Package arez.annotations

Annotation Interface AutoObserve

@Documented
@Target({METHOD,FIELD})
public @interface AutoObserve

Methods and fields annotated by this annotation should be observed for the alive lifetime of the component.

This annotation is typically used when a field references an ArezComponent annotated class that has ArezComponent.disposeOnDeactivate() set to true. This results in the current component observing the referenced component and thus preventing it from being disposed for the lifetime of the current component.

It should be noted that it is preferable for the field that defines the observed component to be marked with this annotation rather than the method accessor. The reason is that the annotation processor will issue a warning if a field that the processor identifies as a potential dependency if it is not annotated with AutoObserve, CascadeDispose or ComponentDependency.

If the element annotated is a method then the method must comply with the additional constraints:

• Must not be annotated with any other arez annotation other than Reference or Observable
• Must have 0 parameters
• Must return a value compatible with ComponentObservable, unless validateTypeAtRuntime() is true
• Must not be private
• Must not be static
• Must not be abstract unless the method is annotated with Reference or Observable in which case it MUST be abstract
• Must not throw exceptions
• Must be accessible to the class annotated by the ArezComponent annotation.

If the element annotated is a field then the field must comply with the additional constraints:

• Must be final
• Must not be private
• Must not be static
• Must be compatible with ComponentObservable, unless validateTypeAtRuntime() is true
• Must be accessible to the class annotated by the ArezComponent annotation.
• Should not be public. A warning will be generated but can be suppressed by the SuppressWarnings or SuppressArezWarnings annotations with a key "Arez:PublicField".
• Should not be protected if in the class annotated with the ArezComponent annotation as the field is not expected to be accessed outside the component. A warning will be generated but can be suppressed by the SuppressWarnings or SuppressArezWarnings annotations with a key "Arez:ProtectedField".

If validateTypeAtRuntime() is set to true then the declared type of the field or method must be annotated with ArezComponentLike. In this mode, type compatibility is validated at runtime rather than compile time while still treating the declared type as component-like for validation only.

This annotation is only supported on elements contained within a type annotated by ArezComponent or ArezComponentLike. Other usages will fail compilation.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
boolean	validateTypeAtRuntime	Return true and the value of the annotated field or method will be validated at runtime rather than compile time.

Element Details

validateTypeAtRuntime

boolean validateTypeAtRuntime

Return true and the value of the annotated field or method will be validated at runtime rather than compile time. This is useful when the declared type is annotated with ArezComponentLike but the runtime value is known to implement ComponentObservable.

Returns:

true to defer validation of types until runtime.

Default:

false