com.fasterxml.jackson.databind.deser.std

Class EnumDeserializer

java.lang.Object

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

com.fasterxml.jackson.databind.deser.std.StdDeserializer<T>

com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer<Enum<?>>

com.fasterxml.jackson.databind.deser.std.EnumDeserializer

All Implemented Interfaces:

Serializable

public class EnumDeserializer
extends StdScalarDeserializer<Enum<?>>

Deserializer class that can deserialize instances of specified Enum class from Strings and Integers.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	EnumDeserializer.FactoryBasedDeserializer Deserializer that uses a single-String static factory method for locating Enum values by String id.

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

JsonDeserializer.None

Field Summary

Fields

Modifier and Type	Field and Description
protected EnumResolver<?>	_resolver

Fields inherited from class com.fasterxml.jackson.databind.deser.std.StdDeserializer

_valueClass

Constructor Summary

Constructors

Constructor and Description
EnumDeserializer(EnumResolver<?> res)

Method Summary

Methods

Modifier and Type	Method and Description
Enum<?>	deserialize(com.fasterxml.jackson.core.JsonParser jp, DeserializationContext ctxt) Method that can be called to ask implementation to deserialize JSON content into the value type this serializer handles.
static JsonDeserializer<?>	deserializerForCreator(DeserializationConfig config, Class<?> enumClass, AnnotatedMethod factory) Factory method used when Enum instances are to be deserialized using a creator (static factory method)
boolean	isCachable() Because of costs associated with constructing Enum resolvers, let's cache instances by default.

Methods inherited from class com.fasterxml.jackson.databind.deser.std.StdScalarDeserializer

deserializeWithType

Methods inherited from class com.fasterxml.jackson.databind.deser.std.StdDeserializer

_deserializeFromEmpty, _hasTextualNull, _isNaN, _isNegInf, _isPosInf, _parseBoolean, _parseBooleanFromNumber, _parseBooleanPrimitive, _parseByte, _parseDate, _parseDouble, _parseDoublePrimitive, _parseFloat, _parseFloatPrimitive, _parseInteger, _parseIntPrimitive, _parseLong, _parseLongPrimitive, _parseShort, _parseShortPrimitive, _parseString, findConvertingContentDeserializer, findDeserializer, getValueClass, getValueType, handledType, handleUnknownProperty, isDefaultDeserializer, isDefaultKeyDeserializer, parseDouble

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

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

Methods inherited from class java.lang.Object

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

Field Detail

_resolver

protected final EnumResolver<?> _resolver

Constructor Detail

EnumDeserializer

public EnumDeserializer(EnumResolver<?> res)

Method Detail

deserializerForCreator

public static JsonDeserializer<?> deserializerForCreator(DeserializationConfig config,
                                         Class<?> enumClass,
                                         AnnotatedMethod factory)

Factory method used when Enum instances are to be deserialized using a creator (static factory method)

Returns:

Deserializer based on given factory method, if type was suitable; null if type can not be used

isCachable

public boolean isCachable()

Because of costs associated with constructing Enum resolvers, let's cache instances by default.

Overrides:

isCachable in class JsonDeserializer<Enum<?>>

deserialize

public Enum<?> deserialize(com.fasterxml.jackson.core.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<Enum<?>>

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