Error Handling

What happens when a then() throws, and what happens when a Rule is run detached.

Error Handling

A then() consumer that throws

If a then() consumer throws, RuleBox records the rule as FAILED in the audit trail (see Auditing Rules) before the exception is re-thrown to the caller. That means ruleBook.getRuleStatus() reliably reflects a mid-chain failure - you don't have to catch the exception yourself just to find out which rule blew up:

try {
	myRuleBook.run()
} catch( any e ) {
	writeDump( myRuleBook.getRuleStatus( "myFailingRule" ) ) // "FAILED"
	rethrow;
}

Running a detached Rule

Calling run() directly on a Rule that was never added to a RuleBook via addRule() throws a named exception, RuleBox.RuleNotAttachedException, rather than a cryptic null-reference error:

var orphan = getInstance( "Rule@rulebox" )
orphan.run() // throws RuleBox.RuleNotAttachedException

Always build rules through a RuleBook (either a subclass's defineRules(), or the Builder) so every Rule is attached before it's run.