Application and Design of the basic flow control mode (6, 7, 8, and 9)

The following four modes are described: Multi-choice, structured synchronizing merge, multi-merge, and structure discriminator, it is generally classified into advanced branching and synchronization patterns ).

1. Classification of Models

Why are these models called "advanced? Starting from these models, various workflow products are opened at the technical level. Because of the technical complexity, many workflow products/standards may not be directly supported, and even some products cannot describe these process models. If some friends who have studied earlier workflow modes may find that the synchronizing merge mode is absent, because they have already been split into three modes: structured synchronizing merge, acyclic synchronizing merge, and general synchronizing merge.

2. Understanding of workflow in Novels

The workflow mode is a summary of the actual business and a development history of the workflow system design. We can see that the preceding five basic process control modes are based on the simplest flowchart and the concurrent processing of computers. At this time, most people's understanding of the workflow system remains at this level extended by software technology (that is, the way to process the process in the software technology ). These patterns are exactly the branch/merge patterns that the WfMC organization begins to agree on (see WFMC-TC-1011, http://www.wfmc.org/standards/docs/TC-1011_term_glossary_v3.pdf for details ). However, the basic mode is not enough to express the actual business logic in the actual application process, which makes it more and more important to study the workflow mode in depth.

The introduction of the four advanced processes allows us to explore the path explored by our predecessors. Its basic features clearly show the two development directions of workflow Flow Control: end user participation and context Association. The so-called end-user participation determines the direction (Branch) of the process path based on the business data (or the choice of end-user). Context Association is in front of several bodies, A branch is dynamically generated due to the user's choice. At a certain point, the merge method (merge) must be determined based on the preceding branch ). In this way, a clear concept and direction will be established: the research on the workflow process model is no longer as concerned with the topology structure of the process in the past, instead, we will be more concerned with the summary of the actual business. (Sighs, when will the Chinese counterparts reach this level ?)

3. Application

If there is no mathematical tool to verify this part of the model, we recommend that you try your best to use it. Several matching suggestions are listed below:

• Multi-choice → multi-Merge

• Multi-choice → structured synchronizing merge

• Parallel split → structured Discriminator

Of course, there is no restriction on the matching method, but when pairing, You need to carefully repeat (there are mathematical methods available, this opportunity to talk about it separately) to avoid uncontrollable situations. It is noted that multi-choice can summarize the branch modes of and XOR. Therefore, theoretically, some additional processing can replace multi-choice with and XOR (the additional processing here is to let structured class nodes obtain the above information ).

It is worth noting that the multi-merge mode is actually clone several different process branches. Finally, how to merge these generated branches depends on the specific algorithm of the specific workflow product. If the algorithm generates different branches on the graph structure (that is, the topology of the graph is used to implement this mode), you can use an and-join or structure discriminator to merge them.

4. Instance

These process models have already expressed some complex realistic structures, considering a real business: An enterprise, generally planned activity schedule management. First, draft the planning scheme, which may involve the participation of different departments. The specific department is determined according to the content of the plan. After drafting the scheme, submit it to the department owner who needs to participate for approval. After a department head approves the plan, they can arrange and execute the plan. Consider the following design:

　

Note: Why can't I directly return to the previous drafting scheme after the manager's approval is rejected? In fact, this can also be done. As long as you judge in the business of drafting the scheme, if it is rejected for approval, the subsequent path selection can only be the corresponding return step, this design requires that several variables be saved in the process instance to identify the returned path selection. However, this method requires careful consideration of the Code for business processing. For example:

There are many business examples in addition to structure discriminator, which will not be listed here. Structure discriminator: I have never met any actual business, but the business mentioned by plutoner is also very practical.

5. Summary

The so-called advanced mode focuses more on the choice of end users and introduces a more complex dynamic path selection method. Here we can see the progress of the previous research workflow. I think the in-depth research on these models is the beginning of making workflows independent into a complex system. If a workflow is like a general flow chart, there is no such booming market. If the development of these models is sufficient to cover most of the business methods, workflow must be the most important cornerstone of informatization.