com.fasterxml.jackson.databind.deser.impl

Class FailingDeserializer

java.lang.Object

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

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

com.fasterxml.jackson.databind.deser.impl.FailingDeserializer

All Implemented Interfaces:

Serializable

public class FailingDeserializer
extends StdDeserializer<Object>

Special bogus "serializer" that will throw JsonMappingException if an attempt is made to deserialize a value. This is used as placeholder to avoid NPEs for uninitialized structured serializers or handlers.

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 String	_message

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

_valueClass

Constructor Summary

Constructors

Constructor and Description
FailingDeserializer(String m)

Method Summary

Methods

Modifier and Type	Method and Description
Object	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.

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

_hasTextualNull, _isNaN, _isNegInf, _isPosInf, _parseBoolean, _parseBooleanFromNumber, _parseBooleanPrimitive, _parseByte, _parseDate, _parseDouble, _parseDoublePrimitive, _parseFloat, _parseFloatPrimitive, _parseInteger, _parseIntPrimitive, _parseLong, _parseLongPrimitive, _parseShort, _parseShortPrimitive, _parseString, deserializeWithType, 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, isCachable, replaceDelegatee, unwrappingDeserializer

Methods inherited from class java.lang.Object

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

Field Detail

_message

protected final String _message

Constructor Detail

FailingDeserializer

public FailingDeserializer(String m)

Method Detail

deserialize

public Object deserialize(com.fasterxml.jackson.core.JsonParser jp,
                 DeserializationContext ctxt)
                   throws JsonMappingException

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:

JsonMappingException