Serialization
Hi Woonsan,
On 16-04-14 15:49, Woonsan Ko wrote:
Hi Francis,
I think the best practices are to serialize either o.a.c.s.SCXMLExecutor [1] or
o.a.c.s.model.SCXML instances. Both cases are well-maintained in test code. [2]
Actually, since the last milestone SCXMLExecutor no longer is serializable :)
See also https://issues.apache.org/jira/browse/SCXML-197
I still need to provide updated documentation for this, but the SCXMLTestHelper
[2] class has been (and had to be) updated for this changed usage.
In your case, you can probably (de)serialize SCXMLExecutor instance directly to
store/load the execution context.
Also, as far as I can see, SCXMLExecutor doesn't provide #(at|de)tachInstance()
methods and I don't think it would do even later because SCInstance doesn't
necessarily have full information about the current execution context.
So, please (de)serialize the SCXMLExecutor instance instead.
You need to update to the latest milestone 1 or trunk, then you'll see the new
attach/detach instance features ;)
Cheers,
Woonsan
[1] http://commons.apache.org/proper/commons-scxml/faq.html#serializability
[2]
http://svn.apache.org/repos/asf/commons/proper/scxml/trunk/src/test/java/org/apache/commons/scxml2/SCXMLTestHelper.java
On Wednesday, April 16, 2014 9:07 AM, ten...@free.fr ten...@free.fr wrote:
Hi all,
I would like to know the best practice to serialize/deserialize SCXML fsm.
I do this during the creation of the SCXML executor, scInstace is the
serialized context:
ListCustomAction customActions = new ArrayListCustomAction();
CustomAction ca =
new CustomAction(http://my.custom-actions.domain/CUSTOM1;,
hello, Hello.class);
customActions.add(ca);
JexlEvaluator evaluator = new JexlEvaluator();
try {
scxml = SCXMLReader.read(StopWatch.class.getClassLoader().
} catch (Exception e) {
e.printStackTrace();
throw e;
}
executor = null;
try {
executor = new SCXMLExecutor(evaluator, null, new
SimpleErrorReporter());
if (scInstance != null) {
// serialized context use it
executor.attachInstance(scInstance);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.go();
setInitialState(executor, paused);
} else {
// new context
Context rootContext = new JexlContext();
rootContext.set(var1, value1);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.setRootContext(rootContext);
executor.go();
}
} catch (ModelException me) {
// Executor initialization failed, because the
// state machine specified has inconsistencies
me.printStackTrace();
}
I serialize executor.detachInstance(). It's seem to work, but is it the right
way to restart a SCXML 'session' ?
Thanks
Francis.
-
To unsubscribe, e-mail: user-unsubscr...@commons.apache.org
For additional commands, e-mail: user-h...@commons.apache.org
-
To unsubscribe, e-mail: user-unsubscr...@commons.apache.org
For additional commands, e-mail: user-h...@commons.apache.org
Re: SCXML2 Serialization
On Wednesday, April 16, 2014 9:57 AM, Ate Douma a...@douma.nu wrote:
Hi Woonsan,
On 16-04-14 15:49, Woonsan Ko wrote:
Hi Francis,
I think the best practices are to serialize either o.a.c.s.SCXMLExecutor [1]
or o.a.c.s.model.SCXML instances. Both cases are well-maintained in test
code. [2]
Actually, since the last milestone SCXMLExecutor no longer is serializable :)
See also https://issues.apache.org/jira/browse/SCXML-197
I still need to provide updated documentation for this, but the
SCXMLTestHelper
[2] class has been (and had to be) updated for this changed usage.
In your case, you can probably (de)serialize SCXMLExecutor instance directly
to store/load the execution context.
Also, as far as I can see, SCXMLExecutor doesn't provide
#(at|de)tachInstance() methods and I don't think it would do even later
because SCInstance doesn't necessarily have full information about the
current execution context.
So, please (de)serialize the SCXMLExecutor instance instead.
You need to update to the latest milestone 1 or trunk, then you'll see the new
attach/detach instance features ;)
Ah, sorry. I haven't updated the code for a while. My comment was based on
outdated information then..
Thanks,
Woonsan
Cheers,
Woonsan
[1] http://commons.apache.org/proper/commons-scxml/faq.html#serializability
[2]
http://svn.apache.org/repos/asf/commons/proper/scxml/trunk/src/test/java/org/apache/commons/scxml2/SCXMLTestHelper.java
On Wednesday, April 16, 2014 9:07 AM, ten...@free.fr ten...@free.fr
wrote:
Hi all,
I would like to know the best practice to serialize/deserialize SCXML fsm.
I do this during the creation of the SCXML executor, scInstace is the
serialized context:
ListCustomAction customActions = new
ArrayListCustomAction();
CustomAction ca =
new
CustomAction(http://my.custom-actions.domain/CUSTOM1;,
hello, Hello.class);
customActions.add(ca);
JexlEvaluator evaluator = new JexlEvaluator();
try {
scxml = SCXMLReader.read(StopWatch.class.getClassLoader().
} catch (Exception e) {
e.printStackTrace();
throw e;
}
executor = null;
try {
executor = new SCXMLExecutor(evaluator, null, new
SimpleErrorReporter());
if (scInstance != null) {
// serialized context use it
executor.attachInstance(scInstance);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.go();
setInitialState(executor, paused);
} else {
// new context
Context rootContext = new JexlContext();
rootContext.set(var1, value1);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.setRootContext(rootContext);
executor.go();
}
} catch (ModelException me) {
// Executor initialization failed, because the
// state machine specified has inconsistencies
me.printStackTrace();
}
I serialize executor.detachInstance(). It's seem to work, but is it the
right way to restart a SCXML 'session' ?
Thanks
Francis.
-
To unsubscribe, e-mail: user-unsubscr...@commons.apache.org
For additional commands, e-mail: user-h...@commons.apache.org
-
To unsubscribe, e-mail: user-unsubscr...@commons.apache.org
For additional commands, e-mail: user-h...@commons.apache.org
-
To unsubscribe, e-mail: user-unsubscr...@commons.apache.org
For additional commands, e-mail: user-h...@commons.apache.org
[dbcp] - How to programmatically check the pool status?
Hi all, I'm using Tomcat 6.0.26 and its default dbcp connection pooling system (tomcat-dbcp.jar inside the default installation dir) My question is: How could I check programmatically the connection pool status ? For example inside a catch of some exception related to some database issues I would like to log some info like the number of currenlty open connections, idle etc... Thanks in advance and best regards -- Raffaele Gambelli _*Gecod s.r.l.*_ http://gecod.com/it/contatti/index.do /Development Area/ phone: +39 051 4075795 fax: +39 051.9525291 e-mail: _rgambelli@gecod.com_ mailto:rgambe...@gecod.com web: _www.gecod.com_ http://www.gecod.com/ skype-id: _rgambelli.gecod_ skype:rgambelli.gecod?add /Gecod s.r.l. - Tutti i diritti riservati./ /Il presente messaggio e i documenti allegati possono contenere informazioni di carattere confidenziale o riservato. Qualora non foste i destinatari, vogliate immediatamente informarci via e-mail ed eliminare il messaggio, con gli eventuali allegati senza trattenerne copia./ /Gecod s.r.l. - All rights reserved./ /This message and the enclosed documents may contain information which is confidential or privileged. If you are not the intended recipient, please advise the sender immediately by reply e-mail and delete this message and any attachments without retaining a copy./
Re: [dbcp] - How to programmatically check the pool status?
On 4/16/14, 2:33 AM, Raffaele Gambelli wrote: Hi all, I'm using Tomcat 6.0.26 and its default dbcp connection pooling system (tomcat-dbcp.jar inside the default installation dir) My question is: How could I check programmatically the connection pool status ? For example inside a catch of some exception related to some database issues I would like to log some info like the number of currenlty open connections, idle etc... Have a look at the javadoc for BasicDatasource for the version that tomcat 6 is using (some 1.x version). There are getters for the number of active and idle connections. You may need to cast the reference that tomcat gives you to the datasource to use these methods. You may want to ask about this on the tomcat user list. Phil Thanks in advance and best regards Raffaele Gambelli - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
RE: SCXML2 Serialization
Thanks for your reply Ate.
I want to serialize/deserialize a SCXML 'session' for this use case :
Into a transactional server, a request is processed by a thread. An ID is
retrieved from the message, with this ID the server loads a context (from a
redis store) and instantiates a new 'Executor' with it's associated SCXML file
and saved instance.
I'll use invokers to call external functions or new a SCXML 'processor', I
don't expect them to still be running after the state machine stabilized.
You said : But then you should not set the statemachine again (after
attachInstance) as that will re-initialize the SCInstance itself
so I don't have to do this executor.setStateMachine(scxml);because scxml is
serialized with the scInstance. But if I need to register a listener
(addListener) or if I have custom actions, are they serialized too?
In the example I do 'setInitialState(executor, paused);' because the call to
go resets the state and I know that 'paused' is the last state. Of course I
want to 'return' in the same state I left off. Without a call of the go
function, the state machine seems to be frozen.
Thanks,
Regards
Francis.
--
Hi Francis,
There are a few things not right or needed in your approach below.
I've provided comments inline.
On 16-04-14 15:07, ten...@free.fr wrote:
Hi all,
I would like to know the best practice to serialize/deserialize SCXML fsm.
I do this during the creation of the SCXML executor, scInstace is the
serialized context:
ListCustomAction customActions = new ArrayListCustomAction();
CustomAction ca =
new CustomAction(http://my.custom-actions.domain/CUSTOM1;,
hello, Hello.class);
customActions.add(ca);
JexlEvaluator evaluator = new JexlEvaluator();
try {
scxml = SCXMLReader.read(StopWatch.class.getClassLoader().
} catch (Exception e) {
e.printStackTrace();
throw e;
}
executor = null;
try {
executor = new SCXMLExecutor(evaluator, null, new
SimpleErrorReporter());
While you can recreate SCXMLExecutor each time, this is not the intended usage.
The SCXMLExecutor holds the external event queue. If you are using Invokers,
and you *do* in your example, then these might still be (kept) 'running' while
the state machine itself is currently stabilized. So after a return from go()
or triggerEvent(). And these invokers might send back events into the external
queue for further processing. So then you should keep hold of the SCXMLExecutor
instance, across serialization/deserialization of the SCInstance.
If you don't use Invokers, or don't expect them to still be running after the
state machine stabilized (which might be the case in your example?) then I
guess recreating the SCXMLExecutor is fine. But then you should not set the
statemachine again (after attachIstance) as that will re-initialize the
SCInstance itself. Same goes for calling go() again or otherwise
re-initializing the current state. What would be the point of serializing in
that case anyway?
Note also, the statemachine is automatically serialized together with the
SCInstance, so you actually don't need to set it again.
if (scInstance != null) {
// serialized context use it
executor.attachInstance(scInstance);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
this shouldn't be done as it will re-initialize the SCInstance state
executor.go();
this does the same, so definitely shouldn't be done either, because this way
there is no 'state' retained from what you serialized before
setInitialState(executor, paused);
same goes for this: if you re-attach the instance, I assume you would want to
'return' in the same state you left off, right?
} else {
// new context
Context rootContext = new JexlContext();
rootContext.set(var1, value1);
executor.registerInvokerClass(x-test,
DummyInvoker.class);
executor.setStateMachine(scxml);
executor.setRootContext(rootContext);
executor.go();
This initialization part is fine
}
} catch (ModelException me) {
// Executor initialization failed, because the
// state machine specified has inconsistencies
me.printStackTrace();
}
I serialize executor.detachInstance(). It's seem to work, but is it the right
way to restart a SCXML 'session' ?
See comments above. You're almost good but especially need to think about the
Invoker use-cases and if that might require you to
SCXML2 Serialization
Hi Ate, I put Simple1.java and Simple1.xml here : http://tendaf.free.fr/ When I run the program (second time) the fsm is frozen : First time : After creation [startIngTrs.processMsg is running : true message:message1 serialize.. Process finished with exit code 0 Second time : Loading simple1 Deserialize.. After creation [startIngTrs.waitMsg is running : false message:message2 Process finished with exit code 0 Thanks, Regards Francis. Thanks for your reply Ate. I want to serialize/deserialize a SCXML 'session' for this use case : Into a transactional server, a request is processed by a thread. An ID is retrieved from the message, with this ID the server loads a context (from a redis store) and instantiates a new 'Executor' with it's associated SCXML file and saved instance. I'll use invokers to call external functions or new a SCXML 'processor', I don't expect them to still be running after the state machine stabilized. You said : But then you should not set the statemachine again (after attachInstance) as that will re-initialize the SCInstance itself so I don't have to do this executor.setStateMachine(scxml);because scxml is serialized with the scInstance. But if I need to register a listener (addListener) or if I have custom actions, are they serialized too? In the example I do 'setInitialState(executor, paused);' because the call to go resets the state and I know that 'paused' is the last state. Of course I want to 'return' in the same state I left off. Without a call of the go function, the state machine seems to be frozen. Thanks, Regards Francis. - To unsubscribe, e-mail: user-unsubscr...@commons.apache.org For additional commands, e-mail: user-h...@commons.apache.org
