com.lightbend.lagom.serialization

Class JacksonJsonMigration

Object

com.lightbend.lagom.serialization.JacksonJsonMigration

public abstract class JacksonJsonMigration
extends Object

Data migration of old formats to current format can be implemented in a concrete subclass and configured to be used by the JacksonJsonSerializer for a changed class.

It is used when deserializing data of older version than the currentVersion(). You implement the transformation of the JSON structure in the transform(int, com.fasterxml.jackson.databind.JsonNode) method. If you have changed the class name you should override transformClassName(int, java.lang.String) and return current class name.

Constructor Summary

Constructors

Constructor and Description
JacksonJsonMigration()

Method Summary

Modifier and Type	Method and Description
abstract int	currentVersion() Define current version.
abstract com.fasterxml.jackson.databind.JsonNode	transform(int fromVersion, com.fasterxml.jackson.databind.JsonNode json) Implement the transformation of the old JSON structure to the new JSON structure.
String	transformClassName(int fromVersion, String className) Override this method if you have changed the class name.

Methods inherited from class Object

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

Constructor Detail

JacksonJsonMigration

public JacksonJsonMigration()

Method Detail

currentVersion

public abstract int currentVersion()

Define current version. The first version, when no migration was used, is always 1.

transform

public abstract com.fasterxml.jackson.databind.JsonNode transform(int fromVersion,
                                                                  com.fasterxml.jackson.databind.JsonNode json)

Implement the transformation of the old JSON structure to the new JSON structure. The JsonNode is mutable so you can add and remove fields, or change values. Note that you have to cast to specific sub-classes such as ObjectNode and ArrayNode to get access to mutators.

Parameters:

fromVersion - the version of the old data

json - the old JSON data

transformClassName

public String transformClassName(int fromVersion,
                                 String className)

Override this method if you have changed the class name. Return current class name.