public Class NullifyingDeserializer

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.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.supportsUpdate.

Doc from tools.jackson.databind.ValueDeserializer.supportsUpdate.

Introspection method that may be called to see whether deserializer supports update of an existing value (aka "merging") or not. Return value should either be Boolean#FALSE if update is not supported at all (immutable values); Boolean#TRUE if update should usually work (regular POJOs, for example), or null if this is either not known, or may sometimes work.

Information gathered is typically used to either prevent merging update for property (either by skipping, if based on global defaults; or by exception during deserializer construction if explicit attempt made) if Boolean#FALSE returned, or inclusion if Boolean#TRUE is specified. If "unknown" case (null returned) behavior is to exclude property if global defaults used; or to allow if explicit per-type or property merging is defined.

Default implementation returns null to allow explicit per-type or per-property attempts.

Annotations

@Override