Exploring Camunda BPMN Elements: Part 1 — Task Types (1)

Introduction

BPMN (Business Process Model and Notation) stands as a pivotal tool for managing and optimizing business workflows. With Camunda, a renowned BPMN platform, organizations can efficiently streamline their processes. Within BPMN, there are several essential flow elements, including events, tasks, gateways, and connecting elements known as sequence flows. In this series, we begin by delving into the world of BPMN Task types and understanding how to select the right task for the job.

BPMN Elements

Before we dive into the intricacies of BPMN Task types, let’s take a moment to break down the key BPMN elements that comprise the foundation of business process modeling:

BPMN Flow Elements

• Events
  - Events represent something that happens during a process.
  - They can be classified into various categories, such as Start Events (trigger the process), Intermediate Events (occur within the process), and End Events (conclude the process).
• Tasks
  - Tasks are the work or actions within a business process.
  - They can be further categorized into different types based on their characteristics and use cases.
  - Tasks can involve users, services, scripts, business rules, or even be left manual.
• Gateways
  - Gateways determine the flow of a process.
  - They can be used to make decisions, merge or split flows, and define conditional routing.

BPMN Connecting Elements

• Sequence Flows
  - Sequence Flow represents the order in which elements are executed.
  - It connects events, tasks, and gateways, defining the flow of the process.

Understanding BPMN Task Types

Now, let’s focus on BPMN Task types. These tasks are the workhorses of your business processes, representing specific actions that need to be carried out. When defining a Task type, you’re specifying the nature of the work that needs to be done. Here are some common task types and when to define them:

User Task

• Describe it as a task assigned to a human user.
• Explain use cases like form submissions, approvals, or any task requiring human interaction.
• A User Task requires direct input from a person through the system before the process can move on. It’s for actions that are tracked and need confirmation that they’ve been done, typically involving form submissions or approvals within the Camunda interface.
• Example: “Review Application” is a User Task in an application process. Here, a reviewer must log into the system, evaluate the application, and submit their decision, which directly influences the flow of the process.

Key Takeaway

• Manual Tasks are for indicating human-required actions that the system acknowledges but does not track or wait on.
• User Tasks require active human participation within the system, pausing the process until the task is completed.

Service Task

• Explain that it represents an automated task, typically handled by software or a system.
• Provide use cases such as sending emails, making API calls, or data processing.
• Offer an example like an “Email Notification” task.

Business Rule Task

• Business Rule Task in BPMN is a task that automates processes by executing predefined business rules, often represented using decision tables. It’s particularly useful when decisions are based on specific conditions or criteria.
• Consider an e-commerce platform that offers discounts to customers based on their purchase history and current order details. The “Order Discount” Business Rule Task utilizes a decision table to determine the applicable discount.

Order Discount Criteria

Script Task

• Describe it as a task executed based on a scripting language (e.g., JavaScript).
• Provide use cases like calculations, data transformations, or custom logic.
• Following the Business Rule Task above, you can use a Script Task to apply the discount percentage to the order’s total amount. This Script Task executes custom JavaScript code to calculate the actual price, deducting the discount from the order total.

// Input values
const orderTotal = 150; // Example order total
const discountPercentage = /* You would obtain the 'discountPercentage' from your Business Rule Task or another appropriate source. */;

// Calculate the final price after applying the discount
const finalPrice = orderTotal - (orderTotal * (discountPercentage / 100));

// Output the calculated final price after discount
console.log(`Final Price After Discount: $${finalPrice}`);

Manual Task vs. Undefined Tasks

In the BPMN universe, particularly within the Camunda ecosystem, not every task is designed for automated execution. Two such non-executable elements are Manual Tasks and Undefined Tasks. Though they sit quietly within your process diagrams, their roles are distinct in comprehensive process planning.

Manual Task: The Human Element

• In Camunda BPM, Manual Tasks are akin to placeholders within your process diagram. They indicate a step that requires human action but, interestingly, the engine treats these tasks as if they are instantly completed. There’s no actual “waiting” for a human to finish; the process just moves along.
• Key Insight: The engine doesn’t monitor or manage the completion of Manual Tasks. When it encounters one, the process seamlessly continues to the next step as though the task was immediately completed.
• Example: “Prepare Meeting Room” could be a Manual Task in an event organization process. It signals the need to set up a room for an upcoming meeting, a task that’s done physically and doesn’t require input back into the Camunda system for the process to continue..

Undefined Tasks: The Canvas Awaits

• Undefined Tasks, in contrast, are placeholders or the “yet-to-be-defined” steps in your process. They highlight that a particular action is needed, but the what, how, and who are still undecided. These tasks are like open questions in your process, awaiting further analysis and specification.
• Example: “Handle Client Request” might be an Undefined Task within a service process, indicating that there’s an action to respond to a request, but the specific approach has yet to be established.

Both Serve a Purpose

While both Manual and Undefined Tasks are non-executable by the Camunda engine, they serve as important markers. Manual Tasks ensure the human-dependent steps are not overlooked, maintaining the integrity of the overall process. Undefined Tasks, on the other hand, provide flexibility in early process design, allowing you to map out the workflow without getting bogged down by details from the start.

Conclusion

In this article, we’ve delved into the fundamental BPMN flow elements, focusing on BPMN Tasks and the various task types, along with their respective use cases. Stay tuned for upcoming posts where we’ll dive deeper into topics like send and receive tasks.