Module tools.jackson.databind
Package tools.jackson.databind.deser.jdk

Class UntypedObjectDeserializer

java.lang.Object
tools.jackson.databind.ValueDeserializer<T>
tools.jackson.databind.deser.std.StdDeserializer<Object>
tools.jackson.databind.deser.jdk.UntypedObjectDeserializer
All Implemented Interfaces:
NullValueProvider, ValueInstantiator.Gettable
public class UntypedObjectDeserializer extends StdDeserializer<Object>
Deserializer implementation that is used if it is necessary to bind content of "unknown" type; something declared as basic Object (either explicitly, or due to type erasure). If so, "natural" mapping is used to convert JSON values to their natural Java object matches: JSON arrays to Java Lists (or, if configured, Object[]), JSON objects to Maps, numbers to Numbers, booleans to Booleans and strings to String (and nulls to nulls).

  • Field Details

    • NO_OBJECTS

      protected static final Object[] NO_OBJECTS

    • _mapDeserializer

      protected ValueDeserializer<Object> _mapDeserializer

    • _listDeserializer

      protected ValueDeserializer<Object> _listDeserializer

    • _stringDeserializer

      protected ValueDeserializer<Object> _stringDeserializer

    • _numberDeserializer

      protected ValueDeserializer<Object> _numberDeserializer

    • _listType

      protected JavaType _listType
      If List has been mapped to non-default implementation, we'll store type here
      Since:
      2.6

    • _mapType

      protected JavaType _mapType
      If Map has been mapped to non-default implementation, we'll store type here

    • _nonMerging

      protected final boolean _nonMerging

  • Constructor Details

  • Method Details

    • resolve

      public void resolve(DeserializationContext ctxt)
      We need to implement this method to properly find things to delegate to: it cannot be done earlier since delegated deserializers almost certainly require access to this instance (at least "List" and "Map" ones)
      Overrides:
      resolve in class ValueDeserializer<Object>
      Parameters:
      ctxt - Context to use for accessing configuration, resolving secondary deserializers

    • _findCustomDeser

      protected ValueDeserializer<Object> _findCustomDeser(DeserializationContext ctxt, JavaType type)

    • _clearIfStdImpl

      protected ValueDeserializer<Object> _clearIfStdImpl(ValueDeserializer<Object> deser)

    • createContextual

      public ValueDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property)
      We only use contextualization for optimizing the case where no customization occurred; if so, can slip in a more streamlined version.
      Overrides:
      createContextual in class ValueDeserializer<Object>
      Parameters:
      ctxt - Deserialization context to access configuration, additional deserializers that may be needed by this deserializer
      property - Method, field or constructor parameter that represents the property (and is used to assign deserialized value). Should be available; but there may be cases where caller cannot provide it and null is passed instead (in which case impls usually pass 'this' deserializer as is)
      Returns:
      Deserializer to use for deserializing values of specified property; may be this instance or a new instance.

    • isCachable

      public boolean isCachable()
      Description copied from class: ValueDeserializer
      Method called to see if deserializer instance is cachable and usable for other properties of same type (type for which instance was created).

      Note that cached instances are still contextualized on per-property basis (but note that ValueDeserializer.resolve(DeserializationContext)d just once!) This means that in most cases it is safe to cache instances; however, it only makes sense to cache instances if instantiation is expensive, or if instances are heavy-weight.

      Default implementation returns false, to indicate that no caching is done.

      Overrides:
      isCachable in class ValueDeserializer<Object>

    • logicalType

      public LogicalType logicalType()
      Description copied from class: ValueDeserializer
      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.
      Overrides:
      logicalType in class ValueDeserializer<Object>
      Returns:
      Logical type of values this deserializer produces, if known; null if not

    • supportsUpdate

      public Boolean supportsUpdate(DeserializationConfig config)
      Description copied from class: ValueDeserializer
      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.

      Overrides:
      supportsUpdate in class ValueDeserializer<Object>

    • deserialize

      public Object deserialize(JsonParser p, DeserializationContext ctxt) throws 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<Object>
      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:
      JacksonException

    • deserializeWithType

      public Object deserializeWithType(JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer) throws 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<Object>
      typeDeserializer - Deserializer to use for handling type information
      Throws:
      JacksonException

    • deserialize

      public Object deserialize(JsonParser p, DeserializationContext ctxt, Object intoValue) throws JacksonException
      Description copied from class: ValueDeserializer
      Alternate deserialization method (compared to the most commonly used, ValueDeserializer.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)

      Overrides:
      deserialize in class ValueDeserializer<Object>
      Throws:
      JacksonException

    • mapArray

      protected Object mapArray(JsonParser p, DeserializationContext ctxt) throws JacksonException
      Method called to map a JSON Array into a Java value.
      Throws:
      JacksonException

    • mapArray

      protected Object mapArray(JsonParser p, DeserializationContext ctxt, Collection<Object> result) throws JacksonException
      Throws:
      JacksonException

    • mapObject

      protected Object mapObject(JsonParser p, DeserializationContext ctxt) throws JacksonException
      Method called to map a JSON Object into a Java value.
      Throws:
      JacksonException

    • _mapObjectWithDups

      protected Object _mapObjectWithDups(JsonParser p, DeserializationContext ctxt, Map<String,Object> result, String key, Object oldValue, Object newValue, String nextKey) throws JacksonException
      Throws:
      JacksonException

    • mapArrayToArray

      protected Object[] mapArrayToArray(JsonParser p, DeserializationContext ctxt) throws JacksonException
      Method called to map a JSON Array into a Java Object array (Object[]).
      Throws:
      JacksonException

    • mapObject

      protected Object mapObject(JsonParser p, DeserializationContext ctxt, Map<Object,Object> m) throws JacksonException
      Throws:
      JacksonException

    • _deserializeFP

      protected Object _deserializeFP(JsonParser p, DeserializationContext ctxt) throws JacksonException
      Throws:
      JacksonException