AppFunctionSerializable

@Retention(value = AnnotationRetention.BINARY)
@Target(allowedTargets = [AnnotationTarget.CLASS])
public annotation AppFunctionSerializable

Annotates a class to indicate that it can be serialized and transferred between processes using AppFunction.

When a class is annotated with @AppFunctionSerializable and is used as a parameter or return type (directly or as a nested entity) in an AppFunction, the shape of the entity defined within its primary constructor will be exposed to the caller as an androidx.appfunctions.metadata.AppFunctionMetadataDocument. This information allows the caller to construct the structured input to call an AppFunction or understand what properties are provided in the structured output.

Constraints for Classes Annotated with @AppFunctionSerializable:

• Primary Constructor Parameters: Only properties declared in the primary constructor that expose a getter method are eligible for inclusion in the AppFunctionMetadata. Critically, it is a requirement to place properties with a getter in primary constructor. Attempting to include constructor parameters that are not declared as properties (and thus don't have a getter) will result in a compiler error.

• Supported Property Types: The properties in the primary constructor must be of one of the following types:

• Int

• Long

• Float

• Double

• Boolean

• String

• IntArray

• LongArray

• FloatArray

• DoubleArray

• BooleanArray

• List<String>

• Another class annotated with @AppFunctionSerializable (enabling nested structures) or a list of a class annotated with @AppFunctionSerializable

• Public Primary Constructor: The primary constructor of the annotated class must have public visibility to allow instantiation.

IMPORTANT: The default value set in the constructor parameter is ignored when the value is missing from the function calling request. Instead, the specified rule is always used:

• Non-nullable Properties: If a value is missing for a non-nullable property from the caller, the library will throw an exception to notify the caller automatically.

• Nullable Properties: If a value is missing for a nullable property, null will be used.

• Collection Properties: If a value is missing for a collection property, an empty collection will be used.

Example:

@AppFunctionSerializable
class Location(val latitude: Double, val longitude: Double)

@AppFunctionSerializable
class Place(
    val name: String,
    val location: Location, // Nested AppFunctionSerializable
    // Nullable String is allowed, if missing, will be null. The default value will not be used
    // when the value is missing
    val notes: String? = "default"
)

@AppFunctionSerializable
class SearchPlaceResult(
    val places: List<Place> // If missing, will be an empty list
)

@AppFunctionSerializable
class Attachment(
  uri: String // Putting constructor parameter without getter will result in compiler error
)

Summary

public AppFunctionSerializable()