javax.json.bind.adapter.JsonbAdapter Maven / Gradle / Ivy
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package javax.json.bind.adapter;
/**
* Allows to define custom mapping for given java type. The target type could be string or some
* mappable java type.
*
* On serialization "Original" type is converted into "Adapted" type. After that "Adapted" type is serialized to
* JSON the standard way.
*
* On deserialization it works the reverse way: JSON data are deserialized into "Adapted" type which is converted
* to "Original" type after that.
*
* Adapters are registered using {@link javax.json.bind.JsonbConfig#withAdapters(JsonbAdapter[])} method
* or using {@link javax.json.bind.annotation.JsonbTypeAdapter} annotation on class field.
*
* @param The type that JSONB doesn't know how to handle
* @param The type that JSONB knows how to handle out of the box
*
* Adapter runtime "Original" and "Adapted" generic types are inferred from subclassing information,
* which is mandatory for adapter to work.
*
* Sample 1:
*
* {@code
* // Generic information is provided by subclassing.
* class BoxToCrateAdapter implements JsonbAdapter, Crate> {...};
* jsonbConfig.withAdapters(new BoxToCrateAdapter());
*
* // Generic information is provided by subclassing with anonymous class
* jsonbConfig.withAdapters(new JsonbAdapter, Crate> {...});
* }
*
*
* Sample 2:
*
* {@code
* BoxToCrateAdapter implements JsonbAdapter, Integer> {...};
*
* // Bad way: Generic type information is lost due to type erasure
* jsonbConfig.withAdapters(new BoxToCrateAdapter());
*
* // Proper way: Anonymous class holds generic type information
* jsonbConfig.withAdapters(new BoxToCrateAdapter(){});
* }
*
*
* @see javax.json.bind.JsonbConfig
* @see javax.json.bind.annotation.JsonbTypeAdapter
* @since JSON Binding 1.0
*/
public interface JsonbAdapter {
/**
* This method is used on serialization only. It contains a conversion logic from type Original to type Adapted.
* After conversion Adapted type will be mapped to JSON the standard way.
*
* @param obj
* Object to convert.
* @return Converted object which will be serialized to JSON.
* @throws Exception if there is an error during the conversion.
*/
Adapted adaptToJson(Original obj) throws Exception;
/**
* This method is used on deserialization only. It contains a conversion logic from type Adapted to type Original.
*
* @param obj
* Object to convert.
* @return Converted object representing pojo to be set into object graph.
* @throws Exception if there is an error during the conversion.
*/
Original adaptFromJson(Adapted obj) throws Exception;
}