Package com.fasterxml.jackson.databind.ext

Class CoreXMLDeserializers.Std

  • All Implemented Interfaces:
    NullValueProvider, ValueInstantiator.Gettable, java.io.Serializable
    Enclosing class:
    CoreXMLDeserializers
    public static class CoreXMLDeserializers.Std
extends FromStringDeserializer<java.lang.Object>
    Combo-deserializer that supports deserialization of somewhat optional javax.xml types QName, Duration and XMLGregorianCalendar. Combined into a single class to eliminate bunch of one-off implementation classes, to reduce resulting jar size (mostly).
    Since:
    2.4
    See Also:
    Serialized Form

    • Constructor Detail

      • Std

        public Std​(java.lang.Class<?> raw,
           int kind)

    • Method Detail

      • deserialize

        public java.lang.Object deserialize​(JsonParser p,
                                    DeserializationContext ctxt)
                             throws java.io.IOException
        Description copied from class: JsonDeserializer
        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).

        Note that this method is never called for JSON null literal, and thus deserializers need (and should) not check for it.

        Overrides:
        deserialize in class FromStringDeserializer<java.lang.Object>
        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:
        java.io.IOException