Working with rules

Rules are used to define logic and conditions for evaluating and processing healthcare data. FHIR rules can be used to validate data, create alerts and notifications based on certain conditions, or trigger workflows and other automated processes. Rules can also be used to extract specific data from a FHIR resource or to transform data from one format to another.

Using the extractValue() rule

To extract specific data value in the sample JSON below, include extractValue() and add the required parameters to the method in order to extract the required value.

"rules": [
    {
      "name": "familyName",
      "condition": "true",
      "actions": [
        "data.put('familyName', fhirPath.extractValue(Group, 'Group.name'))"
      ]
    },
    {
      "name": "familyId",
      "condition": "true",
      "actions": [
        "data.put('familyId', fhirPath.extractValue(Group, 'Group.identifier[0].value'))"
      ]
    },
    {
      "name": "familyLogicalId",
      "condition": "true",
      "actions": [
        "data.put('familyLogicalId', fhirPath.extractValue(Group, 'Group.id'))"
      ]
    }
  ],

Configuring the properties of the extractValue()

Property	Description	Required	Default
name	Provides a descriptive name for the rule to be extracted	Yes
condition	Indicates that the rule should always be evaluated	Yes	true
actions	Specifies the specific operations to be performed when the rule is evaluated	Yes

The "data.put()" function is used to store the extracted data in a data object, using a key-value pair format.

Using the evaluateToBoolean() rule

This rule is used within the rules engine or workflow to be able to determine whether an expression or condition is true or not. To evaluate specific data in the sample JSON below, include evaluateToBoolean() and add the required parameters to the method in order to determine whether the output is true or false.

    {
      "name": "isPregnant",
      "condition": "true",
      "actions": [
        "data.put('isPregnant', service.evaluateToBoolean(data.get('activeConditions'), \"Condition.code.text = 'Pregnant' \", false))"
      ]
    },

Configuring the properties of the evaluateToBoolean()

Property	Description	Required	Default
name	Provides a descriptive name for the rule to be extracted	Yes
condition	Indicates that the rule should always be evaluated	Yes	true
actions	Specifies the specific operations to be performed when the rule is evaluated	Yes	List
description	Provides relevant information about the rule to be evaluated
priority	Specifies the priority of the component. The priority value determines the order in which the components are evaluated and executed. Lower values indicate higher priority		1

Passing parameters to evaluateToBoolean()

1. context, e.g. data.get('activeConditions'), specifies the context or data from which the expression is being evaluated
2. FhirPathExpression, e.g. "Condition.code.text = 'Pregnant' \", specifies the expression to be evaluated. It contains the logical operators and variables that refernce values from the context
3. An optional defaultValue, e.g. false, specifies a boolean default to be returned if the expression results in an error or does not produce a boolean value

Using the generateTaskServiceStatus() rule

This rule is used within the rules engine or workflow to generate the correct service status when given the Task.status . Only one parameter is passed of the type TaskStatus. Below is an example:

...
    {
      "name": "serviceStatus",
      "condition": "true",
      "actions": [
        "data.put('serviceStatus', service.generateTaskServiceStatus(Task))"
      ]
    }

Reading practitioner details from shared preferences using rules

Below is a sample rules config to extract practitioner details from shared preferences. Note, the parameter passed inside extractPractitionerInfoFromSharedPrefs should be named as shown on the rule. i.e

ParamName	Description	SharedPrefKey
practitionerId	This is the assigned practitioner's ID	PRACTITIONER_ID
organization	This is the assigned practitioner's Organization	ORGANIZATION
careTeam	This is the assigned practitioner's Care Team	CARE_TEAM
practitionerLocation	This is the assigned practitioner's Location	PRACTITIONER_LOCATION

        {
          "name": "practitionerId",
          "condition": "true",
          "actions": [
            "data.put('practitionerId',service.extractPractitionerInfoFromSharedPrefs('PRACTITIONER_ID'))"
          ]
        },
        {
          "name": "careTeam",
          "condition": "true",
          "actions": [
            "data.put('careTeam',service.extractPractitionerInfoFromSharedPrefs('CARE_TEAM'))"
          ]
        },
        {
          "name": "organization",
          "condition": "true",
          "actions": [
            "data.put('organization',service.extractPractitionerInfoFromSharedPrefs('ORGANIZATION'))"
          ]
        },
        {
          "name": "practitionerLocation",
          "condition": "true",
          "actions": [
            "data.put('practitionerLocation',service.extractPractitionerInfoFromSharedPrefs('PRACTITIONER_LOCATION'))"
          ]
        }