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

Class EnumDeserializer

java.lang.Object
tools.jackson.databind.ValueDeserializer<T>
tools.jackson.databind.deser.std.StdDeserializer<T>
tools.jackson.databind.deser.std.StdScalarDeserializer<Object>
tools.jackson.databind.deser.jdk.EnumDeserializer
All Implemented Interfaces:
NullValueProvider, ValueInstantiator.Gettable
public class EnumDeserializer extends StdScalarDeserializer<Object>
Deserializer class that can deserialize instances of specified Enum class from Strings and Integers.

  • Field Details

    • _enumsByIndex

      protected Object[] _enumsByIndex

    • _lookupByName

      protected final CompactStringObjectMap _lookupByName

    • _lookupByToString

      protected final CompactStringObjectMap _lookupByToString
      Alternatively, we may need a different lookup object if "use toString" is defined.

    • _caseInsensitive

      protected final Boolean _caseInsensitive

    • _isFromIntValue

      protected final boolean _isFromIntValue
      Marker flag for cases where we expect actual integral value for Enum, based on @JsonValue (and equivalent) annotated accessor.

    • _hasAsValueAnnotation

      protected final boolean _hasAsValueAnnotation
      Marker flag that indicates whether the Enum class has @JsonValue annotated accessor (or equivalent), used to populate _lookupByName.
      Since:
      2.20

    • _lookupByEnumNaming

      protected final CompactStringObjectMap _lookupByEnumNaming
      Look up map with key as Enum.name() converted by EnumNamingStrategy.convertEnumToExternalName(MapperConfig, AnnotatedClass, String) and value as Enums.

  • Constructor Details

    • EnumDeserializer

      public EnumDeserializer(EnumResolver byNameResolver, boolean caseInsensitive, EnumResolver byEnumNamingResolver, EnumResolver toStringResolver)

    • EnumDeserializer

      protected EnumDeserializer(EnumDeserializer base, boolean caseInsensitive, Boolean useDefaultValueForUnknownEnum, Boolean useNullForUnknownEnum)

  • Method Details

    • deserializerForCreator

      public static ValueDeserializer<?> deserializerForCreator(DeserializationConfig config, Class<?> enumClass, AnnotatedMethod factory, ValueInstantiator valueInstantiator, SettableBeanProperty[] creatorProps, EnumResolver byNameResolver)
      Factory method used when Enum instances are to be deserialized using a creator (static factory method)
      Returns:
      Deserializer based on given factory method

    • deserializerForNoArgsCreator

      public static ValueDeserializer<?> deserializerForNoArgsCreator(DeserializationConfig config, Class<?> enumClass, AnnotatedMethod factory)
      Factory method used when Enum instances are to be deserialized using a zero-/no-args factory method
      Returns:
      Deserializer based on given no-args factory method

    • withResolved

      public EnumDeserializer withResolved(Boolean caseInsensitive, Boolean useDefaultValueForUnknownEnum, Boolean useNullForUnknownEnum)

    • createContextual

      public ValueDeserializer<?> createContextual(DeserializationContext ctxt, BeanProperty property)
      Description copied from class: ValueDeserializer
      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.
      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()
      Because of costs associated with constructing Enum resolvers, let's cache instances by default.
      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 StdScalarDeserializer<Object>
      Returns:
      Logical type of values this deserializer produces, if known; null if not

    • getEmptyValue

      public Object getEmptyValue(DeserializationContext ctxt)
      Description copied from class: ValueDeserializer
      Method called to determine value to be used for "empty" values (most commonly when deserializing from empty JSON Strings). Usually this is same as ValueDeserializer.getNullValue(tools.jackson.databind.DeserializationContext) (which in turn is usually simply Java null), but it can be overridden for specific types. Or, if type should never be converted from empty String, method can also throw an exception.

      This method may be called once, or multiple times, depending on what ValueDeserializer.getEmptyAccessPattern() returns.

      Default implementation simply calls ValueDeserializer.getNullValue(tools.jackson.databind.DeserializationContext) and returns value.

      Overrides:
      getEmptyValue 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

    • _fromString

      protected Object _fromString(JsonParser p, DeserializationContext ctxt, String text) throws JacksonException
      Throws:
      JacksonException

    • _fromInteger

      protected Object _fromInteger(JsonParser p, DeserializationContext ctxt, int index) throws JacksonException
      Throws:
      JacksonException

    • _deserializeOther

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

    • _enumClass

      protected Class<?> _enumClass()

    • useNullForUnknownEnum

      protected boolean useNullForUnknownEnum(DeserializationContext ctxt)

    • useDefaultValueForUnknownEnum

      protected boolean useDefaultValueForUnknownEnum(DeserializationContext ctxt)