Skip to main content

Controlling Form Flow with Rules

In the Dynamic Forms solution, the Decision Service—not the front-end—is responsible for controlling the stage-by-stage flow of the form. A "stage" is a unique identifier representing the user's current position in the form's state machine. This control is achieved by using the current stage number as a filter for your rules and explicitly setting the next stage number on the root UI entity.

The Stage-Based Rulesheet Pattern​

A best practice is to organize your ruleflow so that each stage of your form corresponds to its own rulesheet. The key is to use the UI.currentStageNumber as a precondition to ensure only the correct rulesheet executes.

In the Request: UI.currentStageNumber (Precondition)​

When the front-end component makes a request to the Decision Service, it specifies which stage to execute by setting the UI.currentStageNumber attribute. You should use this in the Preconditions section of your rulesheet to ensure it only runs when the user is on the corresponding stage.

Example Rulesheet Precondition for Stage 1: Corticon Studio screenshot

UI.currentStageNumber == 1

In the Response: UI.nextStageNumber (Action)​

Within your rulesheet's actions, you must set a value for UI.nextStageNumber. This attribute tells the front-end which stage to render next. When the user proceeds, the front-end will use this value as the currentStageNumber for the next request. If you do not set this attribute, the form will not advance.

The Decision Service response may also contain currentStageNumber and an optional currentStageDescription. These are for troubleshooting and debugging purposes; the front-end does not use them for navigation.

Example: A Two-Stage Form​

Imagine a form with two stages.

Rulesheet 1: "Handle Stage 1"

  • Precondition: UI.currentStageNumber == 1
  • Purpose: Validates the data from stage 1 and decides where to go next.
  • Action: UI.nextStageNumber = 2

Rulesheet 2: "Handle Stage 2"

  • Precondition: UI.currentStageNumber == 2
  • Purpose: Processes the data from stage 2.
  • Action: UI.nextStageNumber = 3 // Or perhaps a "confirmation" stage

Conditional Navigation​

To create dynamic navigation, you simply add conditions to your rules that set nextStageNumber differently based on user data.

Example: Directing the user to a different stage based on their "experienceLevel".

Rulesheet: "Handle Stage 1"

  • Precondition: UI.currentStageNumber == 1

  • Rule 1: Novice User

    • Condition: User.experienceLevel == 'Novice'
    • Action: UI.nextStageNumber = 3 // Go to the "Simple" stage

  • Rule 2: Expert User

    • Condition: User.experienceLevel == 'Expert'
    • Action: UI.nextStageNumber = 4 // Go to the "Advanced" stage

This pattern gives the rule author complete and precise control over the user's journey.