Package com.fasterxml.jackson.databind.deser.std

Class FactoryBasedEnumDeserializer

java.lang.Object
com.fasterxml.jackson.databind.JsonDeserializer<Object>
com.fasterxml.jackson.databind.deser.std.StdDeserializer<Object>
com.fasterxml.jackson.databind.deser.std.FactoryBasedEnumDeserializer
All Implemented Interfaces:
ContextualDeserializer, NullValueProvider, ValueInstantiator.Gettable, Serializable
class FactoryBasedEnumDeserializer extends StdDeserializer<Object> implements ContextualDeserializer
Deserializer that uses a single-String static factory method for locating Enum values by String id.
Since:
2.8 (as stand-alone class; was static inner class of EnumDeserializer

  • Field Details

  • Constructor Details

  • Method Details

    • createContextual

      public JsonDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property) throws JsonMappingException
      Description copied from interface: ContextualDeserializer
      Method called to see if a different (or differently configured) deserializer is needed to deserialize values of specified property. Note that instance that this method is called on is typically shared one and as a result method should NOT modify this instance but rather construct and return a new instance. This instance should only be returned as-is, in case it is already suitable for use.
      Specified by:
      createContextual in interface ContextualDeserializer
      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.
      Throws:
      JsonMappingException

    • 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 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 JsonDeserializer<Object>

    • logicalType

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

    • 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<Object>

    • getValueInstantiator

      public ValueInstantiator getValueInstantiator()
      Specified by:
      getValueInstantiator in interface ValueInstantiator.Gettable
      Overrides:
      getValueInstantiator in class StdDeserializer<Object>

    • deserialize

      public Object deserialize(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt) throws 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).

      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 JsonDeserializer.getNullValue(DeserializationContext) method is called to produce a null value. To influence null handling, custom deserializers should override JsonDeserializer.getNullValue(DeserializationContext) and usually also JsonDeserializer.getNullAccessPattern().

      Specified by:
      deserialize in class JsonDeserializer<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:
      IOException

    • deserializeWithType

      public Object deserializeWithType(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt, TypeDeserializer typeDeserializer) throws IOException
      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>
      Parameters:
      typeDeserializer - Deserializer to use for handling type information
      Throws:
      IOException

    • deserializeEnumUsingPropertyBased

      protected Object deserializeEnumUsingPropertyBased(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt, PropertyBasedCreator creator) throws IOException
      Throws:
      IOException

    • _deserializeWithErrorWrapping

      protected final Object _deserializeWithErrorWrapping(com.fasterxml.jackson.core.JsonParser p, DeserializationContext ctxt, SettableBeanProperty prop) throws IOException
      Throws:
      IOException

    • wrapAndThrow

      protected Object wrapAndThrow(Throwable t, Object bean, String fieldName, DeserializationContext ctxt) throws IOException
      Throws:
      IOException

    • throwOrReturnThrowable

      private Throwable throwOrReturnThrowable(Throwable t, DeserializationContext ctxt) throws IOException
      Throws:
      IOException