Say I have a Task object, with an Execute method. This method has one to several steps, each of which requires a user to click a 'Continue' button, e.g. when Execute is invoked, the Task tells it's container (a Windows form in this case) to display an introductory message, and wait for a button click, before continuing with step 2, notifying the user that what is taking place and performing some work.
I don't want the controller to have to be aware of the steps in the task, either implicitly, through e.g. calling Execute(Steps.ShowIntro), Execute(Steps.PerformTask) etc. or explicitly, with more than one Execute method, e.g. ExecuteIntro(), ExecuteTask(), etc.
Currently I'm using a Phase enumeration to determine which action to carry out when the Continue button is clicked:
show phase 1 intro.
set current_phase = PhaseOne.
on continue_button click
switch current_phase
case PhaseOne:
show phase 1 'Now doing:' message.
execute phase 1 task.
show phase 2 intro.
set phase to PhaseTwo.
case PhaseTwo:
show phase 2 'Now doing:' message.
execute phase 2 task.
show phase 3 intro.
set phase to PhaseThree.
Why don't you simply implement as many classes with Execute method as steps and put instances of those classes in the queue.
By pressing "Continue" you will take another instance of the class with Execute and call it.
class Task
method execute()
foreach task in queue execute task
method addSubTask( task )
add task to queue
class ShowIntroSubTask extends Task
class ExecuteIntroSubTask extends Task
Mykola's answer sounds good, but if you'd like an alternative, consider passing in a ConfirmContinuation callback, which the Execute could use as needed (e.g. on step transitions). If you wanted to keep things abstract, just call it something like NextStep and leave the semantics up to the container.
Related
Can we define our own skip and submit button instead of using the predefined one? Especially when we only have 1 task per task suit? I just want to change it because in my case there is more preferable variant
Unfortunately, there is no function like this. The Toloka control elements (such as the "send", "quit" buttons, etc.) cannot be changed, but you can modify the task interface.
I'm having a difficult time trying to understand how the control flow in protractor work in relation to how JS event loop works. Here is what I know so far:
Protractor control flow stores commands that return promises in a queue. The first command will be at the front of the queue and the last command will be at the back. No command will be executed until the command in front of it has its promise resolved.
JS event loop stores asynchronous task (callbacks to be specific). Callbacks are not executed until all functions in the stack have completed and the stack is empty. Before running each callback, there is a check on whether the stack is empty or not.
so lets take this code for example. The code is basically clicking a search button and a api request is made. Then after data is returned, it checks whether the field that stores the returned data exists.
elem('#searchButton').click(); //will execute a api call to retrieve data
browser.wait(ExpectedConditions.presenceOf(elem('#resultDataField'),3000));
expect(elem('#resultDataField').isPresent()).toBeTruthy();
So with this code, I'm able to get it to work. But I don't know how it does it. How is the event loop applied in this scenario?
The core of the ControlFlow implementation is in runEventLoop_ (in Selenium's promise.js implementation).
As I understand it, the ControlFlow registers a call to runEventLoop_ with the JS event loop (e.g., with a 0-second timeout or somesuch). The call to runEventLoop_ can be thought of as a single iteration of a normal event loop. It registers code to actually run a scheduled task (i.e., actually do the work you queued up during your it). Once that task completes or fails (e.g., by hooking its async promise callbacks) the next iteration of runEventLoop_ is scheduled (see the calls to scheduleEventLoop in runEventLoop_).
There is some complexity when a callback ends up registering new promises (those need to be "inserted" before the old next event, this is accomplished by creating a "nested" control flow. Mostly you should never have to know this.)
I need to add an Action to a Schedule object that is being created through the API. There are documented interfaces to set almost all the options except the Action. How are Actions attached to these Objects?
When I attempt to programmatically add a new event, read from a separate configuration file, to a Schedule object I get errors stating that the Schedule has already been initialized and that I must construct a new object and add its configuration manually. I can do most of that using the available Schedule API. I can set up everything about the Schedule except the Action code.
The Schedule is used in a Process Model. Looking at the model in the Java editor, I see the code I'm trying to replicate via the API in a function that looks like this:
#Override
#AnyLogicInternalCodegenAPI
public void executeActionOf( EventTimeout _e ) {
if ( _e == _fuelDeliverySchedule_Action_xjal ) {
Schedule<Integer> self = this.fuelDeliverySchedule;
Integer value = fuelDeliverySchedule.getValue();
logger.info("{} received {} pounds of fuel", this.getName(), this.fuelDeliverySchedule.getValue());
this.fuelAvailablePounds += fuelDeliverySchedule.getValue();
;
_fuelDeliverySchedule_Action_xjal.restartTo( fuelDeliverySchedule.getTimeOfNextValue() );
return;
}
super.executeActionOf( _e );
}
Maybe I can use something like this to create my own action function, but I'm not sure how to make the Scheduled event use it.
Thanks,
Thom
[Edited (expanded/rewrote) 03.11.2014 after more user detail on the context.]
You clarified the context with
When I attempt to programatically add "a thing that happens", read
from a separate configuration file, to a Schedule object I get errors
stating that the Schedule has already been initialized and that I must
construct a new object and add its configuration manually. I can do
most of that using the available Schedule API. I can set up everything
about the Schedule except the Action code.
(You might want to edit that into the question... In general, it's always good to explain the context for why you're trying to do the thing.)
I think I understand now. I presume that your config file contains scheduling details and, when you say you were trying to "add a thing that happens" (which errored), you meant that you were trying to change the scheduling 'pattern' in the Schedule. So your problem is that, since you couldn't adjust a pre-existing schedule, you had to instantiate (create) your own programmatically, but the Schedule API doesn't allow you to set the action code (as seen on the GUI schedule element).
This is a fairly involved solution so bear with me. I give a brief 'tl;dr'
summary before diving into the detail.
Summary
You can't programmatically code an AnyLogic action (for any element) because that would amount to
dynamically creating a Java class. Solving your problem requires recognising
that the schedule GUI element creates both a Schedule instance and a
timeout event (EventTimeout) instance to trigger the action. You can therefore create these two elements explicitly yourself (the former dynamically). The trick is to reset the timeout event when you replace the Schedule instance (to trigger at the next 'flip' point of the new Schedule).
[Actually, from your wording, I suspect that the action is always the same but, for generality, I show how you could handle it if your config file details might want to change the nature of the action as well as those of the scheduling pattern.]
Detail
The issue is that the GUI element (confusingly) isn't just a Schedule instance
in terms of the code it generates. There is one (with the same name as that of
the GUI element), which just contains the schedule 'pattern' and, as in the API,
has methods to determine when the next on/off period (for an on/off schedule) occurs. (So
it is kind of fancy calendar functionality.) But AnyLogic also generates a
timeout event to actually perform the action; if you look further in the code
generated, you'll see stuff similar to the below (assuming your GUI schedule is called
fuelSchedule, with Java comments added by
me):
// Definition of the timeout event
#AnyLogicInternalCodegenAPI
public EventTimeout _fuelSchedule_Action_xjal = new EventTimeout(this);
// First occurrence time of the event as the next schedule on/off change
// time
#Override
#AnyLogicInternalCodegenAPI
public double getFirstOccurrenceTime( EventTimeout _e ) {
if ( _e == _fuelSchedule_Action_xjal ) return fuelSchedule.getTimeOfValue() == time() ? time() : fuelSchedule.getTimeOfNextValue();
return super.getFirstOccurrenceTime( _e );
}
// After your user action code, the event is rescheduled for the next
// schedule on/off change time
_fuelSchedule_Action_xjal.restartTo( fuelSchedule.getTimeOfNextValue() );
i.e., this creates an event which triggers each time the schedule 'flips', and performs the action specified in the GUI schedule element.
So there is no action to change on the Schedule instance; it's actually related to the EventTimeout instance. However, you can't programmatically change it there (or create a new one dynamically) for the same reason that you can't change the action of any AnyLogic element:
this would effectively be programmatically
creating a Java class definition, which isn't possible without very specialised
Java code. (You can create Java source code in a string and
dynamically run a Java compiler on it to generate a class. However, this is very
'advanced' Java, has lots of potential pitfalls, and I would definitely not
recommend going that route. You would also have to be creating source for a user subclass
of EventTimeout, since you don't know the correct source code for AnyLogic's proprietary EventTimeout class, and this might change per release in any case.)
But you shouldn't need to: there should be a strict set of possible actions that your config file can contain. (They can't be arbitrary Java code snippets, since they have to 'fit in' with the simulation.) So you can do what you want by programmatically creating the Schedule but with a GUI-created timeout event that you adjust accordingly(assuming an off/on schedule here and that there is
only one schedule active at once; obviously tweak this skeleton to your needs
and I haven't completely tested this in AnyLogic):
1. Have an AnyLogic variable activeAction which specifies the current active
action. (I take this as an int here for simplicity, but it's better to use a
Java enum which is the same as an AnyLogic 7 Option List, and can just be
created in raw Java in AnyLogic 6.)
2. Create a variable in the GUI, say called fuelSchedule, of type Schedule but with initial value null. Create a separate timeout event, say called fuelScheduleTrigger, in User Control mode, with action as:
// Perform the appropriate action (dependent on activeAction)
doAppropriateScheduleAction();
// Set the event to retrigger at the next schedule on/off switch time
fuelScheduleTrigger.restartTo(fuelSchedule.getTimeOfNextValue());
(Being in User Control mode, this event isn't yet triggered to initially fire, which is what we want.)
3. Code a set of functions for each of the different action alternatives; let's say
there are only 2 (fuelAction1 and fuelAction2) here as an example. Code
doAppropriateScheduleAction as:
if (activeAction == 1) {
fuelAction1();
}
else if (activeAction == 2) {
fuelAction2();
}
4. In your code which reads the config file and gets updated schedule info.
(presumably run from a cyclic timeout event or similar), have this replace
fuelSchedule with a new instance with the revised schedule pattern (as you've
been doing), set activeAction appropriately, and then reset the timeout event to
the new fuelSchedule.getTimeOfValue() time:
[set up fuelSchedule and activeAction]
// Reset schedule action to match revised schedule
fuelScheduleTrigger.restartTo(fuelSchedule.getTimeOfNextValue());
I think this works OK in the edge case when the new Schedule had its next 'flip' at the time
you set it up. (If you restart an event to the current time, I think it schedules an event OK at the current time which will occur next if there are no other events also scheduled for the current time; actually, it will definitely occur next if you are using a LIFO simultaneous-time-scheduling regime---see my blog post.)
Alternative & AnyLogic Enhancement
An alternative is to create a 'full' schedule in the GUI with action as earlier. Your config file reading code can replace the underlying Schedule instance and then reset the internal AnyLogic-generated timeout event. However, this is less preferable because you are relying on an internally-named AnyLogic event (which might also change in future AnyLogic releases, breaking your code).
AnyLogic could help this situation by adding a method to the Schedule API that gets the related timeout event; e.g., getActionTriggeringEventTimeout(). Then you would be able to 'properly' restart it and the Schedule API would make much clearer that the Schedule was always associated with an EventTimeout that did the triggering for the action.
Of course, AnyLogic could also go further by changing Schedule to allow scheduling details to be changed dynamically (and internally handling the required updates to the timeout event if it continued to be designed like that), but that's a lot more work and there may be deeper technical reasons why they wanted the schedule pattern to be fixed once the Schedule is initialised.
Any AnyLogic support staff reading?
Is there any way to pause/resume a running workflow created using chains from celery 3.0?
Basically, we have two different types of tasks in our system: interactive and non-interactive ones. The non-interactive ones we have all the parameters for, but the interactive ones need user input. Note that for the interactive tasks, we can only ask for user input once all the previous taks in the chain have been completed, as their results will affect the interactive tasks (i.e. we cannot ask for user input before creating the actual chain).
Any suggestion on how to approach this? Really at a loss here..
Current ideas:
Create two subclasses of Task (from celery import Task). Add an extra instance (class member) variable to the Interactive task subclass that is set to false by default and represents that some user input is still needed. Somehow have access to the instance of the Task, and set it to true from outside the celery worker (Though I have looked this up quite a bit and it doesn't seem possible to have access to Task objects directly from another module)
Partition the chain into multiple chains delimited by Interactive jobs. Have some sort of mechanism outside the celery worker detect once a chain has reached it's end and trigger the interactive task's interactive client side component. Once the user has entered all this data, get the data, and start the new chain where the interactive task is at the head of the new chain.
We have implemented something like your second idea in our project & it works fine. Here is the gist of the implementation.
Add new field status to your model & override save method.
models.py:
class My_Model(models.Model):
# some fields
status = models.IntegerField(default=0)
def save(self, *args, **kwargs):
super(My_Model, self).save(*args, **kwargs)
from .functions import custom_func
custom_func(self.status)
tasks.py
#celery.task()
def non_interactive_task():
#do something.
#celery.task()
def interactive_task():
#do something.
functions.py
def custom_func(status):
#Change status after non interactive task is completed.
#Based on status, start interactive task.
Pass status variable to template which is useful for displaying UI element for user to enter information. When user enter required info, change the status. This calls custom_func which triggers your interactive_task.
I have googled around and think I have tried just about every suggestion I've seen but I can't seem to get this to work the way I want to. I'm CONVINCED that SSIS can do this.
I have an SSIS package that has 4 tasks, they execute in order: task A, then B, then C. The 4th task D I am using as an end-point if B fails... more on that in a minute.
Task A does some unrelated work. I'm including it because there's processing at the start of the package and should any of it fail, then I want the package to fail - just the SSIS default, exit the package with a return code of 1 if task A fails.
B is a DFT with a flat-file source, it transfers data to be processed in step C. B is the crux of my question because I want to deal with errors in task B differently than the rest. It's not uncommon for the flat-file source to not exist or to be corrupt and I want to capture/trap that but not cause the entire package to fail. If B does have an error though, I do NOT want to process task C.
C processes the data I transferred in DFT B when B does not have an error.
I am trapping errors in DFT-B with an "OnError" eventhandler that executes a SQL task that sends an email. I then use an "on completion" precidence constraint to divert the control flow to an endpoint - task D. (D does nothing, it's just a dummy end-point that I'm using partially for debugging, partially to give the event handler somewhere to "go" - I am not certain D is even required).
Anyway, when I run the package and trigger an error in B my package performs the event handler (sends the email just fine), it even continues on to task "D", and in the debugger, "D" ends with success (shows green). The problem is, my package fails with an exit code of "1".
I've tried messing with all sorts of things... ForceExecutionValue/ ForceExecutionResult/ MaximumErrorcount. Now I have a package that actually doesn't even contiune to my "task D" and I'm not sure how I got there (but the exception handler SQL is faithfully sending me an email!).
I do not want that exit code of 1! I want a 0!
help! thanks!
Have you tried something like this:
To get the different conditions on the transition lines, just double click on the line you wish to edit. A red line indicates the control flow in case the previous task fails
EDIT: I believe i misread the question! From what i got, you can already control the flow as intended. Your issue comes with the exit code. Have you tried setting the propagate variable to false in the event handler screen?
Check the following link for more information on it:
http://simonworth.wordpress.com/2009/11/11/ssis-event-handler-variables-propagate/