In that case, management is forced to make expensive choices to replace or upgrade these platforms, which have proven to be reliable over decades. That should not always be the case for those that chose to implement a middleware. Existing knowledge of WSO2 gained through an Enterprise Service Bus (ESB) or API implementation will boost IT’s ability to drive the innovative change.
This series of blogs will demonstrate how WSO2 ESB development knowledge, combined with a tacit understanding of the (LOB) IT team, can be used to implement a cost-effective process with the WSO2 Enterprise Integrator.
The four-eyes principle
The typical implementation of LOB decisions is role based, with a single form built into the logic of the application. When it comes time to replace that with a dual review process, it becomes clear that rewriting that accumulated logic will be costly.
This dual review or the four-eyes principle, in a nutshell, states that two roles or organizational units must independently review / approve a business case. The Business Process Modelling and Notation (BPMN) diagram in figure 1 visually depicts this principle.
Figure 1: Four-eyes principle
The process in the diagram has the following steps with the decisions in between.
- Initiation
- First review
- Second review
- Implementation
- End
Figure 2: First review process
The start of the review process, this sub-process gets executed. Any additional data is collected with a system call. Then a human interaction occurs to review the data. This sub-process ends with a recorded choice of approval or rejection. The primary process evaluates the decision in this first review before moving to the next step.
Figure 3: Second review process
As it’s clear by now the diagram for the second review is identical to the first review process. The only differentiable aspect here is the lane name in the image. As with any procedure, there can be exceptions. Figure 4 depicts the exception handling cases.
Figure 4: Exception handling process
Conclusion
At this stage, BPMN models represent the requirements of the four-eyes business. In subsequent parts of this series, I will show how to develop the models in the diagrams using WSO2 EI tooling. I will also demonstrate how to extract & transform data within LOB systems using the WSO2 EI data service profile, and deploy & run the process into the WSO2 EI business process profile.
