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Hello.
First, let me introduce myself:
I am a Java (6 years exp), Python(2 years exp), and C (2 years exp) developer.
This thread is both a question for all programmers (feel free to reply!) and a little bit informative for some 
So, I have been working on a relatively complex system (link[^]) that does the following:
a- (OpenCV) reads frame by frame and detect motion, from a webcam
b- reads from a second webcam without processing, just to watch
c- controls a parallel port or usb device
d- generates custom simple sounds
e- logs everything described here.
f- has a Graphic User Interface to control all of the above parameters.
So 2 webcams, audio out, usb device, and graphic user interface, is in short what this system has.
I've done this in python and it took me some 10k lines of code and weeks/months of time. So far works with some random errors, and a below-decent (in my opinion) interface.
I wanted to ask this community if Java might be a better language at accomplishing this task, which is my hypothesis, but would like a second opinion or your general opinion about this:
1- OpenCV
2- Generating audio
3- Controlling a USB device
4- multithreading
5- GUI
-------
I don't want to bias your opinion, but so far here is what i currently believe based on my work and exp programming on both languages:
1- OpenCV: Probably the same in both languages. Maybe Java is easier/more mature but IDK
2- Audio: Probably the same (someone might have done an audio class before)
3- Low level peripherals: I don't know. Probably Java has a disadvantage here?
4- Java's multithreading and multiprocessing seems to be far superior. Here's why:
. When you launch threads in Java, the JVM will allocate it on a free processor if available. If you have 8 processors and you launch 8 threads, ideally it will allocate one in each.
. While in Python , multithreading will use the same process for all threads. I managed to work around this by using multiprocessing [^] and what i gained was to make use of quad core and some better stability (OpenCV would complain with TKinter running at the same time, stability issues if using just one process, believe me).
. In Java, launching many threads will continue letting you use all variables in the "main program" ; it might be bad practice but it will let you anyway
. In Python, the main program must open joblists and pipes to send / receive information from the (many) modules and processes running simultaneously. This bloated my original code a lot (classes that had 200 lines before, now have 300 or more to handle jobs and queues, etc) , but was absolutely necessary because using just one process wouldn't have worked (i tried).
5- GUI:
. Java: i would have used JFrame, JPanel, and all that Swing package, which would look nice and behave properly
. Python: I used Tkinter AND also Glade GTK
I used both because Tkinter comes by default with Python but looks horribly (and behaves somewhat bad when interacting with so many processes . "Segmentation fault"  ).
So i introduced a second GUI: Glade GTK. Which looks good and behaves better than TK but it needs additional packages installed.
I'm in no way ranting; i even almost finished my Python code, but i am just wondering if i have done it in Java would have been better ?
So what would you use? Python ? Java? Any other language?
Sorry for the long post! cheers !
Just a programmer.
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For a desktop based UI, I would use C# and WPF. You can drop to low level code with it if you need to. It plays well with things like OpenCV and it is a powerful way to build custom UIs. The downside is that it's complex to learn.
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I have a table called Lookups. It's used mainly to populate ComboBoxes. There's a button next to it that opens an editor where the user can add, edit, and remove lookups. The table has a column called "LokupType".
Say for example the user enters 3 lookups called "Employee Type" and they are "Manager", "Driver", and "Dispatcher". The Employee screen has an Employee Type combo and editor button. and for employees the LookupType is "empytype", and that is hardcoded in the editor button's click routine. I can hard code it here because the code is in the Employee Screen.
In the Employee screen the employee is assigned a type from a combo loaded by a query that uses the LookupCode of "emptype". In other words, there's a query that returns only employee type lookup items.
So far so good.
Now here's the problem... In another screen I need to populate a list of only those employees who are Dispatchers.
Because the lookups can be removed, how can I know for sure which employees are Dispatchers?
In the past I used another column called SystemCode, and I would hard code in values such as:
LOOKUPTYPE CAPTION SYSTEMCODE
=========================================
emptype Manager empmanager
emptype Driver empdriver
emptype Dispatcher empdispatch
Because I had the system code, I could pull only those employees who are dispatchers. Now, the requirements call for ALL lookups to be editable and removable.... so there's no SystemCode.
I'm open to suggestion.
If it's not broken, fix it until it is
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There's currently a small internal debate over what language we should be writing an email polling service.
It is a part of a much broader system. Various accounts will be set up, and emails will be pulled from them and then encrypted and stored in a database.
As it is part of a larger system we are planning on using an ORM such as Entity Framework and have a DAL or C# API to handle all things database. C# .NET has a solid networking API and some mail related stuff already, as well as solid encryption.
Concerns surrounding using C++ include;
- Having to write network code from scratch (limited on external library use)
- Can not use Entity Framework or the C# database API, would require database code to be repeated in 2 languages allowing for transfer of bugs, more time taken etc..
- Encryption.. The clients are going to be .NET and so we want to use .NET encryption from start to finish so that encryption is standardized throughout
- Later in the projects life we want to support more than just Pop3 and IMAP, Microsoft provide a managed API for it's exchange web services. To achieve this in C++ is not elegant and not recommended by Microsoft
What are the advantages of using C++ in this scenario if any?
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Given all the reasons you have listed for not using C++, why are you even considering it?
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The reason it's being considered is because one senior developer is adamant it needs to be in C++. the rest of the team is set on C# however, he can't put together a coherent argument for C++ other than memory management and I'm trying to assess the situation.
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Given that he's the one who's adamant that it should be C++, why are you looking for reasons? If he cannot articulate a coherent argument in favour, he deserves to lose here.
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Member 8456971 wrote: he can't put together a coherent argument for C++ other than memory management
But C++ does not provide memory management, other than allowing you to consume as much as you want. If you do not win this argument then there is something seriously wrong with the management of your company.
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I would like to a continuous discussion about my question posted here:
How do I load a UI based on a user specific role[^]
and as was suggested I post a question here.
I am now currently reading suggestions on the answer posted on that question. If in any case you also have other sources please feel free to tell me
Thanks in advance 
-----
Update:
I would prefer using winforms on this project for im more comfortable with it. I usally develop using VS2012 with MSSQL2008r2 for my database. (I havent had the chance to upgrade yet).
And here's the complete content of the link (as suggested):
"This is just an educational query wherein I am trying to accomplish an application that loads a specific UI (after login screen) depending on a role assigned to a user.
I just need materials to study and read on, I have been searching google and I found this article so far
PluginManager - A C# utility to load plug-in based components[^]
Its almost close to what I am trying to study and accomplish, only that it does not full describe how the plugin is created and how to create the plugin manager.
As I said I am trying to accomplish an application that loads specific user interface depending on a role assigned to a user. The reason behind is that each user of the app has a totally different job than the other, its more like a permission based app not just for security but also for a good UI design specific to a role.
So I am only asking for references regarding such matter, any article or code samples will be very useful. I am still looking for sources and other samples, but I think getting a more personal suggestions would be best. "
modified 29-Jan-15 20:36pm.
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PhyxeTernida wrote: I would like to a continuous discussion about my question posted here:
Why?
If you want to load something at runtime, that would be a question. Why does it have to be a discussion? And what have you tried?
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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it would be a discussion for as i read your comments i might have additional questions about this topic. also it does not have to be on run time perse at the moment i have multiple projects (and they are ready for deployment) having the UI that i need to load depending on a user role. my ultimate goal would be to place all of those little projects i made to a single app and load the needed UI after the user with a specified role log in.
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PhyxeTernida wrote: my ultimate goal would be to place all of those little projects i made to a single app and load the needed UI after the user with a specified role log in.
So what is your actual question?
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im very sorry if om not that clear, my question would be: How am I going to accomplish that? Also I wanna know how the process work and if its possible with C# VS2012, so I am also asking for sample projects and references where I can learn as much as I can on doing such thing.
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PhyxeTernida wrote: How am I going to accomplish that?
By designing and writing some code.
PhyxeTernida wrote: I wanna know how the process work
Not sure what process you are referring to.
PhyxeTernida wrote: if its possible with C#
Most likely yes.
If you are looking for sample projects then you should go to the Articles section[^] and search there. When you have a specific question then come back here and people will try to help you.
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PhyxeTernida wrote: so I am also asking for sample projects and references where I can learn as much as I can on doing such thing.
You'd be asking other things, like "how do I check whether someone is in a specific role".
Start with small things. There won't be a forumpost explaining how to do a complete project.
Bastard Programmer from Hell 
If you can't read my code, try converting it here[^]
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You may get more/better responses to this question, here, if you include the complete text of your message on QA, and indicate which technology stack in .NET you are planning to use to implement this: WinForms ? WPF ? ASP.NET ?
Also, I suggest you take a look at Managed Extensibility Framework (MEF) [^] which is a relatively new facility from Microsoft specifically for managing/implementing plug-ins, etc.
«I'm asked why doesn't C# implement feature X all the time. The answer's always the same: because no one ever designed, specified, implemented, tested, documented, shipped that feature. All six of those things are necessary to make a feature happen. They all cost huge amounts of time, effort and money.» Eric Lippert, Microsoft, 2009
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Why does it need to be a plug in at all. You have to build the specific UIs so put them all in the same app and after login where you will get the role of the user you decide which UI to display.
We have a similar environment except a user may have multiple roles and functions within that role across multiple applications, web, desktop and mobile platforms. We cannot use AD groups as the response time (from the AD team) is abysmally slow.
We have built a single logon application that picks up the users credentials and passes the object to the client application on start up. Each application may have multiple roles dictating different views, this is built by the individual developer using the details from the credential object.
User credentials are maintained in another app by OUR user team, when you have 20+ applications and 1000s of users it gets a little unwieldy  .
Never underestimate the power of human stupidity
RAH
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Now that we know this will be a Windows Forms based project: some specific ideas based on WinForms' facilities:
Assumptions:
1. you will use standard system-services to handle the security aspects of verification of log-in of users, meaning: you will use Windows' Groups/Roles/Permissions facilities and encrypted log-in information stored in your database.
Ideas:
1. Log-in Application: one Windows Form, UserName, Password, Text Fields, LogIn Button, Exit Button.
a. stand-alone project, contains no other Form definitions, no hard-coded filepaths to the location of the users' interfaces ... Forms (Admin, Manager, User ... etc.).
2. UserFormLocator Service: receives a request from the Log-in app for a path to a valid folder containing the .dll with the user-interface appropriate to the logged-in User, and returns the filePath to the LogIn app after a valid log-on.
3. Forms for different types of Users ... for example, Admin, Manager, User1 ... these can, of course, all use a common base host interface. For example, you could have one main Form with certain common features defined in a .dll, then have a separate .dll containing a Panel with all the specific Controls for each type of user. At run-time the common Form can be loaded, and then the specific Panel loaded and inserted into the common Form's Controls collection.
4. After a valid log-in, the Log-in Application uses the filepath to the .dll returned by the Service to Load and instantiate the particular user interface for a given type of User. The Log-In Application closes its own UI and transfers the message loop to the newly instantiated user-interface (Form).
Technical Note on 4.:
This requires use of an explicit ApplicationContext in WinForms: rather than starting the Application with the usual command to "Run" a Form, the Application is started by launching the instance of an ApplicationContext: this allows one to close any given Form and open any other Form. This also requires some caution since the Application can still be running with no open Forms: typically the need to close a WinForms app launched in this way is dealt with by over-loading the Closing EventHandler of all Forms and shutting down the Application when the last open form is closing.
Conclusion:
I've omitted code here, and other technical details, including the probable need for the Log-In Application and the dynamically loaded user-interfaces to share Interfaces. If there are further detailed questions on what's described here, I will respond with code, as appropriate.
The key idea is that the Log-In application be as "divorced" from the final interfaces loaded for different types of Users as possible for (what I hope are obvious) security reasons.
I have implemented each step described above to the "proof of concept" level.
«I'm asked why doesn't C# implement feature X all the time. The answer's always the same: because no one ever designed, specified, implemented, tested, documented, shipped that feature. All six of those things are necessary to make a feature happen. They all cost huge amounts of time, effort and money.» Eric Lippert, Microsoft, 2009
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I'm putting together what is essentially a template for listeners for a Message Queue server. The process I would like to have is the following
1) Connect to correct Message Queue
2) Listen for Message
3) Retrieve Message when it arrives
4) Process the message
5) Return results to the return queue
The way I would like to build the template is that all the steps but step 4 are handled by the template. Ideally I could then write individual libraries that could be plugged in to handle the processing of different types of messages to build out the individual listeners. I could script the builds for the all the listeners so if a change was made to the template I could run the script and rebuild all listeners at once or if there is a change to a individual listener I could just rebuild that listener.
Basic OOP seems to have fled my brain this today and I cannot think of how to do this. I'm thinking that I will need to use reflection to load the different dlls at runtime and then separate the listener executibles into their own directories so they can be placed with the correct library. Does this sound right? It seems that there should be an easier way but it escapes me at the moment.
Thanks for any help you can give.
The hurrier I go the behinder I get....
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I'd suggest looking at Microsoft Extensibility Framework[^] instead of rolling your own using Reflection...
A positive attitude may not solve every problem, but it will annoy enough people to be worth the effort.
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Hi,
In his recent blog[^] Uncle Bob come up with a situation that explains interface is harmful. Here is the code snippet taken from his blog.
public class Subject {
private List<Observer> observers = new ArrayList<>();
private void register(Observer o) {
observers.add(o);
}
private void notify() {
for (Observer o : observers)
o.update();
}
}
public class MyWidget {...}
public class MyObservableWidget extends MyWidget, Subject {
...
}
Here he explains that to implement Observer pattern done correctly, compilers must allow multiple inheritance.
So my question is why don't the MyObservableWidget implement using dependency injection like below to avoid multiple inheritance with greater degree of separation of concerns?
public class MyObservableWidget extends MyWidget {
private Subject subject;
public MyObservableWidget(Subject subject) {
this.subject = subject;
}
}
Of course the Subject class should be an abstract class. Please let me know your thoughts.
Thanks,
Pop
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"Ivory tower theorizing considered harmful." -- DMR
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I gather that this article needed the help of a proctologist with a torch.
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