Validation behavior

Dispatch model

ValidationService.validate(data, schema) chooses validator by SchemaType using ValidatorDispatcher:

• OBJECT -> ObjectValidator
• ARRAY -> ArrayValidator
• other types -> PrimitiveValidator

Object validation order

ObjectValidator evaluates in this order:

1. Resolve $ref when schema is reference and resolver is wired.
2. Resolve $dynamicRef if present and no static reference.
3. Ensure data is Map<?, ?> (null values are skipped).
4. Composition and conditionals (order is as follows):
   • allOf: all subschemas must pass.
   • anyOf: at least one subschema must pass.
   • oneOf: exactly one subschema must pass.
   • not: instance must NOT match the subschema.
   • if/then/else: branch according to the if condition.
5. Validate required fields.
6. Validate declared properties that exist in input.
7. Validate unknown keys with patternProperties (regex matches).
8. If still unmatched, enforce additionalProperties (boolean or schema).
9. Finally, enforce unevaluatedProperties for any property not covered by steps 6–8.

Array validation order

ArrayValidator evaluates in this order:

1. Ensure data is List<?>.
2. Apply minItems and maxItems constraints.
3. Apply uniqueItems constraint.
4. Validate prefixItems schemas for the first N items (tuple validation).
5. Apply additionalItems schema to items beyond prefixItems (if defined).
6. Validate contains with minContains/maxContains.
7. Validate items using items schema (applies to all items if prefixItems not defined, or to items beyond prefixItems if present).
8. Enforce unevaluatedItems for items not covered by prefixItems, items, contains.

Primitive validation details

Type checks

• number accepts any Java Number.
• integer accepts integral numbers (Integer, Long, etc., or decimal with zero fraction).
• null requires null value.
• any always passes.

Rule order

1. Type check first.
2. enum check next.
3. If enum exists and fails, remaining primitive constraints are not evaluated.
4. Numeric/string/format constraints run after successful type and enum checks.

Error model

• Validators return List<ValidationError>.
• ValidationResult.from(errors) marks success if list is empty.
• Each ValidationError includes:
  • nodePath
  • expectedType
  • actualType
  • description

Compact format returned to Skript expression:

[nodePath] expectedType: actualType - description

Known runtime constraints

• Data loader in Skript integration parses root as Map<String, Object>.

Related pages

• Keyword support scope: Schema keywords
• Syntax contract and path behavior: Skript API
• Practical recipes: Examples