Oracle Visual Builder: Applications That Outlive Their First Release · Module 8 · Action chains and events
Failure inside a chain
Lesson 84 of 176 · 3 min
What happens BY DEFAULT, which is USUALLY NOTHING VISIBLE. Catching it, and DECIDING WHAT THE USER SHOULD BE TOLD. This is the most important lesson in the module, because the default behaviour of a failing chain is the worst possible behaviour and it requires no mistake to produce. WHAT HAPPENS BY DEFAULT IS THAT THE CHAIN STOPS. The failing step does not complete, the steps after it never run, and nothing appears on screen. The user pressed Save, no error appeared, and nothing was saved. WHICH IS WORSE THAN AN ERROR MESSAGE BY A LONG WAY, BECAUSE THE ABSENCE OF AN ERROR IS READ AS SUCCESS. A person who sees no complaint assumes the record is saved and moves on — and finds out days later, or does not. SO EVERY CHAIN THAT CALLS A SERVICE NEEDS A FAILURE PATH, AND THAT IS NOT AN EDGE CASE. Module 6 Lesson…
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In this module: Module 8 · Action chains and events
- 1What an action chain isFree preview
- 2Events: what can start one
- 3The common actions
- 4Conditions and branching
- 5Chains that call chains
- 6Waiting: asynchronous steps
- 7Failure inside a chain
- 8JavaScript, and when to reach for it
- 9Keeping a chain readable
- 10Debugging one that misbehaves
- 11Logic that does not belong here
- 12What breaks: four action chain failures
- 13Lab briefing · A chain that survives being read