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This article will explain in detail the example analysis of the object flow in the UML activity diagram drawn by EA. The editor thinks it is very practical, so I share it with you for reference. I hope you can get something after reading this article.

One thing that is different is the part of the red box in the following picture.

This part is today's content, object flow.

Semantic meaning

The control flow (control flow) describes the flow of execution tokens (execution focus) between two active nodes. There is another case where data or objects need to be transferred between two activities in addition to the execution token, which is called an object stream (object flow).

Representation method

There are two ways to represent the object flow, one is to divide the control flow into two, with the transferred object or data in the middle.

Another representation is to connect the inputs and outputs of two active nodes.

It needs to be added that the small square next to Action is called ActionPin, which is used to represent the input / output pins of Action.

Drawing method

The first method of representation

Drag the Object icon below to the appropriate location

Select the control flow icon, connect the Action to the object, and the object to the next Action

The second method of representation

Select the object stream icon below to connect the source Action and the destination Action.

Of course, you can also select the Action context menu-[New child element]-[Action pin] to add input / output pins and select the control flow icon and connect.

Summary

The simplest question is, why do you need an object stream?

First of all, let's look back at the final example of an introduction to activity diagrams.

We know that whether we write a program or read a program, we should pay attention to the data flow in addition to the program flow. The object flow in the UML activity diagram can be used to express the data flow, but the flowchart is not.

Here's what it looks like after we supplement the object stream.

The object graph clearly shows the direction of the data between the various processes.

It is important to add that Action or Activity can be executed only if all the execution tokens on the input control flow / object flow arrive.

Now you can look back at the flow chart at the beginning of this article and understand it as follows:

After the UI process receives the event from the copy process, it is transferred to decision node.

Decision node invokes different processes and transfers the event to that processing depending on the type of event.

The called processing is processed accordingly according to the information stored in the event.

This is the end of the article on "sample Analysis of object flow in EA drawing UML activity Diagram". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, please share it out for more people to see.

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