There are two key words in Business Process Management Notation (and Language) or BPMN for short that very often seemed to be missed. The first is "business" the second "management". In this posting I will discuss the significance of the first, and how you are in control of that.
In BPMN the word business does not wants to express that it is "just" about modeling business processes. The idea is also that these models should be understandable, or even created by the business. Now one can argue that with respect to the latter BPMN does not always seems to deliver on the promise, or at least not for every business. But I know of a few cases where the business analyst creates the non-technical versions of the model (level 1, and 2 as Bruce Silver would call them), and I know of a significant amount of cases where the business or at least the analyst is able to understand BPMN process models. That is to say, if these models have not been cluttered with technical details.
Unfortunately this cluttering happens quicker that you wish, and too often the executable process models are almost beyond comprehension for the business, while there is no good reason for that. And that is too bad, because you then miss the opportunity to let the executable process model being validated by that business. Observing how process modeling is done at some of my projects, unfortunately I have to conclude that quite a few people are not aware of the problem or don't know how to prevent it, and as I did not (yet) found any references that gives a comprehensive overview of the options offered by the Oracle BPM Suite that can help you out, I discuss them in the following.
Except for using it to hide technical details, embedded sub-processes can also be used to determine a scope. This can be done from a business perspective (for example to determine a scope of activities that might be repeated or for which multiple instances should be handled in parallel), but also from a technical perspective (for example as a scope for temporary variables, or exception handling).
The issue I often see with embedded sub-process in action, is that developers very often do not bother collapsing them, still exposing technical details to the business.
One should be aware of a couple of aspects concerning embedded sub-processes. The first is that they are not reusable (meaning you cannot use them elsewhere in the same or any other process model). The second that they come with a little overhead from an audit perspective, as every embedded sub-process results in 2 extra entries (one for the start and one for the end of it).
Going back to the step in the example where we want to save order data, and let's assume the order has to be updated more than once, than this makes it a typical candidate for reuse. In the following example a reusable "Order Storage" reusable sub-process has been created that contains this functionality. It has been made a little bit more complex by including a notification activity that will notify the sales representative every time an update of the order has taken place.
The reusable sub-process has access to the /project/ variables (by value), and its own /process/ variables. In other words, the reusable sub-process has access to the "order" project variable. A choice has been made to pass on the email address of the one that has been notified, as an argument. In the reusable sub-process this email address is stored in a (local) "email" process variable.
The choice to define a variable at project versus process level should be made carefully. Project variables are global variables with the following properties:
Finally, up to version 12.1.2 a Call activity in a BPM project makes it incompatible with any other revision, meaning that you cannot migrate instances. Period. Not even when you deploy the same revision without changing any bit of your code. For most customers I work with, this is a major limitation, and some therefore choose not to use reusable sub-processes.
In BPMN the word business does not wants to express that it is "just" about modeling business processes. The idea is also that these models should be understandable, or even created by the business. Now one can argue that with respect to the latter BPMN does not always seems to deliver on the promise, or at least not for every business. But I know of a few cases where the business analyst creates the non-technical versions of the model (level 1, and 2 as Bruce Silver would call them), and I know of a significant amount of cases where the business or at least the analyst is able to understand BPMN process models. That is to say, if these models have not been cluttered with technical details.
Unfortunately this cluttering happens quicker that you wish, and too often the executable process models are almost beyond comprehension for the business, while there is no good reason for that. And that is too bad, because you then miss the opportunity to let the executable process model being validated by that business. Observing how process modeling is done at some of my projects, unfortunately I have to conclude that quite a few people are not aware of the problem or don't know how to prevent it, and as I did not (yet) found any references that gives a comprehensive overview of the options offered by the Oracle BPM Suite that can help you out, I discuss them in the following.
Embedded Sub-Process
The embedded sub-process is one of the options that most people are aware of, and (generally) reasonably well used. In the example below an embedded sub-process with name "Store Order" contains a script activity "Create Message Header" that constructs the header for the message to be used in the service call activity "Save Order Data". By simply collapsing the embedded sub-process the technical details of how an order is stored, can be hidden for the business that typically does not want to know that a header needs to be created. One could argue they should not even be interested in the fact that this is done synchronously (using a service activity) instead of asynchronously (using a send and receive activity), which also is conveniently hidden by the embedded sub-process.
Except for using it to hide technical details, embedded sub-processes can also be used to determine a scope. This can be done from a business perspective (for example to determine a scope of activities that might be repeated or for which multiple instances should be handled in parallel), but also from a technical perspective (for example as a scope for temporary variables, or exception handling).
The issue I often see with embedded sub-process in action, is that developers very often do not bother collapsing them, still exposing technical details to the business.
One should be aware of a couple of aspects concerning embedded sub-processes. The first is that they are not reusable (meaning you cannot use them elsewhere in the same or any other process model). The second that they come with a little overhead from an audit perspective, as every embedded sub-process results in 2 extra entries (one for the start and one for the end of it).
Reusable Sub-process
A reusable sub-process is created as a separate process. The only thing that distinguishes it from other types of processes, is that it has a none start as well as a none end event, and it cannot have an initiator activity. As the name already suggests, a reusable sub-process is never started directly, but only by calling it from some parent process. This is done by the Call activity.Going back to the step in the example where we want to save order data, and let's assume the order has to be updated more than once, than this makes it a typical candidate for reuse. In the following example a reusable "Order Storage" reusable sub-process has been created that contains this functionality. It has been made a little bit more complex by including a notification activity that will notify the sales representative every time an update of the order has taken place.
The reusable sub-process has access to the /project/ variables (by value), and its own /process/ variables. In other words, the reusable sub-process has access to the "order" project variable. A choice has been made to pass on the email address of the one that has been notified, as an argument. In the reusable sub-process this email address is stored in a (local) "email" process variable.
The choice to define a variable at project versus process level should be made carefully. Project variables are global variables with the following properties:
- In case of functionality that is executed in parallel, one should be careful that the parallel threads do not make conflicting changes to the same project variable.
- Simple type project variables are mapped to protected attributes (also known as mapped attributes or flex field), of which there is a limited number (for example 20 protected text attributes). Their values are stored in separated columns (instead of part of the process payload).
- The lifespan of a project variable is from its initialization up to the end of the (main) process instance.
Finally, up to version 12.1.2 a Call activity in a BPM project makes it incompatible with any other revision, meaning that you cannot migrate instances. Period. Not even when you deploy the same revision without changing any bit of your code. For most customers I work with, this is a major limitation, and some therefore choose not to use reusable sub-processes.
Process As a Service
The next alternative to a reusable sub-process is the process-as-a-service, which means that you start it with a message start event or send activity. Any response is returned by a message end event or receive activity. As long as the process-as-a-service is part of the same BPM project (composite) it can make use of the project variables, but only by definition, not by value. So all data has to be mapped to and from the process. You can put the process in the same composite, or put it in a composite of its own. The criteria to do the latter would be reuse over composites. When in a separate composite, you cannot reuse the business objects, nor the project variable definitions.
From a functional perspective, the process-as-a-service is equivalent to a reusable sub-process. From a technical perspective it requires more work if you implement it in a separate composite, and it will add extra overhead to auditing (not only BPM auditing, but also every instance will have its own entry in the COMPOSITE_INSTANCE and CUBE_INSTANCE tables). In 11g you will also have to create some custom mechanism to propagate cancellation of the parent instance to child instances, but in 12c this is automatically done (see also http://kettenisblogs.blogspot.nl/2015/08/oracle-soabpm-12c-propagation-of-flow.html).
Since 12c you can "detail" an activity. With that you can hide logic that is tightly related to an activity, but has to be done using an activity of its own. From the outside a detailed activity looks like any other activity, and keeps the original icon associated with it. The fact that it is detailed you can see by a + sign at the bottom, very much like an embedded sub-process. And basically that is what it is, a specialized embedded activity. You can even have local variables, and in the structure pane it is represented as an embedded sub-process. Again, to keep the business process a "business" process you should try not to get over-exited and put all sorts of logic in it that really belongs somewhere else. Use it only for logic that is tightly coupled to the main activity, but of any importance to the business.
In the following example I have implemented a call to some service that has to happen right after the user activity. It is a technical service call that we don't want to bother the business with, as it concerns a call to a service to confirm the order to the customer. As far as the business is concerned, this is an integral part of the Contact Provider activity, and they should not care if that service is called from the UI or from the process for that matter.
From a functional perspective, the process-as-a-service is equivalent to a reusable sub-process. From a technical perspective it requires more work if you implement it in a separate composite, and it will add extra overhead to auditing (not only BPM auditing, but also every instance will have its own entry in the COMPOSITE_INSTANCE and CUBE_INSTANCE tables). In 11g you will also have to create some custom mechanism to propagate cancellation of the parent instance to child instances, but in 12c this is automatically done (see also http://kettenisblogs.blogspot.nl/2015/08/oracle-soabpm-12c-propagation-of-flow.html).
Detail Activity
Since 12c you can "detail" an activity. With that you can hide logic that is tightly related to an activity, but has to be done using an activity of its own. From the outside a detailed activity looks like any other activity, and keeps the original icon associated with it. The fact that it is detailed you can see by a + sign at the bottom, very much like an embedded sub-process. And basically that is what it is, a specialized embedded activity. You can even have local variables, and in the structure pane it is represented as an embedded sub-process. Again, to keep the business process a "business" process you should try not to get over-exited and put all sorts of logic in it that really belongs somewhere else. Use it only for logic that is tightly coupled to the main activity, but of any importance to the business.
In the following example I have implemented a call to some service that has to happen right after the user activity. It is a technical service call that we don't want to bother the business with, as it concerns a call to a service to confirm the order to the customer. As far as the business is concerned, this is an integral part of the Contact Provider activity, and they should not care if that service is called from the UI or from the process for that matter.
Hope you can make good use of this, and let me know if you have any other suggestion!!
