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Nuclos server-side rules: event rules (insert, update, delete, status change, job), rule editor, providers, rule context, BigDecimal, avoiding endless loops. |
Language: Deutsch · English
Server-side rules
Java business rules on the server: bound to events, with access to business objects, providers and the full Nuclos API.
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| colour | Green |
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| title | Updated: Jul 2026 |
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| colour | Grey |
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| title | applies to Nuclos 4.2026.x |
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What are server-side rules?
The Nuclos API enables Java-based business rules that read and write content on certain events. When the other low-code means are not enough, implement complex validations, calculations, web service calls or automatic data changes here.
Menu: Configuration → Rule sets → Server-side rules
Events
| Event | Rule interface(s) | Example |
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| Create | InsertRule, InsertFinalRule | new record (e.g. invoice) |
| Update | UpdateRule, UpdateFinalRule | existing record (e.g. order) |
| Delete | DeleteRule, DeleteFinalRule | existing record |
| Status change | StateChangeRule, StateChangeFinalRule | e.g. open → reminder |
| Object generator | GenerateRule, GenerateFinalRule | e.g. delivery note from order |
| Button | CustomRule | user action in the layout |
| Job | JobRule | scheduled, recurring |
Rule editor
The rule editor is the central tool for editing rules. For convenient development/debugging there is also the IntelliJ integration.
| Hinweis |
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| title | Automatic compilation |
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The automatic compilation toggle temporarily disables compiling on save (useful for interdependent, not-yet-compilable rules). Note: uncompiled rules are not visible in the rule manager. |
The „automatic compilation“ toggle in the rule editor.
Application-specific objects
Nuclos automatically generates representing objects for business objects, status models, data sources and reports (with getters/setters). If this metadata changes, dependent rules no longer compile – a direct hint at what to adjust.
| Tipp |
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Decimal attributes are mapped to java.math.BigDecimal. Use BigDecimal.valueOf(double) instead of new BigDecimal(double) and always .divide(BigDecimal, RoundingMode) for division. |
Providers (supporting classes)
Providers offer functions to change content from rules: QueryProvider, StatemodelProvider, GenerationProvider, DatasourceProvider, BusinessObjectProvider, MailProvider, PrintoutProvider, ReportProvider, FileProvider.
Rules, subforms and the rule context
- In rules before the event (insert/update/state change/generate), changes to the context object via attribute setters are applied automatically;
delete() on dependent objects counts as a change. - In final rules an explicit
save() is needed to change other objects – this triggers their update/update-final rules.
Related pages
Server rule manager
Assign rules.
Open →
Rule execution order
Order per action.
Open →
