react4j.annotations

Annotation Type Callback

@Documented
 @Target(value=METHOD)
public @interface Callback

Annotation used to specify a callback passed to react components. This annotation used to generate a callback accessor method in the helper class. The callback accessor method will return the same callback instance each time it is called, making this ideal for use in "PureComponent" style components. If the callback is annotated with JsFunction then the code gives the callback a user friendly name for debugging. The code for specifying the friendly name will be optimized away when ReactConfig.enableComponentNames() returns false. Using JsFunction also reduces the generated code size.

Using this annotation and the corresponding helper method is entirely optional but does provide some value when building components that you want to easily interact with from the React DevTools or building a component that compares props values to determine whether it needs to re-render.

The method that is annotated with this annotation must also comply with the following constraints:

• Must not be annotated with any other react annotation
• Must not be an abstract instance method
• Must not throw exceptions
• Must be accessible from the same package as the class annotated by ReactComponent
• Must have 0 parameters or the same set of parameters as the callback type
• Must return a value of the same type as the callback type if any

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
Feature	initCallbackContext The flag indicates whether the annotation processor should manage the calling context.
java.lang.String	name Return the name of the callback.
java.lang.Class	value The type of the callback.

Element Detail

name

@Nonnull
public abstract java.lang.String name

Return the name of the callback. The value defaults to the name of the method. The value must conform to the requirements of a java identifier and be unique across the component.

Returns:

the name of the callback.

Default:

"<default>"

value

public abstract java.lang.Class value

The type of the callback. The type should be an interface and the interface should be annotated with JsFunction to ensure that the method can be given a useful debug name.

Returns:

the type of the callback.

Default:

react4j.annotations.Callback.Procedure.class

initCallbackContext

public abstract Feature initCallbackContext

The flag indicates whether the annotation processor should manage the calling context. if set to Feature.ENABLE then caller context will be setup. In practical terms this means that subclasses of ReactArezComponent will have the callback annotated with an arez.annotations.Action annotation. if set to Feature.DISABLE then the code that invokes the callback is responsible for setting up the calling context. This is typically used when you are passing a "render" prop into a component that invokes the callback to render react4j.ReactNode. The Feature.AUTODETECT value will detect whether the component needs calling context setup and do so if necessary. At the moment this means that subclasses of ReactArezComponent are enabled.

Returns:

the flag to control calling context.

Default:

react4j.annotations.Feature.AUTODETECT