com.fasterxml.jackson.databind.deser.impl

Class TypeWrappedDeserializer

java.lang.Object

com.fasterxml.jackson.databind.JsonDeserializer<Object>

com.fasterxml.jackson.databind.deser.impl.TypeWrappedDeserializer

All Implemented Interfaces:

Serializable

public final class TypeWrappedDeserializer
extends JsonDeserializer<Object>
implements Serializable

Simple deserializer that will call configured type deserializer, passing in configured data deserializer, and exposing it all as a simple deserializer. This is necessary when there is no "parent" deserializer which could handle details of calling a TypeDeserializer, most commonly used with root values.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.fasterxml.jackson.databind.JsonDeserializer

JsonDeserializer.None

Field Summary

Fields

Modifier and Type	Field and Description
protected JsonDeserializer<Object>	_deserializer
protected TypeDeserializer	_typeDeserializer

Constructor Summary

Constructors

Constructor and Description
TypeWrappedDeserializer(TypeDeserializer typeDeser, JsonDeserializer<?> deser)

Method Summary

Modifier and Type	Method and Description
Object	deserialize(JsonParser jp, DeserializationContext ctxt) Method that can be called to ask implementation to deserialize JSON content into the value type this serializer handles.
Object	deserialize(JsonParser jp, DeserializationContext ctxt, Object intoValue) Alternate deserialization method (compared to the most commonly used, JsonDeserializer.deserialize(JsonParser, DeserializationContext)), which takes in initialized value instance, to be configured and/or populated by deserializer.
Object	deserializeWithType(JsonParser jp, DeserializationContext ctxt, TypeDeserializer typeDeserializer) Deserialization called when type being deserialized is defined to contain additional type identifier, to allow for correctly instantiating correct subtype.
Class<?>	handledType() Method for accessing type of values this deserializer produces.

Methods inherited from class com.fasterxml.jackson.databind.JsonDeserializer

findBackReference, getDelegatee, getEmptyValue, getKnownPropertyNames, getNullValue, getObjectIdReader, isCachable, replaceDelegatee, unwrappingDeserializer

Methods inherited from class java.lang.Object

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

Field Detail

_typeDeserializer

protected final TypeDeserializer _typeDeserializer

_deserializer

protected final JsonDeserializer<Object> _deserializer

Constructor Detail

TypeWrappedDeserializer

public TypeWrappedDeserializer(TypeDeserializer typeDeser,
                               JsonDeserializer<?> deser)

Method Detail

handledType

public Class<?> handledType()

Description copied from class: JsonDeserializer

Method for accessing type of values this deserializer produces. Note that this information is not guaranteed to be exact -- it may be a more generic (super-type) -- but it should not be incorrect (return a non-related type).

Default implementation will return null, which means almost same same as returning Object.class would; that is, that nothing is known about handled type.

Overrides:

handledType in class JsonDeserializer<Object>

deserialize

public Object deserialize(JsonParser jp,
                          DeserializationContext ctxt)
                   throws IOException

Description copied from class: JsonDeserializer

Method that can be called to ask implementation to deserialize JSON content into the value type this serializer handles. Returned instance is to be constructed by method itself.

Pre-condition for this method is that the parser points to the first event that is part of value to deserializer (and which is never JSON 'null' literal, more on this below): for simple types it may be the only value; and for structured types the Object start marker or a FIELD_NAME.

The two possible input conditions for structured types result from polymorphism via fields. In the ordinary case, Jackson calls this method when it has encountered an OBJECT_START, and the method implementation must advance to the next token to see the first field name. If the application configures polymorphism via a field, then the object looks like the following.

      {
          "@class": "class name",
          ...
      }
  

Jackson consumes the two tokens (the @class field name and its value) in order to learn the class and select the deserializer. Thus, the stream is pointing to the FIELD_NAME for the first field after the @class. Thus, if you want your method to work correctly both with and without polymorphism, you must begin your method with:

       if (jp.getCurrentToken() == JsonToken.START_OBJECT) {
         jp.nextToken();
       }
  

This results in the stream pointing to the field name, so that the two conditions align.

Post-condition is that the parser will point to the last event that is part of deserialized value (or in case deserialization fails, event that was not recognized or usable, which may be the same event as the one it pointed to upon call).

Note that this method is never called for JSON null literal, and thus deserializers need (and should) not check for it.

Specified by:

deserialize in class JsonDeserializer<Object>

Parameters:

jp - Parsed used for reading JSON content

ctxt - Context that can be used to access information about this deserialization activity.

Returns:

Deserialized value

Throws:

IOException

deserializeWithType

public Object deserializeWithType(JsonParser jp,
                                  DeserializationContext ctxt,
                                  TypeDeserializer typeDeserializer)
                           throws IOException

Description copied from class: JsonDeserializer

Deserialization called when type being deserialized is defined to contain additional type identifier, to allow for correctly instantiating correct subtype. This can be due to annotation on type (or its supertype), or due to global settings without annotations.

Default implementation may work for some types, but ideally subclasses should not rely on current default implementation. Implementation is mostly provided to avoid compilation errors with older code.

Overrides:

deserializeWithType in class JsonDeserializer<Object>

typeDeserializer - Deserializer to use for handling type information

Throws:

IOException

deserialize

public Object deserialize(JsonParser jp,
                          DeserializationContext ctxt,
                          Object intoValue)
                   throws IOException

Description copied from class: JsonDeserializer

Alternate deserialization method (compared to the most commonly used, JsonDeserializer.deserialize(JsonParser, DeserializationContext)), which takes in initialized value instance, to be configured and/or populated by deserializer. Method is not necessarily used (or supported) by all types (it will not work for immutable types, for obvious reasons): most commonly it is used for Collections and Maps. It may be used both with "updating readers" (for POJOs) and when Collections and Maps use "getter as setter".

Default implementation just throws UnsupportedOperationException, to indicate that types that do not explicitly add support do not necessarily support update-existing-value operation (esp. immutable types)

Overrides:

deserialize in class JsonDeserializer<Object>

Throws:

IOException