I have read the handbook for Pega PRPC 6.3, How can I create subflows within the main flow? Is there any resource/tutorial that shows a step by step approach?
Also I need to add steps and parameters for a flow, how shall I do that?
Subflows are just normal flows. You can call them from your main flow by dragging a subflow shape to your flow diagram and refer the flow you want to make as subflow.
You can visit https://pdn.pega.com for more information and resources.
To add steps to your flow, you can easily drag and drop items from the menu. To add a parameter, go to parameters tab and add your parameter name type and other info. You can pass the value for the parameter when you call the flow.
Related
As part of our product requirements, we need to support a dynamic workflow configuration that will be set by the product's administrations.
Below is an example from Monday's system of this concept.
Meaning that the user can define the custom flow of event --> conditions / branches --> actions that will set the workflow.
Need to support events that are based on schedule and also on system configurations changes (an object changed it's state)
What is the best way to implement this on the back-end side? what module/tool should be used in order to execute the workflows?
We thought of the following design:
Create a workflow object for the whole workflow tree saving it as a hierarchical JSON object that contains the defined user hierarchy of the different objects (event, conditions, actions) and storing it in the database.
Use Apache Workflow as an orchestrator and create DAG dynamically based on the defined workflows and update them accordingly.
Is there a better tool to implement the following design? (saw some posts relating to this, but with no answer: 1, 2)
Thanks!
I want to build Elsa workflow for the below requirement:
Can be trigger from database table trigger when new row inserted.
Can execute exe file to get some information.
To read data from the database.
I agree with #fatihyildizhan and #vahidnaderi, but if I interpret the question as "How to do these 3 steps with Elsa from a high-level overview - can someone give me any pointers?" then I can answer as follows:
If all you really need are the 3 steps you mentioned, then don't use Elsa; it is overkill for what you want to do.
Here's why:
Although you can achieve all of this with Elsa, you can't do it with Elsa out of the box; you will have to write custom activities and support services to trigger your workflows, which is a little bit more work than simply doing your thing from your "row inserted" application handler.
If, on the other hand, you are planning on implementing multiple workflows that are potentially more complicated and perhaps even long-running, then it might be worthwhile to consider Elsa after all.
Doing this with Elsa requires you the following up-front work:
1. Trigger Workflow When New Row Inserted
To trigger a workflow when a new row is inserted, you need to implement a handler that responds to that event (this you would need to do regardless of whether you use Elsa or not).
Next, you need to implement a custom activity that represents the "row inserted" event as a trigger, e.g. called RowInserted. You can then use that activity as a starting point in any of your workflows or even as a resumption point (e.g. for workflows where you began some work that might insert some eventual addition of a database row, which is the event you want to handle), which would be triggered whenever a new row is inserted. You probably want to be able to configure for which database table to trigger this event, so you might add a TableName property to your activity.
Then, in order to make Elsa actually trigger workflows with your custom activity, you will need to do the following:
Implement a bookmark model and provider for Elsa to index and invoke. E.g.
NewRowBookmark : IBookmark with a single property called TableName. Bookmarks are Elsa's way of starting & resuming workflows.
Update your "row inserted" handler described earlier to invoke IWorkflowLaunchpad.CollectAndDispatchWorkflowsAsync, passing in the appropriate bookmark/trigger model containing the table name into which the row was inserted, and provide the inserted row as input (assuming you want the workflow to do something with the inserted row).
2. Execute File
To execute a file, you need to create another custom activity that does this. You can make this activity as specific or generic as you need.
3. Read From Database
Same as with #2, you need to create another custom activity that reads from the database. You can make this activity as specific or generic as you need.
The above should give you a rough idea of the work involved to implement this with Elsa. And as mentioned earlier, this might be overkill if all you are looking to do is do the 3 steps mentioned.
Why(In what scenarios) do we need to integrate Spring Webflow with Spring MVC? Both these frameworks are used to create web-app and I do not see any point why we would integrate them. I would appreciate if someone could clarify me about it.
This is really late but I don't see a satisfactory answer to this question and would like to share an approach I had tried in a recent project which I feel is better than the spring web flow approach which is strictly tied down to spring views and unnecessarily adds to the already existing xml load . I created a SPA(Single Page Application) using angular js with Spring MVC. In angular js I did not use routers or state, rather I created a div within the controller like below
On the server side to capture all possible transitions from one frame(I am referring to a particular screen in the SPA) to another I created a tree of rules using MVEL . So in the database I had a structure which stored a tree of rules for every frame . The data in the MVEL expressions were being set by the various services each action invoked. Thus on any action the following steps were followed.
1) Validate the action.
2) Invoke various services.
3) Capture the data from these services and merge it with the existing data of the user.
4) Feed this captured data into collection of rules for each frame along with the details of the current frame.
5) Run the rules of the tree w.r.t to current frame and fetch its output.
6) If there is only one transition then that is the final transition. If there are 2 transitions and one is default then ignore the default transition and use the other transition.
7) Return the template name of the transition to the angular controller and set the value of the page variable in the scope of the controller.
Using this approach all my services had to do was store data in different data fields w.r.t a particular action. All the complex if-else conditions for Web Flows or any complex process definitions(like the one defined in Spring-Web Flow) were not required. The MVEL rule engine managed all that and since it was all in the database it could be changed without needing a server re-start.
I believe this generic approach with MVEL is a flexible approach which comprehensively handles the problem of a convoluted flow without making the application code a mess or adding additional unnecessary xml files.
We combine both. Web Flow for the multi-step activities, where it doesn't make sense to jump into the middle of a process, and plain-MVC Controllers for the single-step activities. Things you might bookmark individually.
For example, an appointment-scheduling application, "find my appointment" might be a single Controller that accepts identifying information. "Make a new appointment" is a flow, with multiple steps of selecting a location, date, time, confirm the appointment, etc.
If your application have complex Flow pages, events which need to be defined as Finite state machine then use Webflow. It would be justified to use webflow for website where you buy Insurance, Flight Tickets. Web Flow conditions are like:
There is a clear start and an end point.
The user must go through a set of screens in a specific order.
The changes are not finalized until the last step.
Once complete it shouldn't be possible to repeat a transaction accidentally
I am learning pureMVC and trying to implement the framework into one of my application. I have follwing case:
My main application has Canvas which is used to add different kind of custom components. One of the custom component is a "Search Component" (multiple instances are created on page). My search component has a textfiled and a search button and initiate search in following steps:
1-Clicking search button dispatches a custom event, that custom event keeps reference of search component as a property.
2-My AppMediator listens the custom event and get the reference of current search component along with search text.
3-Mediator send a notification (sentNotification(AppConstants.SEARCH_CLICKED, component)).
4-I have registered a command with SEARCH_CLICKED notification.
5-Command retrieve a WebserviceProxy and invokes its Search(text) method.
6-WebserviceProxy talks to remote webservice and uses asyncToken to get results.
My Questions is:
My Command has the reference to the custom search component when it start search but search webservice takes some time and get the result. How can i handle the results back to custom search component that initiated the search. Since i have multiple instances of search component. What is the best place to keep the reference of that component, should i add a variables in WebserviceProxy to keep that reference and hand the results over to it, or i have to create a Global Proxy to keep references of such components?
Thanks
I have been using PureMVC for some years and I like it!
I think you have not yet understood roles and collaboration of main components.
You should not have any dependencies between Commands and UI-elements. Your Mediator has to get the concrete value from your UI-component and send it through the Notification. In this case the Command and the Proxy will get only a text value and it is no matter, what is the source of it! Suppose you will change your UI after some time and you will have another components on the user side to determine the search value. In your case you would have to change the Proxy and the Command. It would be bad.
Proxy may not have any information about Commands and Mediators. It can only offer its functions to let another components interact with it AND it sends Notifications with new information after getting it without knowing who is interesting in it.
Read the description of the framework once more and write your questions.
I had some problems with understanding the stuff too, I see your problem.
Based on Anton's answer, i re-think and tried to separate dependencis. As a result, i tried to mediate each instance of Search Widget with "SearchMediator" separately by providing different ID to the constructor of Mediator. Now, when search widget intiates a new search, it's mediator invokes the Command, Command invokes a method of Proxy to do actual search and fetch results from DB and sends a Notification. SearchMediator takes care about that notification and hands over the results to appropriate UI.
I'm working on a huge project and we would like to have a different management of continuation for some flows.
We want to be able to use the continuation snapshots (those that permit the use of the back button) for most of our flows but we also want to be able to totally disable continuation snapshots for some of our flows that use huge quantity of memory and that we don't want to serialize.
Is it possible ? And how ?
Thank you very much.
Big caveat that I haven't tried to do any of this. But, here's a potential approach.
First of all, you need your own implementation of FlowExecutionSnapshotFactory. This will allow you to manage the creation and restoration of snapshots. You'll probably want to wrap SerializedFlowExecutionSnapshotFactory, but only allow the snapshot to be created in certain circumstances. Even better, you might want to allow the snapshot to be created, but to omit some of the data from it.
Now the problem is getting Webflow to use your new SnapshotFactory. The factory is created in FlowExecutorFactoryBean.createFlowExecutionSnapshotFactory(). So you need to get this created. You can specify your own FlowExecutorFactoryBean in your application-context.xml file. There's instructions on how to do that at http://forum.springsource.org/showthread.php?54714-SWF-2-0-Backtracking-and-exception-catching - scroll down to angrysoul's post at the bottom.
Now you just need to make sure you provide your own own instance of FlowExecutorImpl, that contains your own snapshot factory.