com.fasterxml.jackson.databind.deser.std

Class JsonNodeDeserializer

    • Field Detail

      • _supportsUpdates

        protected final Boolean _supportsUpdates

    • Constructor Detail

      • JsonNodeDeserializer

        protected JsonNodeDeserializer()

    • Method Detail

      • getDeserializer

        public static JsonDeserializer<? extends JsonNode> getDeserializer(Class<?> nodeClass)
        Factory method for accessing deserializer for specific node type

      • getNullValue

        public JsonNode getNullValue(DeserializationContext ctxt)
        Description copied from class: JsonDeserializer
        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.

        Since version 2.6 (in which the context argument was added), call is expected to be made each and every time a null token needs to be handled.

        Default implementation simply returns null.

        Specified by:
        getNullValue in interface NullValueProvider
        Overrides:
        getNullValue in class JsonDeserializer<JsonNode>

      • deserialize

        public JsonNode deserialize(com.fasterxml.jackson.core.JsonParser p,
                            DeserializationContext ctxt)
                     throws IOException
        Implementation that will produce types of any JSON nodes; not just one deserializer is registered to handle (in case of more specialized handler). Overridden by typed sub-classes for more thorough checking
        Specified by:
        deserialize in class JsonDeserializer<JsonNode>
        Parameters:
        p - Parsed used for reading JSON content
        ctxt - Context that can be used to access information about this deserialization activity.
        Returns:
        Deserialized value
        Throws:
        IOException

      • isCachable

        public boolean isCachable()
        Description copied from class: JsonDeserializer
        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 resolved on per-property basis, if instance implements ResolvableDeserializer: cached instance is just as the base. 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 JsonDeserializer<T extends JsonNode>

      • supportsUpdate

        public Boolean supportsUpdate(DeserializationConfig config)
        Description copied from class: JsonDeserializer
        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 deserialization 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 JsonDeserializer<T extends JsonNode>

      • _handleDuplicateField

        protected void _handleDuplicateField(com.fasterxml.jackson.core.JsonParser p,
                                     DeserializationContext ctxt,
                                     JsonNodeFactory nodeFactory,
                                     String fieldName,
                                     ObjectNode objectNode,
                                     JsonNode oldValue,
                                     JsonNode newValue)
                              throws com.fasterxml.jackson.core.JsonProcessingException
        Method called when there is a duplicate value for a field. By default we don't care, and the last value is used. Can be overridden to provide alternate handling, such as throwing an exception, or choosing different strategy for combining values or choosing which one to keep.
        Parameters:
        fieldName - Name of the field for which duplicate value was found
        objectNode - Object node that contains values
        oldValue - Value that existed for the object node before newValue was added
        newValue - Newly added value just added to the object node
        Throws:
        com.fasterxml.jackson.core.JsonProcessingException

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