Event-driven programming refers to the programming technique where the flow of the program is driven by recognition and handling of events such as mouse clicks, key presses, etc.

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Callbacks without concurrency? [closed]

To sync on the terms I will first give my perspective on what a callback function in the simplest possible terms: A callback function is a function that is executed as a response to a certain ...
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Event driven programming in Haskell

I'm new to Haskell, so this is more a high-level conceptual question. I've read this: https://wiki.haskell.org/Real_World_Applications/Event_Driven_Applications and it has this: run :: Domain -> ...
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Ensure that callbacks registration and triggering don't cause infinite recursion

I just spent a long, miserable week debugging a stack-overflow in a C++/Qt application. The fundamental problem was that I had a function that accepted a callback, and in certain cases the callback ...
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26 views

Event dispatcher and state

I'm using an event emitter similar to Node's, with the following pseudo code: event.on('onFuncBegin',(e)=>); event.on('onFuncEnd',(e)=>); let myFunc=()=>{ ...
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118 views

Use case for async/await?

Background Most of the applications that I write are hour long sequential tests for electronic equipment. The equipment under test has a specification that is a state-machine that looks like... Get ...
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1answer
30 views

Eventing solutions for java legacy applications too old for real JMS queue/topic eventing?

What are some architectural solutions that can mimic eventing for systems (Java) that are too old to implement eventing solutions, such as conventional Queue/Topic based JMS messaging? I have a ...
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What to use in case of waiting for something that is complete: delegates, events and/or thread

I try to give a concrete example. Create a semaphore for a crossroads. I have two semaphores. I have possibility to set a duration of semaphore 2 minutes, 5 minutes, 10m inutes etc. When one ...
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4answers
2k views

Event-driven programming: when is it worth it?

Ok, I know the title of this question is almost identical to When should I use event based programming? but the answers of said question have not helped me in deciding whether I should use events in ...
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1answer
125 views

For Web front end, if there are 20 JavaScript files loading, how to track down the mouseover handler?

For Web front end programming, since any JavaScript can set up an event listener for "mouseover" or "mouseenter" for an element, if we are to track down what is the code that is responsible for making ...
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53 views

Using events and event subscribers to create windows in a desktop application

I should probably open this by saying I do mostly Web applications at work, which obviously have some major differences from typical desktop stuff. I had a small Windows Forms program I'd made for ...
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1answer
117 views

“Who” should handle side tasks for events?

I'm currently on the process of creating a website/webapp. My application is based on Node JS with the express framework. My core backend concept consists of routers: handle http request. Like ...
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1answer
96 views

Why does Node not support several event loops in one Process?

As the title says, why does Node not support several event loops in one Process? The idea, is that node spawns a user decided number of threads, which each have an event loop. When a new callback is ...
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2answers
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What is the name for user-defined methods / functions that get called implicitly? [closed]

I want to mark such methods in my application code with a comment that highlights that these methods are expected to get called by the framework / compiler the application is written for, even if the ...
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4answers
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Why use plus equals += for event registration?

In C#, you register an event like: window.onClick += myHandler; But why use this instead of a "register" method that takes your handler and registers it. E.g.: window.registerOnClick(myHandler); ...
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0answers
76 views

Sharing identical events, with differing scopes, between client and server libraries, in a micro-service architecture

I have a shared user repository (id, name, e-mail, password, etc.) exposed as a REST service - and multiple independent web-sites accessing this REST service (from the back-end) as a means of sharing ...
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1answer
174 views

Is event sourcing only for when writes are rare?

I'm reading up on event sourcing and can't stop asking myself if it only makes sense in exotic situations where writes are very rare or military-grade auditing is required. A non-exceptional system ...
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2answers
195 views

Persistence models for Event Sourcing

I am intrigued by the Event Sourcing pattern but am struggling to design an event sourcing model and put it in concrete form. First off, I want to make sure that I understand the main use cases of ...
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1answer
154 views

Object Communication Design

Multiple top-level systems that communicate with each other via messages(events/commands). The Main class of the program wraps around all the systems and has a message dispacher component wich ...
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1answer
55 views

Identity propagation using Azure service bus

We currently have a platform with a SOA architecture in which the user's identity is propagated from the web application via middle tier services (REST and SOAP) until we actually query our data ...
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145 views

Web framework architecture with non-blocking I/O

There's been a lot of news in the enterprise world lately, specially in the web, and I've decided to build a small web framework on top of Netty to learn more about asynchronous programming and ...
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2answers
254 views

What's the simplest way to deal with events in C in this situation?

I'm writing a text-based game, in C. I want the game to handle NPCs movement and actions in the background, while the user is making his moves. I'd also use time-based events to tell the user when ...
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3answers
161 views

When is a event listener invoked during program execution?

I am using the Obervable-Observer Pattern. MyClass extends Observable{ invokeListeners(){ doSomething; setChanged(); notifyListeners();//This invokes onUpdate() in "implements ...
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3answers
224 views

Are imperative events an anti-pattern?

Are events which are intended to tell listeners to carry out explicit actions an anti-pattern? Imagine a worker service which raises the event WorkStarted at its beginning and the event WorkFinised ...
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1answer
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Should I use: One event multiple subscribers or multiple events multiple subscribers

I am writing a data acquisition application. I wondering whether I should use one event multiple subscribers or multiple events multiple subscribers. I am worried about performance. Also could I ...
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2answers
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Receive events in an event-loop, single-threaded

Let's say I have a program which consists of a main event loop. The event loop should check for tasks and if one exists, it is to be processed. The user interface consists of a GUI with buttons, for ...
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1answer
136 views

Structure project based on platform or design?

I have a medium sized project (~10,000 lines) that runs on Windows and Linux. However it is only specific components of the program that are platform dependent and are located in a folder called ...
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2answers
303 views

Observer pattern without state change?

My question is whether there is a similar pattern to Observer that does not imply a state change in the observed object. The following is a concrete example: I have a ConnectionFactory class which is ...
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1answer
98 views

What are the underlying patterns in systems allowing asynchronous operations?

Say I'm working with a system that allows async, nonblocking operations. If I queue up a set of those operations and specify their result buffer references: nonblocking_write( message, write_buffer ...
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1answer
102 views

Event action abstraction and trigger control

I am thinking of abstracting Event action in order to make further alteration/implementation/maintenance easy since the project I am currently working on has volatile requirement. So I thought of the ...
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6answers
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How to handle initial state in an event-driven architecture?

In an event-driven architecture each component only acts when an event is sent through the system. Imagine a hypothetical car with a brake pedal and a brake light. The brake light turns on when it ...
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1answer
321 views

Why do browsers clamp timeouts and intervals?

I've been working on some abstractions of setTimeout and setInterval in order to process large sets of data without blocking the event loop in the browser. Upon this, I have discovered that browsers ...
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1answer
534 views

Are there any design pattern to data binding in event driven architecture?

I develop a browser based game with node.js in back and HTML5 canvas in front-end. It use WebSockets for communication. My plan is to generate business events in client side, e.g.: "finishJob". ...
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5answers
6k views

When should I use event-based programming?

I have been passing callbacks or just triggering the functions from other function in my programs to make things happen once tasks complete. When something finishes, I trigger the function directly: ...
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3answers
172 views

Event Driven Objects/Framework on the Web [closed]

I am a desktop developer moving to web development. The guys who I am working with use procedural PHP, and coming from an event driven, objectified perspective (using WPF and C#.Net) I am completely ...
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1answer
162 views

Compose nested EventEmitters elegantly

I am developing a server-side JavaScript tool, and trying to do so in a modular way. I have a Parser class that is an EventEmitter - you call parse and it will eventually emit data and end events. It ...
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Should an event listener be called if attached after the event has already fired?

Should an event listener be called if it is attached after the event has already fired? What if the event will only be fired once? The first example that comes to mind is the ready event in jQuery. ...
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Hidden event handlers and their parameters

I'm having a bit of trouble understanding why has an event handler to be defined as a function. AFAIK, a function can be used as anonymous called procedure as event handler It defines a ...
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1answer
183 views

Software to access GSM Terminal, sending and receiving AT commands, validating results

I am currently implementing a software that uses a GSM terminal to perform actions. Actions can be sending messages, checking balance, receiving status report messages, setting the pin, ... The ...
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1answer
109 views

How do Event Bus and ReativeX interact with each other?

I wanted to look into communication/decoupling patterns and how to improve them. My current approach is to have a centralized commander in the form of an Event Bus and make him be the one to respond ...
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1answer
330 views

Do I need EventAggregator here?

I'm learning MVVM pattern with C#, WPF and .NET Framework 4.5.1. I'm using MVVM Light framework to do it and now I have a doubt. Reading the book Windows 8 MVVM Patterns Revealed I see that the ...
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1answer
409 views

Pass Event between Systems in a multi-threaded Entity-Component-System

Is there a way to pass Events between Systems in a multi-threaded Entity-Component-System that realizes the benefits of saving on system resources? I've read a german article about the ...
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3answers
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Are EventHandler<T> and IObservable<T> interchangable?

I have an object which will periodically raise an event based on an action performed in an application. This will be heard by any listener(s) and acted upon accordingly. I do not wish to use a ...
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2answers
143 views

Separate methods or single method with if statement?

I'm working on a .NET application and I'm wondering if I should use separate methods to handle the click events of two different buttons. They essentially do the same thing, just on different objects ...
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2answers
395 views

Deeper understanding of event loops and timers [closed]

I have a basic grasp of accepting clients without creating a thread for each connection using tools such as select and modern equivalents (kqueue, epoll). But where do I go from here? e.g async I/O ...
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1answer
105 views

Is it better to put an event on the top object or closer to where it's local?

Take the following basic structured code for example: class Player { public QuestLog QuestLog { get; set; } } Let us consider that "QuestLog" has the ability to fire off some events when things ...
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1answer
104 views

Pattern that prevents events to trigger themselves

I am working at the client-side part of a web application, that is responsible for getting answers from users for specific questions and storing and restoring them from the database (or cookies) and I ...
2
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0answers
50 views

Multiple handlers of an exception, and handling exceptions in the UI

Related to: Is onError handler better than exceptions? Premise I am writing a piece of library code that performs certain tasks, to separate concerns, we decided it should not write to a log or ...
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0answers
1k views

Updating GUI in 'realtime' using events

My Plan Have a system that holds some objects Have a winforms-form that displays some key values of these objects When certain changes occur(object gets add / removed / datat change): Update GUI ...
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Is there just one EventHandler class per application?

In a game I'm making I was about to add a MovementEventHandler, with events like "pre-character-movement" and "post-character-movement". But this class will do exactly the same as a future ...
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1answer
735 views

Should I omit the parameter “e” when using EventHandler<EventArgs>?

Whenever I am defining my own events, I use a pattern such as the following (which I believe is how the MSDN recommends doing it): public class MyEventClass { private bool _value; // Backing ...