org.datavec.api.transform.serde

Class JsonMappers

java.lang.Object

org.datavec.api.transform.serde.JsonMappers

public class JsonMappers
extends Object

JSON mappers for deserializing neural net configurations, etc.

Author:

Alex Black

Field Summary

Fields

Modifier and Type	Field and Description
static String	CUSTOM_REGISTRATION_PROPERTY This system property is provided as an alternative to registerLegacyCustomClassesForJSON(Class[]) Classes can be specified in comma-separated format

Constructor Summary

Constructors

Constructor and Description
JsonMappers()

Method Summary

Modifier and Type	Method and Description
static org.nd4j.shade.jackson.databind.ObjectMapper	getLegacyMapperFor(Class<?> clazz) Get the legacy JSON mapper for the specified class. NOTE: This is intended for internal backward-compatibility use.
static org.nd4j.shade.jackson.databind.ObjectMapper	getMapper()
static org.nd4j.shade.jackson.databind.ObjectMapper	getMapperYaml()
static void	registerLegacyCustomClassesForJSON(Class<?>... classes) Register a set of classes (Transform, Filter, etc) for JSON deserialization. This is required ONLY when BOTH of the following conditions are met: 1.
static void	registerLegacyCustomClassesForJSON(List<org.nd4j.linalg.primitives.Pair<String,Class>> classes) Register a set of classes (Layer, GraphVertex, InputPreProcessor, IActivation, ILossFunction, ReconstructionDistribution ONLY) for JSON deserialization, with custom names. Using this method directly should never be required (instead: use registerLegacyCustomClassesForJSON(Class[]) but is added in case it is required in non-standard circumstances.
static void	registerLegacyCustomClassesForJSONList(List<Class<?>> classes)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CUSTOM_REGISTRATION_PROPERTY

public static String CUSTOM_REGISTRATION_PROPERTY

This system property is provided as an alternative to registerLegacyCustomClassesForJSON(Class[]) Classes can be specified in comma-separated format

Constructor Detail

JsonMappers

public JsonMappers()

Method Detail

registerLegacyCustomClassesForJSON

public static void registerLegacyCustomClassesForJSON(Class<?>... classes)

Register a set of classes (Transform, Filter, etc) for JSON deserialization.

This is required ONLY when BOTH of the following conditions are met:
1. You want to load a serialized TransformProcess, saved in 1.0.0-alpha or before, AND
2. The serialized TransformProcess has a custom Transform, Filter, etc (i.e., one not defined in DL4J)

By passing the classes of these custom classes here, DataVec should be able to deserialize them, in spite of the JSON format change between versions.

Parameters:

classes - Classes to register

registerLegacyCustomClassesForJSONList

public static void registerLegacyCustomClassesForJSONList(List<Class<?>> classes)

See Also:

registerLegacyCustomClassesForJSON(Class[])

registerLegacyCustomClassesForJSON

public static void registerLegacyCustomClassesForJSON(List<org.nd4j.linalg.primitives.Pair<String,Class>> classes)

Register a set of classes (Layer, GraphVertex, InputPreProcessor, IActivation, ILossFunction, ReconstructionDistribution ONLY) for JSON deserialization, with custom names.
Using this method directly should never be required (instead: use registerLegacyCustomClassesForJSON(Class[]) but is added in case it is required in non-standard circumstances.

getLegacyMapperFor

public static org.nd4j.shade.jackson.databind.ObjectMapper getLegacyMapperFor(@NonNull
                                                                              Class<?> clazz)

Get the legacy JSON mapper for the specified class.
NOTE: This is intended for internal backward-compatibility use. Note to developers: The following JSON mappers are for handling legacy format JSON. Note that after 1.0.0-alpha, the JSON subtype format for Transforms, Filters, Conditions etc were changed from a wrapper object, to an "@class" field. However, to not break all saved transforms networks, these mappers are part of the solution.

How legacy loading works (same pattern for all types - Transform, Filter, Condition etc)
1. Transforms etc JSON that has a "@class" field are deserialized as normal
2. Transforms JSON that don't have such a field are mapped (via Layer @JsonTypeInfo) to LegacyMappingHelper.TransformHelper
3. LegacyMappingHelper.TransformHelper has a @JsonDeserialize annotation - we use LegacyMappingHelper.LegacyTransformDeserializer to handle it
4. LegacyTransformDeserializer has a list of old names (present in the legacy format JSON) and the corresponding class names 5. BaseLegacyDeserializer (that LegacyTransformDeserializer extends) does a lookup and handles the deserialization Now, as to why we have one ObjectMapper for each type: We can't use the default JSON mapper for the legacy format, as it'll fail due to not having the expected "@class" annotation. Consequently, we need to tell Jackson to ignore that specific annotation and deserialize to the specified class anyway. The ignoring is done via an annotation introspector, defined below in this class. However, we can't just use a single annotation introspector (and hence ObjectMapper) for loading legacy values of all types - if we did, then any nested types would fail (i.e., an Condition in a Transform - the Transform couldn't be deserialized correctly, as the annotation would be ignored).

getMapper

public static org.nd4j.shade.jackson.databind.ObjectMapper getMapper()

Returns:

The default/primary ObjectMapper for deserializing JSON network configurations in DL4J

getMapperYaml

public static org.nd4j.shade.jackson.databind.ObjectMapper getMapperYaml()

Returns:

The default/primary ObjectMapper for deserializing network configurations in DL4J (YAML format)