We are evaluating and looking for a workflow engine which support .NET-Core and I'd really appreciate the community input. I would like to hear on the suggestion based on your guys implementation stories.
My main evaluation criteria, so far, are below;
open source and OEM friendly license
production installations (success stories are a great help)
technical support available
open standards support - BPMN
dynamic creation/assembly of the workflow based on input
embeddable
Currently I am evaluating Elsa, Workflow Core, Argo, and Airflow. Elsa seems like a good candidate as well but never used it.
Do you guys have any successful deployments on Elsa workflow engine?
Full disclosure: I am the project lead of Elsa, but I will try and be as objective as I can.
Elsa does not currently support BPMN, so if this is a hard requirement then Elsa might not be suitable for your project. At least not until it implements BPMN in the future.
As for technical support, there is no official paid support available as of yet, but the community is very friendly & helpful, though still relatively small.
Dynamic creation based on input is possible since you can programmatically define workflows. But you cannot update workflows while it executes (which would be more or less similar to being able to update your C# program statements as your program runs). Not sure if this is what you are looking for or not?
Other than that, Elsa is OEM friendly, runs in production successfully at several companies that I know of and is embeddable.
Is there any tool to convert existing JavaFX 1.x applications to JavaFX 2.x Java code?
No such tool currently exists publicly and it is unlikely that one will be created.
Oracle did create a prototype tool which was used in internal Oracle development, but they decided not to continue development on it.
Quotes from the JavaFX project lead Richard Bair (from the forum threads linked below):
Richard: I'm sorry to say we have no tool to help with the migration. Our
experience from migrating the JavaFX Library and samples is that there
wasn't really an easy solution -- even the migration assistant that
was written was very incomplete. Some folks found it very useful, but
I just did it by hand.
PDVieira: Any chance you could send me the FxTranslator helper you've
created?
Richard: Wish I could, but unfortunately we cannot send it along
(actually, I don't even have the code on hand, didn't write it (Eamonn
did) and it would need to get legal approve to open source it, and it
probably doesn't even compile or work anymore because the platform has
change significantly since last December).
You can refer to these forum threads which discuss this further:
https://forums.oracle.com/forums/thread.jspa?messageID=9967190
https://forums.oracle.com/forums/thread.jspa?messageID=10064115
I want to use Asio and Qt together ? each of them have a two method that must be called and each of them are blocking for example : Asio has io_service.run() and qt has QCoreApplication.exec() if I run one of them then another cannot be run.
I have two solutions:
create another thread and call io_service.run() from that.
create a timer with 100ms cycle and call io_service.poll() from same thread that call QCoreApplication.exec().
These solutions are correct?
This is simple solution and works on every platform, but it has some minor drawback. You are introducing latency to asio-part of your application, which may be acceptable or not - depends on your case.
You may be interested in my solution, that makes real integration of asio and QT mainloops.
Look also at the following question for more on this topic: How to integrate Boost.Asio main loop in GUI framework like Qt4 or GTK
You definitely want to look into multi-threading your application. Qt helps you out with pretty good platform-independent threading classes. You'll also need to address communication between objects owned by different threads and also will need to bear in mind that painting is limited outside of the GUI thread.
Currently i am working on developing one Warehouse solution from scratch, i am planning to build it in silverlight (as this solution will take around 8-10 months) and the programming will start from Feb 2010.
I need to develop this application for one organization. Certain parts needs to be accessed by public which we are planning to build in ASP .Net 3.5
Now i just wanted to start a thread here for pros and cons of using silverlight, some of them i have already analyzed
Pros :
Rich UI
Excellent user experience
Reduction of scalability concerns
New set of features like data binding, control template etc..
Speed of development (After initial learning curve..my experience says it is faster to develop it in silverlight)
Other rich set of features coming up with SL 4.0 (SL 4.0)
Cons :
Cross platform issues (moonlight is there but it may take some time)
Cross browser issues (Chrome or other browsers)
Learning curve
Any other unknown risk (As there are not many enterprise level application developed in silverlight...or may be i am not aware)
I have also got one link for Pros and cons of silverlight(here) some of the cons might not be relevant with SL 4.0
Also i am having one good link for comparison between ASP .Net Ajax with Silverlight (here)
EDIT :
I have also found Technical Article series in code project (Just Type # google "Adventures while building a Silverlight Enterprise application" and you will get it, i am trying to analyze this series as well)
Please add some pros and cons if you find as i am trying to analyze it from all the angles. It will be of great help if you find any whitepaper on it.
The Pros and Cons have to be weighed against your own requirements.
Rich UI
Compared to what? Its not really a Pro, other tools can deliver Rich UI, where does one draw the line that allows a UI to call itself Rich? A Pro can't be a Pro if can't be measured.
Excellent User Experience
That isn't a Pro either. I wish I could buy product that delvers such a thing out of the box. The reality is it's up to you to deliver the UX. E.g. Stackoverflow delivers an excellent user experience, it doesn't use a tool like SL and it's entirely down to good design not the tool (ASP.NET-MVC+various other tools).
Reduction of Scalability Concerns
Compared to what? Early ASP.NET Forms with extensive use of callbacks then yes. However plain old HTML with Javascript frameworks can deliver this same "Pro".
Speed of Development
Well that depends on how you measure speed and how you weigh the importance of the UX. Currently SL developement isn't any better at ticking off business function points than other tech like poor old ASP.NET Forms and is probably worse. However delivering those same function points with a slick, imaginative UI may tip the balance more in WPF/SL's way. In reality SL allows you deliver more UX with some (but importantly not prohibative) extra effort.
Other Rich Features in SL4
Only a Pro if they would actually add value to your requirement.
Cross Platform
Do you really have a Cross Platform requirement? Within a warehouse business how many Linux and Mac desktops are there? That should answer your cross platform question.
Cross Browser
Is this a Con? Does the company in question allow the use of a variety of browsers? If so which? You can compare that to the browsers SL4 supports and out pops your answer but its your answer not everyones answer. Isn't cross-browser a bigger concern for the Extranet-esq part of the app?
Learning Curve
In all of these factors what are you already versed in is by far and away the most important. I'm guessing its MS tools and in particular .NET, right?
If you're not familiar with WPF already there is some learning curve but its not very steep. However you should definitely make sure you take the time to perform some training projects before you even start designing your real product. That process should help you measure how long it will really take and whether it is really feasable.
Other Known Risks
SL is still very young and it won't sit still. Frustrating "issues" will eat time.
Other questions to ponder
What UX ideas do you have that can't be delivered by a browser?
Why deliver the app via a browser hosted app at all? A WPF application not an option?
Silverlight 4
Considering your timescales if you do choose Silverlight you should target SL4.
Since you are developing solution for the warehouse, you may need consider building a web service with wcf pollDuplex (basically push data from server to the client periodically), just a note on it: it is not (yet) a very scalable and reliable (prior to SL4). Default concurrent connection is 10 (if I remember well), and you have the option to overwrite this default number, however, I haven't find a way to dynamically change this number which turns out to be a scalability issue.
One cool feature I like about SL 4 is the added support of printing, now you have the built-in ability to print the content.
Anyone bulding an Enterprise LOB with a Silverlight client should take a look at John Papa's PDC video.
However, IMHO the initial release of RIA Services was too limited. Now that the next version is buit on top of WCF Services, and the endpoints can be switched out to make them more accessible by more UI clients RIA Service is probably a very sensible investment too.
I am evaluating WF for use in line of business applications on the web, and I would love to hear some recent first-hand accounts of this technology.
My main interest here is in improving the maintainability of projects and maybe in increasing developer productivity when working on complex processes that change frequently.
I really like the idea of WF, however it seems to be relatively unknown and many older comments I've come across mention that it's overwhelmingly complex once you get into it.
If it's overdesigned to the point that it's unusable (or a bad tradeoff) for a small to medium-sized project, that's something that I need to know.
Of course, it has been out since late 2006, so perhaps it has matured. If that's the case, that's another piece of information that would be very helpful!
Thanks in advance!
Windows Workflow Foundation is a very capable product but still very much in its 1st version :-(
The main reasons for use include:
Visually modeling business requirements.
Separating your business logic from the business rules and externalizing rules as XML files.
Separating your business flow from your application by externalizing your workflows as XML files.
Creating long running processes with the automatic ability to react if nothing has happened for some extended period of time. For example an invoice not being paid.
Automatic persistence of long running workflows to keep resource usage down and allow a process and/or machine to restart.
Automatic tracking of workflows helping with business requirements.
WF comes as a library/framework so most of the time you need to write the host that instantiates the WF runtime. That said, using WCF hosted in IIS is a viable solution and saves a lot of work. However the WCF/WF coupling is less than perfect and needs some serious work. See here http://msmvps.com/blogs/theproblemsolver/archive/2008/08/06/using-a-transactionscopeactivity-with-a-wcf-receiveactivity.aspx for more details. Expect quite a few changes/enhancements in the next version.
WF (and WCF) are pretty central to a lot of the new stuff coming out of Microsoft. You can expect some interesting announcements during the PDC.
BTW keeping multiple versions of a workflow running takes a bit of work but that is mostly standard .NET. I just did a series of blog posts on the subject starting here: http://msmvps.com/blogs/theproblemsolver/archive/2008/09/10/versioning-long-running-workfows.aspx
About visually modeling business requirements.
In theory, this works quite well with a separation of intent and implementation. However, in practice, you will drop quite a few extra activities on a workflow purely for technical reasons, and that sort of defeats the purpose as You have to tell a business analyst to ignore half the shapes and lines.
Related question: When to use Windows Workflow Foundation? My answer there:
You may need WF only if any of the
following is true:
You have a long-running process.
You have a process that changes frequently.
You want a visual model of the process.
For more details, see Paul Andrew's
post: What to use Windows Workflow Foundation for?
Please do not confuse or relate WF
with visual programming of any kind.
It is wrong and can lead to very bad
architecture/design decisions.
So, if you have such requirements, then WF is a good candidate. Of course it is relatively complex, but mention that the problems that is trying to solve is also complex (and sometimes very complex). IMHO, it is very complex for example to dehydrate/rehydrate objects that have event handlers attached (with events that can be triggered when the object is not in memory).
I can not judge what you mean by "small to medium-sized project", but in general I would say that if your project has at least two requirements from the above list, then you can consider WF as a solution.
We've used WF in a large-ish SharePoint application and I can say it's OK. It has lots of power and flexibility. and, as Kevin mentions, once you grok the underlying concepts of workflows, you can do pretty much anything you want with it.
On the other hand, it has some really serious issues, like lack of versioning, which can really hurt your application in the future. We've been forced to deploy up to 3 parallel versions of the same workflow named xxx-v1, xxx-v2 and xxx-v3 to keep older instances running and have new instances use the updated versions. A real pain in the ass. Oh, and there are also some really non-intuitive concepts in there (correlation tokens, wtf??)
We had a project at work that I was involved in using Workflows.
The idea (from management), was that us programmers would write the Workflow Activities along with the "engine" and framework. Then non-programmers would take care of all the rest by compiling their own Workflows into dlls which the engine would automatically load.
Management was sold on this idea of non-programmers using Workflow to help develop software, and it was pretty much a complete waste of time. The problem we were trying to solve with this project was relatively complex and we knew from the very beginning that the software would have to be modified almost constantly (its calculations were dependent on other companies and governements).
The end result was that we were unable to make the Workflow modules generic enough for anyone else to use. So the programmers were the ones who were forced to work with the Workflows, and all the Workflows did was get in our way.
I've been using Workflow 4.0 for the last few months and although mostly impressed, I've found it extremely hard to learn.
For the most recent version (that comes with .NET 4.0 RC), there is next-to-no documentation on the web, in any books or no training courses available. I've only found articles relating to the now defunct 3.0 version. Even the MSDN documenation is light on the ground.
The workflow designer is not as intuitive as it should be by any means so learning is very hard. I've had to rely on answers from a single person on StackOverflow (thanks by the way Maurice!) - and I would be stuffed without his help.
So in summary, I think it has potential but you would be quite mad to learn it yet - wait for more training, documentation and books otherwise you will be going into it blind!
Last year we completed a working application with WF, now used as the backbone of an unbelievably huge system which is used by a very big bank for its mortgage process. The pe process has many steps starting from customer application to approval of credit.
Although it was a success, there were so many problems and crisis all along the way. And it wont worth the trouble for any smaller size projects.
I consider MS WF as a low-level workflow library rather than a fully fledged enterprise workflow product such as K2. It will enable you to build a workflow enabled application, but is not in itself a workflow application. My experiance of it in this capacity has been positive, although we have had to build a lot of our own infrastructure around it (a pub/sub framework, a worlkflow lifetime manager etc). A lot of the documentation out there is fairly simplistic and does not cover building up an enterprise workflow application based on MS WF.
Hard to learn. Quite flexible. Not to be confused with a visual tool for end users, only for programmers. Not sure if I like the dependancy property approach.
It really depends on what you want to do with it. I've only used it a little, but compared to more mature products like MetaStorm (I know technically it's a BPM, but there is still a workflow component), Process Choriographer and IBM MQ workflow, there's no comparison. It's just not mature enough. On the other hand it's free where the others are not and can probably get the job done. I don't know if I would place a multi-million dollar operation on it, but with smaller ones, I'd give it another shot. The real hurdle you are going to face is the change in thought process it requires. If you don't have developers that have worked with state systems before that can be a real hurdle.
Brian, I can't reply to your comment, but anyway, by versioning i mean making changes to the underlying code of the workflow without breaking already running instances, and gracefully applying updates to existing workflows. I'm not sure about 'stock' WF, but at least in SharePoint environment there's no concept of workflow versions so new versions have to be deployed as completely different workflows which becomes a maintenance nightmare.
This has nothing to do with 'rehydration', rehydration is the process by which you bring a 'dormant' workflow back to activity after some event or change in state. That is handled transparently by the workflow runtime.
WF ist integrated into SharePoint (WSS 3.0), and i have created quite a few workflows for various SharePoint-Websites, so i can tell about my experience of WF in SharePoint. Compared with other workflow-frameworks WF scores well. It's stable (i haven't experienced any mysterious errors), workflows are fairly easy to design (thank to the workflow-designer in Visual Studio) and you can use not only sequential but also state-machine workflows.
It's not perfect, of course, and a developer will definitly need some time to understand the concept (of i.e. the Activity Model); but it's definitely useable - even for "small tasks".
Never tried WFF, but I remember reading this article about WFF by Leon Bambrick where he basically says the whole genre of software development tools is nonsense. Might help you decide one way or the other.