Module tools.jackson.databind
Package tools.jackson.databind.deser.std

Class StdNodeBasedDeserializer<T>

java.lang.Object
tools.jackson.databind.ValueDeserializer<T>
tools.jackson.databind.deser.std.StdDeserializer<T>
tools.jackson.databind.deser.std.StdNodeBasedDeserializer<T>
Type Parameters:
T - Target type of this deserializer; that is, type of values that input data is deserialized into.
All Implemented Interfaces:
NullValueProvider, ValueInstantiator.Gettable
Direct Known Subclasses:
ThreadGroupDeserializer
public abstract class StdNodeBasedDeserializer<T> extends StdDeserializer<T>
Convenience deserializer that may be used to deserialize values given an intermediate tree representation (JsonNode). Note that this is a slightly simplified alternative to StdConvertingDeserializer).

  • Field Details

  • Constructor Details

  • Method Details

    • resolve

      public void resolve(DeserializationContext ctxt)
      Description copied from class: ValueDeserializer
      Method called after deserializer instance has been constructed (and registered as necessary by provider objects), but before it has returned it to the caller. Called object can then resolve its dependencies to other types, including self-references (direct or indirect).
      Overrides:
      resolve in class ValueDeserializer<T>
      Parameters:
      ctxt - Context to use for accessing configuration, resolving secondary deserializers

    • convert

      public abstract T convert(JsonNode root, DeserializationContext ctxt) throws tools.jackson.core.JacksonException
      Throws:
      tools.jackson.core.JacksonException

    • convert

      public T convert(JsonNode root, DeserializationContext ctxt, T newValue) throws tools.jackson.core.JacksonException
      Facilitates usage with ObjectMapper.readerForUpdating(Object) and deserialize(JsonParser, DeserializationContext, Object) by eliminating the need to manually convert the value to a JsonNode. If this method is not overridden, it falls back to the behavior of convert(JsonNode, DeserializationContext).
      Throws:
      tools.jackson.core.JacksonException
      Since:
      2.15

    • deserialize

      public T deserialize(tools.jackson.core.JsonParser p, DeserializationContext ctxt) throws tools.jackson.core.JacksonException
      Description copied from class: ValueDeserializer
      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).

      Handling null values (JsonToken.VALUE_NULL)
      : Note that this method is never called for the JSON null literal to avoid every deserializer from having to handle null values. Instead, the ValueDeserializer.getNullValue(DeserializationContext) method is called to produce a null value. To influence null handling, custom deserializers should override ValueDeserializer.getNullValue(DeserializationContext) and usually also ValueDeserializer.getNullAccessPattern().

      Specified by:
      deserialize in class ValueDeserializer<T>
      Parameters:
      p - Parser used for reading JSON content
      ctxt - Context that can be used to access information about this deserialization activity.
      Returns:
      Deserialized value
      Throws:
      tools.jackson.core.JacksonException

    • deserialize

      public T deserialize(tools.jackson.core.JsonParser jp, DeserializationContext ctxt, T newValue) throws tools.jackson.core.JacksonException
      Added to support convert(JsonNode, DeserializationContext, Object)
      Overrides:
      deserialize in class ValueDeserializer<T>
      Throws:
      tools.jackson.core.JacksonException
      Since:
      2.15

    • deserializeWithType

      public Object deserializeWithType(tools.jackson.core.JsonParser p, DeserializationContext ctxt, TypeDeserializer td) throws tools.jackson.core.JacksonException
      Description copied from class: StdDeserializer
      Base implementation that does not assume specific type inclusion mechanism. Sub-classes are expected to override this method if they are to handle type information.
      Overrides:
      deserializeWithType in class StdDeserializer<T>
      td - Deserializer to use for handling type information
      Throws:
      tools.jackson.core.JacksonException