public abstract Class ReferenceTypeDeserializer<T>

Overrides tools.jackson.databind.ValueDeserializer.createContextual.

Doc from tools.jackson.databind.ValueDeserializer.createContextual.

Method called to see if a different (or differently configured) deserializer is needed to deserialize values of specified property. Note that instance that this method is called on is typically shared one and as a result method should NOT modify this instance but rather construct and return a new instance. This instance should only be returned as-is, in case it is already suitable for use.

Annotations

@Override

Implements abstract tools.jackson.databind.ValueDeserializer.deserialize.

Doc from tools.jackson.databind.ValueDeserializer.deserialize.

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",
          ...
      }
  

       if (p.currentToken() == JsonToken.START_OBJECT) {
         p.nextToken();
       }
  

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().

Annotations

@Override

Overrides tools.jackson.databind.ValueDeserializer.deserialize.

Doc from tools.jackson.databind.ValueDeserializer.deserialize.

Alternate deserialization method (compared to the most commonly used, 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)

Annotations

@Override

Overrides tools.jackson.databind.deser.std.StdDeserializer.deserializeWithType.

Doc from tools.jackson.databind.deser.std.StdDeserializer.deserializeWithType.

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.

Annotations

@Override

Overrides tools.jackson.databind.ValueDeserializer.getAbsentValue.

Overrides default tools.jackson.databind.deser.NullValueProvider.getAbsentValue.

Doc from tools.jackson.databind.ValueDeserializer.getAbsentValue.

Method called to determine placeholder value to be used for cases where no value was obtained from input but we must pass a value nonetheless: the common case is that of Creator methods requiring passing a value for every parameter. Usually this is same as getNullValue (which in turn is usually simply Java null), but it can be overridden for specific types: most notable scalar types must use "default" values.

This method needs to be called every time a determination is made.

Default implementation simply calls getNullValue and returns value.

Annotations

@Override

Overrides tools.jackson.databind.ValueDeserializer.getEmptyAccessPattern.

Doc from tools.jackson.databind.ValueDeserializer.getEmptyAccessPattern.

This method may be called in conjunction with calls to getEmptyValue(DeserializationContext), to check whether it needs to be called just once (static values), or each time empty value is needed.

Annotations

@Override

Overrides tools.jackson.databind.ValueDeserializer.getEmptyValue.

Doc from tools.jackson.databind.ValueDeserializer.getEmptyValue.

Method called to determine value to be used for "empty" values (most commonly when deserializing from empty JSON Strings). Usually this is same as getNullValue (which in turn is usually simply Java null), but it can be overridden for specific types. Or, if type should never be converted from empty String, method can also throw an exception.

This method may be called once, or multiple times, depending on what getEmptyAccessPattern() returns.

Default implementation simply calls getNullValue and returns value.

Annotations

@Override

Overrides tools.jackson.databind.ValueDeserializer.getNullAccessPattern.

Implements tools.jackson.databind.deser.NullValueProvider.getNullAccessPattern.

Null value varies dynamically (unlike with scalar types), so let's indicate this.

Annotations

@Override

Redeclares tools.jackson.databind.deser.NullValueProvider.getNullValue.

Overrides tools.jackson.databind.ValueDeserializer.getNullValue.

Doc from tools.jackson.databind.ValueDeserializer.getNullValue.

Method that can be called to determine value to be used for representing null values (values deserialized when JSON token is JsonToken#VALUE_NULL). Usually this is simply Java null, but for some types (especially primitives) it may be necessary to use non-null values.

This method may be called once, or multiple times, depending on what getNullAccessPattern() returns.

Default implementation simply returns null.

Annotations

@Override

Method that may be called to find contents of specified reference, if any; or `null` if none. Note that method should never fail, so for types that use concept of "absence" vs "presence", `null` is to be returned for both "absent" and "reference to `null`" cases.

Overrides tools.jackson.databind.deser.std.StdDeserializer.getValueInstantiator.

Implements tools.jackson.databind.deser.ValueInstantiator.Gettable.getValueInstantiator.

Annotations

@Override

Overrides tools.jackson.databind.deser.std.StdDeserializer.getValueType.

Doc from tools.jackson.databind.deser.std.StdDeserializer.getValueType.

Exact structured type this deserializer handles, if known.

Annotations

@Override

Overrides tools.jackson.databind.ValueDeserializer.logicalType.

Doc from tools.jackson.databind.ValueDeserializer.logicalType.

Method for accessing logical type of values this deserializer produces. Typically used for further configuring handling of values, for example, to find which coercions are legal.

Annotations

@Override

Overrides tools.jackson.databind.ValueDeserializer.supportsUpdate.

By default we assume that updateability mostly relies on value deserializer; if it supports updates, typically that's what matters. So let's just delegate.

Annotations

@Override

Method called in case of "merging update", in which we should try update reference instead of creating a new one. If this does not succeed, should just create a new instance.