Warm tip: This article is reproduced from serverfault.com, please click
class-diagram events java spring uml

How to represent in UML that one class calls another class method when publishing spring event

发布于 2020-12-03 13:09:28

I want to draw UML diagram which represents my Spring boot application. I'm new in UML and don't know how to represent an interaction between two classes that uses other classes for it. I have a class that publishes spring events and a class which handles such events. Publisher example:

 import org.springframework.context.ApplicationEventPublisher;
    
    class Publisher {
    ApplicationEventPublisher springPublisher;
    
    public publishEvent() {
    springPublisher.publishEvent(new SomeEvent());
    }

}

Handler:

import org.springframework.context.event.EventListener;
  
 class EventHandler {
    @EventListener
    public handleEvent(Event event) {
    // some processing
    }
}

So, when I publish some events via Spring ApplicationEventPublisher my handler handles events via method annotated with @EventListener. But it is not a direct calling of the method. How I can illustrate it on the UML diagram?

enter image description here

Questioner
Valeriy K.
Viewed
0
分享
Christophe 2020-12-04 05:23:05

The class diagram

As qwerty_so rightly pointed out, in a class diagram, we do not represent interactions: we represent structure, such as classes, association between classes, and dependencies:

You may therefore want to show a dependency to the common ApplicationEvent:

enter image description here

The Spring magic

I'm not a Spring expert, but I understand that behind the "spring magic" is the annotation which hides an automatic registration of the listener to publisher, based on the signature of the annotated method.

You could be tempted to show in your model the (automatic) association between the listener and the publisher. But IMHO, this would not reflect well your design, since your model would hardwire the magic, whereas your code is dynamic in this regard. This is why the simpler diagram I show above, seems more appropriate: the magic is caused by the common Event denominator. Just use the right intermetiary type.

The interactions

If you want to show the dynamics of the interactions, it's a little more complex. You could for example use an sequence diagram, and encabulate the magic in a :SpringFramework lifeline, and materialize the automatic registration with messages sent to this "virtual" lifeline. Moreover:

  • Event sending would then be a message from the publisher to the framework,
  • Event listening would be a message sent by the framework to one or several listener.

It's not the real details. But the readers of your diagram do not need to know these details (except if they'd belong to the spring development team). So keep it as simple as possible, but not more :-)

qwerty_so 2020-12-03 22:24:38

You must somehow have access to a time machine to produce all these answers :-)

Christophe 2020-12-03 22:32:17

@qwerty_so you made my day :-)

热门github

1
Implementation of paper - YOLOv9: Learning What You Want to Learn Using Programmable Gradient Information
2
A Windows and Office activator using HWID / Ohook / KMS38 / Online KMS activation methods, with a focus on open-source code and fewer antivirus detections.
3
Get up and running with Llama 2, Mistral, Gemma, and other large language models.
4
该项目可以让你通过订阅的方式使用Cloudflare WARP+，自动获取流量。This project enables you to use Cloudflare WARP+ through subscription, automatically acquiring traffic.
5
Multi functional app to find duplicates, empty folders, similar images etc.
6
Xray panel supporting multi-protocol multi-user expire day & traffic & ip limit (Vmess & Vless & Trojan & ShadowSocks & Wireguard)
7
The Free Software Media System
8
lightweight, standalone C++ inference engine for Google's Gemma models.
9
📚 Freely available programming books
10
A collective list of free APIs
11
1️⃣🐝🏎️ The One Billion Row Challenge -- A fun exploration of how quickly 1B rows from a text file can be aggregated with Java
12
🎓 Path to a free self-taught education in Computer Science!
13
Curso para aprender el lenguaje de programación Python desde cero y para principiantes. 75 clases, 37 horas en vídeo, código, proyectos y grupo de chat. Fundamentos, frontend, backend, testing, IA...
14
This repository contains System Design resources which are useful while preparing for interviews and learning Distributed Systems
15
Mamba is a new state space model architecture showing promising performance on information-dense data such as language modeling, where previous subquadratic models fall short of Transformers. It is based on the line of progress on structured state space models, with an efficient hardware-aware design and implementation in the spirit of FlashAttention.