com.fasterxml.jackson.databind.jsontype

Interface TypeIdResolver

All Known Implementing Classes:

ClassNameIdResolver, MinimalClassNameIdResolver, TypeIdResolverBase, TypeNameIdResolver

public interface TypeIdResolver

Interface that defines standard API for converting types to type identifiers and vice versa. Used by type resolvers (TypeSerializer, TypeDeserializer) for converting between type and matching id; id is stored in JSON and needed for creating instances of proper subtypes when deserializing values.

NOTE: it is strongly recommended that developers always extend abstract base class TypeIdResolverBase instead of directly implementing this interface; this helps prevent breakage in case new methds need to be added in this interface (something we try to avoid doing; but which may be necessary in some cases).

Method Summary

Modifier and Type	Method and Description
String	getDescForKnownTypeIds() Method called for error-reporting and diagnostics purposes.
JsonTypeInfo.Id	getMechanism() Accessor for mechanism that this resolver uses for determining type id from type.
String	idFromBaseType() Method that can be called to figure out type id to use for instances of base type (declared type of property).
String	idFromValue(Object value) Method called to serialize type of the type of given value as a String to include in serialized JSON content.
String	idFromValueAndType(Object value, Class<?> suggestedType) Alternative method used for determining type from combination of value and type, using suggested type (that serializer provides) and possibly value of that type.
void	init(JavaType baseType) Method that will be called once before any type resolution calls; used to initialize instance with configuration.
JavaType	typeFromId(DatabindContext context, String id) Method called to resolve type from given type identifier.

Method Detail

init

void init(JavaType baseType)

Method that will be called once before any type resolution calls; used to initialize instance with configuration. This is necessary since instances may be created via reflection, without ability to call specific constructor to pass in configuration settings.

Parameters:

baseType - Base type for which this id resolver instance is used

idFromValue

String idFromValue(Object value)

Method called to serialize type of the type of given value as a String to include in serialized JSON content.

idFromValueAndType

String idFromValueAndType(Object value,
                          Class<?> suggestedType)

Alternative method used for determining type from combination of value and type, using suggested type (that serializer provides) and possibly value of that type. Most common implementation will use suggested type as is.

idFromBaseType

String idFromBaseType()

Method that can be called to figure out type id to use for instances of base type (declared type of property). This is usually only used for fallback handling, for cases where real type information is not available for some reason.

typeFromId

JavaType typeFromId(DatabindContext context,
                    String id)
             throws IOException

Method called to resolve type from given type identifier.

Throws:

IOException

Since:

2.5 (throws clause added in 2.8)

getDescForKnownTypeIds

String getDescForKnownTypeIds()

Method called for error-reporting and diagnostics purposes.

Since:

2.7 -- but since 2.5 has existed in TypeIdResolverBase

getMechanism

JsonTypeInfo.Id getMechanism()

Accessor for mechanism that this resolver uses for determining type id from type. Mostly informational; not required to be called or used.