[Full modeling] questions about the direction of the arrow in the UML sequence diagram

An old programmer of Pancake Hall 2017/10/12 9:40:59

Qingrun

Ask a question, please.

Green Run 2017/10/129:44:47

Said

Let's be polite about this. If you have any questions, just say that, as long as I have the time, I will reply directly.

An old programmer of Pancake Hall 2017/10/12 9:45:31

How can you do that, you're busy.

I know

It's about the UML sequence diagram.

General messages are left-to-right

Can you go from right to left?

Green Run 2017/10/129:46:16

All right, don't be a phony.

An old programmer of Pancake Hall 2017/10/12 9:46:16

Like this.

Green Run 2017/10/129:46:39

Timing diagram, it doesn't matter if you do it from left to right or right to left, it's important that you reach a consensus within your team.

An old programmer of Pancake Hall 2017/10/12 9:46:56

Know

Green Run 2017/10/129:47:13

The reason for this from left to right is because the information generated from Europe occurs in a way that is left to right.

Green Run 2017/10/129:48:10

Mosquitoes come out, OK, I just did not see the mosquitoes out of the way, and sent a voice.

In addition, the message can be sent by right-to-left, but mostly by right-to-left default Yes, return.

In fact, it is not forbidden to send from right-to-left instructions or method calls, which depends on the structure of your system, or the presentation of the architecture layer.

An old programmer of Pancake Hall 2017/10/12 9:49:08

Well

I am a time series diagram, coexisting two

Green Run 2017/10/129:49:35

A better architecture, not mandatory, from left to right, but everyone will feel that from left to right can be better to show the level of the message, as well as the level of the method call, this is the best.

No matter, a database inside the coexistence of two, business process, which can be done, I have done so before.

An old programmer of Pancake Hall 2017/10/12 9:51:16

Ha

Green Run 2017/10/129:53:28

Time series diagram, not a database.

An old programmer of Pancake Hall 2017/10/12 9:55:31

I may not have made myself clear before, I would like to express this figure

Green Run 2017/10/129:56:49

Oh. In this case, there must be a problem with the design, it is not recommended to do so.

And there must be a more reasonable way to solve such a performance. Otherwise, the system will have a cyclic invocation of the deadlock situation, the future is not a good solution.

An old programmer of Pancake Hall 2017/10/12 9:57:25

Not so bad.

Green Run 2017/10/129:57:39

The operation is not good, it will be very serious. Future patches are not good to play.

An old programmer of Pancake Hall 2017/10/12 9:57:58

My question now is, you look at me in the middle of the line, according to tradition, the general is to make a call to the right

I also want to make a call to the left.

In this tangle, you are a UML expert, so come and ask

Green Run 2017/10/129:58:39

Business implementation logic is not a problem, your architecture is how to do.

I think there must be a solution to this.

An old programmer of Pancake Hall 2017/10/12 9:58:53

This diagram does not currently involve a specific design, that is, something that expresses a preliminary idea.

Green Run 2017/10/129:59:34

If there is no specific design, such ideas, there will be problems, I used to do training and projects have been told, really do not see one, even should not appear this situation.

An old programmer of Pancake Hall 2017/10/12 9:59:46

。

Green Run 2017/10/1210:00:03

The hierarchical structure and invocation of the system, in addition to message sending and emergency temporary storage, generally do not have to cross multi-layered form.

An old programmer of Pancake Hall 2017/10/12 10:01:57

Let me think of a scene.

Let me think of a scene, we'll talk.

An old programmer of Pancake Hall 2017/10/12 10:05:05

Module 2 notifies Module 1 after calling Module 3 to complete an operation,

Then module 1, to invoke Module 2 to get the result of the operation

Such a scene

Green Run 2017/10/1210:06:18

This diagram, Module 2 is the active side, no problem.

An old programmer of Pancake Hall 2017/10/12 10:06:26

Good good

Green Run 2017/10/1210:06:27

If 1 to 2 still has a call, it is wrong.

An old programmer of Pancake Hall 2017/10/12 10:07:36

My module 1 to Module 2 still has the call ....

Green Run 2017/10/1210:07:53

Yes, if there is 4, there is a problem.

An old programmer of Pancake Hall 2017/10/12 10:07:57

Why is that?

Green Run 2017/10/1210:08:28

I use the voice, the text is not good to play.

An old programmer of Pancake Hall 2017/10/12 10:08:43

Of course, calling Method 4 must be after calling Method 3.

Green Run 2017/10/1210:08:52

An old programmer of Pancake Hall 2017/10/12 10:10:21

I do it from top to bottom in chronological order.

Green Run 2017/10/1210:11:03

Wait, don't worry, I'll show you the picture.

Green Run 2017/10/1210:12:16

Note: This figure is from the illustrations in my book Fixing, "software engineering for the whole process of modeling implementation"

An old programmer in Pancake Hall 2017/10/1210:14:13

It's okay, I Digest and Digest

Green Run 2017/10/1210:14:53

Good. Your question, which is introduced in my book, is a use error, a mistake that can cause bad problems in expressing and transmitting information.