Rule actions

Rule actions define what to do when the if part of the rule is true or false.

You define actions in the then and else parts of a rule. A rule action consists of at least one action phrase that the rule executes when the if part of the rule is true. It can also contain action phrases to execute when the if part of the rule is false.

You define actions in the following parts of a rule:

then: This part defines actions that the rule executes when the if part of the rule is true or when no if part exists.
else: This optional part defines actions that are executed when the if part of the rule is false. You do not have to declare an else part for a rule.

The then part of a rule must define at least one action. If the then or else part contains multiple actions, the rule executes the actions in their listed order.

Example of the then part

The following rule applies a discount of 15% only when the value of the shopping cart is more than $100, otherwise the rule applies no action.

if 
	the value of the shopping cart is more than $100 
then 
	apply a 15% discount on the shopping cart;

Example of the else part

The following rule applies a change when the conditions are met (then), or a different change when the conditions are not met (else):

if 
	'the loan report' is approved 
	and the loan grade in 'the loan report' is one of { "A", "B", "C" } 
then 
	in 'the loan report', accept the loan with the message "Congratulations! Your loan has been approved"; 
else 
	in 'the loan report', refuse the loan with the message "We are sorry. Your loan has not been approved";

Example of an action that calls methods

An action statement can invoke a method on a business term. You perform the method by using an action phrase from the rule vocabulary. The method can be a static method or a member of a class.

The following action statement uses apply to call the applyDiscountmethod, and display to call thedisplayMessage method.

then 
	apply a 10% discount; 
	display the message: "You received a discount!";

Rule actions for lists of business terms

You can define actions that a rule executes for each item in a list.

You use the operator for each <item> in <list> to apply actions to items in a list.

The following group of action statements applies to every item in the list of expensive items.

then 
	for each item in expensive items: 
		- apply 5% discount to this item; 
		- display the message: “A 5% discount has been applied”;