Package com.fasterxml.jackson.databind.deser

Interface Deserializers

  • All Known Implementing Classes:
    CoreXMLDeserializers, Deserializers.Base, SimpleDeserializers
    public interface Deserializers
    Interface that defines API for simple extensions that can provide additional deserializers for various types. Access is by a single callback method; instance is to either return a configured JsonDeserializer for specified type, or null to indicate that it does not support handling of the type. In latter case, further calls can be made for other providers; in former case returned deserializer is used for handling of instances of specified type.

    It is strongly recommended that implementations always extend Deserializers.Base and NOT just implement Deserializers.

    • Method Detail

      • findEnumDeserializer

        JsonDeserializer<?> findEnumDeserializer​(Class<?> type,
                                         DeserializationConfig config,
                                         BeanDescription beanDesc)
                                  throws JsonMappingException
        Method called to locate deserializer for specified Enum type.
        Parameters:
        type - Type of Enum instances to deserialize
        config - Configuration in effect
        beanDesc - Definition of the enumeration type that contains class annotations and other information typically needed for building deserializers
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException

      • findBeanDeserializer

        JsonDeserializer<?> findBeanDeserializer​(JavaType type,
                                         DeserializationConfig config,
                                         BeanDescription beanDesc)
                                  throws JsonMappingException
        Method called to locate deserializer for specified value type which does not belong to any other category (not an Enum, Collection, Map, Array, reference value or tree node)
        Parameters:
        type - Bean type to deserialize
        config - Configuration in effect
        beanDesc - Definition of the enumeration type that contains class annotations and other information typically needed for building deserializers
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException

      • findReferenceDeserializer

        JsonDeserializer<?> findReferenceDeserializer​(ReferenceType refType,
                                              DeserializationConfig config,
                                              BeanDescription beanDesc,
                                              TypeDeserializer contentTypeDeserializer,
                                              JsonDeserializer<?> contentDeserializer)
                                       throws JsonMappingException
        Method called to locate deserializer for value that is of referential type,
        Parameters:
        refType - Specific referential type to deserialize
        config - Configuration in effect
        beanDesc - Definition of the reference type that contains class annotations and other information typically needed for building deserializers
        contentTypeDeserializer - Possible type deserializer for referenced value
        contentDeserializer - Value deserializer to use for referenced value, if indicated by property annotation
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException
        Since:
        2.7

      • findArrayDeserializer

        JsonDeserializer<?> findArrayDeserializer​(ArrayType type,
                                          DeserializationConfig config,
                                          BeanDescription beanDesc,
                                          TypeDeserializer elementTypeDeserializer,
                                          JsonDeserializer<?> elementDeserializer)
                                   throws JsonMappingException
        Method called to locate serializer for specified array type.

        Deserializer for element type may be passed, if configured explicitly at higher level (by annotations, typically), but usually are not. Type deserializer for element is passed if one is needed based on contextual information (annotations on declared element class; or on field or method type is associated with).

        Parameters:
        type - Type of array instances to deserialize
        config - Configuration in effect
        beanDesc - Definition of the enumeration type that contains class annotations and other information typically needed for building deserializers
        elementTypeDeserializer - If element type needs polymorphic type handling, this is the type information deserializer to use; should usually be used as is when constructing array deserializer.
        elementDeserializer - Deserializer to use for elements, if explicitly defined (by using annotations, for exmple). May be null, in which case it should be resolved here (or using ResolvableDeserializer callback)
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException

      • findCollectionDeserializer

        JsonDeserializer<?> findCollectionDeserializer​(CollectionType type,
                                               DeserializationConfig config,
                                               BeanDescription beanDesc,
                                               TypeDeserializer elementTypeDeserializer,
                                               JsonDeserializer<?> elementDeserializer)
                                        throws JsonMappingException
        Method called to locate serializer for specified Collection (List, Set etc) type.

        Deserializer for element type may be passed, if configured explicitly at higher level (by annotations, typically), but usually are not. Type deserializer for element is passed if one is needed based on contextual information (annotations on declared element class; or on field or method type is associated with).

        Parameters:
        type - Type of collection instances to deserialize
        config - Configuration in effect
        beanDesc - Definition of the enumeration type that contains class annotations and other information typically needed for building deserializers
        elementTypeDeserializer - If element type needs polymorphic type handling, this is the type information deserializer to use; should usually be used as is when constructing array deserializer.
        elementDeserializer - Deserializer to use for elements, if explicitly defined (by using annotations, for exmple). May be null, in which case it should be resolved here (or using ResolvableDeserializer callback)
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException

      • findCollectionLikeDeserializer

        JsonDeserializer<?> findCollectionLikeDeserializer​(CollectionLikeType type,
                                                   DeserializationConfig config,
                                                   BeanDescription beanDesc,
                                                   TypeDeserializer elementTypeDeserializer,
                                                   JsonDeserializer<?> elementDeserializer)
                                            throws JsonMappingException
        Method called to locate serializer for specified "Collection-like" type (one that acts like Collection but does not implement it).

        Deserializer for element type may be passed, if configured explicitly at higher level (by annotations, typically), but usually are not. Type deserializer for element is passed if one is needed based on contextual information (annotations on declared element class; or on field or method type is associated with).

        Parameters:
        type - Type of instances to deserialize
        config - Configuration in effect
        beanDesc - Definition of the enumeration type that contains class annotations and other information typically needed for building deserializers
        elementTypeDeserializer - If element type needs polymorphic type handling, this is the type information deserializer to use; should usually be used as is when constructing array deserializer.
        elementDeserializer - Deserializer to use for elements, if explicitly defined (by using annotations, for exmple). May be null, in which case it should be resolved here (or using ResolvableDeserializer callback)
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException

      • findMapDeserializer

        JsonDeserializer<?> findMapDeserializer​(MapType type,
                                        DeserializationConfig config,
                                        BeanDescription beanDesc,
                                        KeyDeserializer keyDeserializer,
                                        TypeDeserializer elementTypeDeserializer,
                                        JsonDeserializer<?> elementDeserializer)
                                 throws JsonMappingException
        Method called to locate deserializer for specified Map type.

        Deserializer for element type may be passed, if configured explicitly at higher level (by annotations, typically), but usually are not. Type deserializer for element is passed if one is needed based on contextual information (annotations on declared element class; or on field or method type is associated with).

        Similarly, a KeyDeserializer may be passed, but this is only done if there is a specific configuration override (annotations) to indicate instance to use. Otherwise null is passed, and key deserializer needs to be obtained later during resolution (using ResolvableDeserializer.resolve(com.fasterxml.jackson.databind.DeserializationContext)).

        Parameters:
        type - Type of Map instances to deserialize
        config - Configuration in effect
        beanDesc - Definition of the enumeration type that contains class annotations and other information typically needed for building deserializers
        keyDeserializer - Key deserializer use, if it is defined via annotations or other configuration; null if default key deserializer for key type can be used.
        elementTypeDeserializer - If element type needs polymorphic type handling, this is the type information deserializer to use; should usually be used as is when constructing array deserializer.
        elementDeserializer - Deserializer to use for elements, if explicitly defined (by using annotations, for exmple). May be null, in which case it should be resolved here (or using ResolvableDeserializer callback)
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException

      • findMapLikeDeserializer

        JsonDeserializer<?> findMapLikeDeserializer​(MapLikeType type,
                                            DeserializationConfig config,
                                            BeanDescription beanDesc,
                                            KeyDeserializer keyDeserializer,
                                            TypeDeserializer elementTypeDeserializer,
                                            JsonDeserializer<?> elementDeserializer)
                                     throws JsonMappingException
        Method called to locate serializer for specified "Map-like" type (one that acts like Map but does not implement it).

        Deserializer for element type may be passed, if configured explicitly at higher level (by annotations, typically), but usually are not. Type deserializer for element is passed if one is needed based on contextual information (annotations on declared element class; or on field or method type is associated with).

        Similarly, a KeyDeserializer may be passed, but this is only done if there is a specific configuration override (annotations) to indicate instance to use. Otherwise null is passed, and key deserializer needs to be obtained later during resolution (using ResolvableDeserializer.resolve(com.fasterxml.jackson.databind.DeserializationContext)).

        Parameters:
        type - Type of Map instances to deserialize
        config - Configuration in effect
        beanDesc - Definition of the enumeration type that contains class annotations and other information typically needed for building deserializers
        keyDeserializer - Key deserializer use, if it is defined via annotations or other configuration; null if default key deserializer for key type can be used.
        elementTypeDeserializer - If element type needs polymorphic type handling, this is the type information deserializer to use; should usually be used as is when constructing array deserializer.
        elementDeserializer - Deserializer to use for elements, if explicitly defined (by using annotations, for exmple). May be null, in which case it should be resolved here (or using ResolvableDeserializer callback)
        Returns:
        Deserializer to use for the type; or null if this provider does not know how to construct it
        Throws:
        JsonMappingException

      • hasDeserializerFor

        default boolean hasDeserializerFor​(DeserializationConfig config,
                                   Class<?> valueType)
        Method that may be called to check whether this deserializer provider would provide deserializer for values of given type, without attempting to construct (and possibly fail in some cases) actual deserializer. Mostly needed to support validation of polymorphic type ids.

        Note: implementations should take care NOT to claim supporting types that they do not recognize as this could to incorrect assumption of safe support by caller.

        Method added in Jackson 2.13 now that Java 8 default implementations are available for use with interface definitions.

        Since:
        2.13