com.fasterxml.jackson.databind.deser.impl

Class ErrorThrowingDeserializer

java.lang.Object

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

com.fasterxml.jackson.databind.deser.impl.ErrorThrowingDeserializer

All Implemented Interfaces:

NullValueProvider

public class ErrorThrowingDeserializer
extends JsonDeserializer<Object>

A deserializer that stores an Error caught during constructing of the deserializer, which needs to be deferred and only during actual attempt to deserialize a value of given type. Note that null and empty values can be deserialized without error.

Since:

2.9 Note: prior to this version was named NoClassDefFoundDeserializer

Nested Class Summary

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

JsonDeserializer.None

Constructor Summary

Constructors

Constructor and Description
ErrorThrowingDeserializer(NoClassDefFoundError cause)

Method Summary

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.JsonDeserializer

deserialize, deserializeWithType, deserializeWithType, findBackReference, getAbsentValue, getDelegatee, getEmptyAccessPattern, getEmptyValue, getEmptyValue, getKnownPropertyNames, getNullAccessPattern, getNullValue, getNullValue, getObjectIdReader, handledType, isCachable, logicalType, replaceDelegatee, supportsUpdate, unwrappingDeserializer

Methods inherited from class java.lang.Object

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

Constructor Detail

ErrorThrowingDeserializer

public ErrorThrowingDeserializer(NoClassDefFoundError cause)

Method Detail

deserialize

public Object 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 (p.currentToken() == JsonToken.START_OBJECT) {
         p.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