Module tools.jackson.databind
Package tools.jackson.databind.deser.std

Class FromStringDeserializer<T>

java.lang.Object
tools.jackson.databind.ValueDeserializer<T>
tools.jackson.databind.deser.std.StdDeserializer<T>
tools.jackson.databind.deser.std.StdScalarDeserializer<T>
tools.jackson.databind.deser.std.FromStringDeserializer<T>
All Implemented Interfaces:
NullValueProvider, ValueInstantiator.Gettable
Direct Known Subclasses:
CoreXMLDeserializers.Std, DOMDeserializer, JDKFromStringDeserializer, UUIDDeserializer
public abstract class FromStringDeserializer<T> extends StdScalarDeserializer<T>
Base class for building simple scalar value deserializers that accept String values.

  • Constructor Details

    • FromStringDeserializer

      protected FromStringDeserializer(Class<?> vc)

    • FromStringDeserializer

      protected FromStringDeserializer(JavaType type)

  • Method Details

    • 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 StdScalarDeserializer<T>
      Returns:
      Logical type of values this deserializer produces, if known; null if not

    • deserialize

      public T 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<T>
      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

    • _deserialize

      protected abstract T _deserialize(String value, DeserializationContext ctxt) throws JacksonException, MalformedURLException, UnknownHostException
      Main method from trying to deserialize actual value from non-empty String.
      Throws:
      JacksonException
      MalformedURLException
      UnknownHostException

    • _shouldTrim

      protected boolean _shouldTrim()

    • _deserializeFromOther

      protected Object _deserializeFromOther(JsonParser p, DeserializationContext ctxt, JsonToken t) throws JacksonException
      Throws:
      JacksonException

    • _deserializeEmbedded

      protected T _deserializeEmbedded(Object ob, DeserializationContext ctxt) throws JacksonException
      Overridable method to allow coercion from embedded value that is neither null nor directly assignable to target type. Used, for example, by UUIDDeserializer to coerce from byte[].
      Throws:
      JacksonException

    • _deserializeFromEmptyString

      protected Object _deserializeFromEmptyString(DeserializationContext ctxt) throws JacksonException
      Throws:
      JacksonException

    • _deserializeFromEmptyStringDefault

      protected Object _deserializeFromEmptyStringDefault(DeserializationContext ctxt) throws JacksonException
      Throws:
      JacksonException