Package com.fasterxml.jackson.databind.cfg

Class HandlerInstantiator

  • public abstract class HandlerInstantiator
extends java.lang.Object
    Helper class used for handling details of creating handler instances (things like JsonSerializers, JsonDeserializers, various type handlers) of specific types. Actual handler type has been resolved at this point, so instantiator is strictly responsible for providing a configured instance by constructing and configuring a new instance, or possibly by recycling a shared instance. One use case is that of allowing dependency injection, which would otherwise be difficult to do.

    Custom instances are allowed to return null to indicate that caller should use the default instantiation handling (which just means calling no-argument constructor via reflection).

    Care has to be taken to ensure that if instance returned is shared, it will be thread-safe; caller will not synchronize access to returned instances.

    • Constructor Detail

      • HandlerInstantiator

        public HandlerInstantiator()

    • Method Detail

      • deserializerInstance

        public abstract JsonDeserializer<?> deserializerInstance​(DeserializationConfig config,
                                                         Annotated annotated,
                                                         java.lang.Class<?> deserClass)
        Method called to get an instance of deserializer of specified type.
        Parameters:
        config - Deserialization configuration in effect
        annotated - Element (Class, Method, Field, constructor parameter) that had annotation defining class of deserializer to construct (to allow implementation use information from other annotations)
        deserClass - Class of deserializer instance to return
        Returns:
        Deserializer instance to use

      • keyDeserializerInstance

        public abstract KeyDeserializer keyDeserializerInstance​(DeserializationConfig config,
                                                        Annotated annotated,
                                                        java.lang.Class<?> keyDeserClass)
        Method called to get an instance of key deserializer of specified type.
        Parameters:
        config - Deserialization configuration in effect
        annotated - Element (Class, Method, Field, constructor parameter) that had annotation defining class of key deserializer to construct (to allow implementation use information from other annotations)
        keyDeserClass - Class of key deserializer instance to return
        Returns:
        Key deserializer instance to use

      • serializerInstance

        public abstract JsonSerializer<?> serializerInstance​(SerializationConfig config,
                                                     Annotated annotated,
                                                     java.lang.Class<?> serClass)
        Method called to get an instance of serializer of specified type.
        Parameters:
        config - Serialization configuration in effect
        annotated - Element (Class, Method, Field) that had annotation defining class of serializer to construct (to allow implementation use information from other annotations)
        serClass - Class of serializer instance to return
        Returns:
        Serializer instance to use

      • typeResolverBuilderInstance

        public abstract TypeResolverBuilder<?> typeResolverBuilderInstance​(MapperConfig<?> config,
                                                                   Annotated annotated,
                                                                   java.lang.Class<?> builderClass)
        Method called to get an instance of TypeResolverBuilder of specified type.
        Parameters:
        config - Mapper configuration in effect (either SerializationConfig or DeserializationConfig, depending on when instance is being constructed)
        annotated - annotated Element (Class, Method, Field) that had annotation defining class of builder to construct (to allow implementation use information from other annotations)
        builderClass - Class of builder instance to return
        Returns:
        TypeResolverBuilder instance to use

      • typeIdResolverInstance

        public abstract TypeIdResolver typeIdResolverInstance​(MapperConfig<?> config,
                                                      Annotated annotated,
                                                      java.lang.Class<?> resolverClass)
        Method called to get an instance of TypeIdResolver of specified type.
        Parameters:
        config - Mapper configuration in effect (either SerializationConfig or DeserializationConfig, depending on when instance is being constructed)
        annotated - annotated Element (Class, Method, Field) that had annotation defining class of resolver to construct (to allow implementation use information from other annotations)
        resolverClass - Class of resolver instance to return
        Returns:
        TypeResolverBuilder instance to use

      • valueInstantiatorInstance

        public ValueInstantiator valueInstantiatorInstance​(MapperConfig<?> config,
                                                   Annotated annotated,
                                                   java.lang.Class<?> resolverClass)
        Method called to construct an instance of ValueInstantiator of specified type.

      • objectIdGeneratorInstance

        public ObjectIdGenerator<?> objectIdGeneratorInstance​(MapperConfig<?> config,
                                                      Annotated annotated,
                                                      java.lang.Class<?> implClass)
        Method called to construct a ObjectIdHandler instance of specified type.
        Since:
        2.0

      • namingStrategyInstance

        public PropertyNamingStrategy namingStrategyInstance​(MapperConfig<?> config,
                                                     Annotated annotated,
                                                     java.lang.Class<?> implClass)
        Method called to construct a NamingStrategy instance used for specified class.
        Since:
        2.1

      • converterInstance

        public Converter<?,​?> converterInstance​(MapperConfig<?> config,
                                              Annotated annotated,
                                              java.lang.Class<?> implClass)
        Method called to construct a Converter instance used for specified class.
        Since:
        2.2

      • includeFilterInstance

        public java.lang.Object includeFilterInstance​(SerializationConfig config,
                                              BeanPropertyDefinition forProperty,
                                              java.lang.Class<?> filterClass)
        Method called to construct a Filter (any Object with implementation of equals(Object) that determines if given value is to be excluded (true) or included (false)) to be used based on JsonInclude annotation (or equivalent).

        Default implementation returns `null` to indicate that default instantiation (use zero-arg constructor of the filterClass) should be used.

        Since:
        2.9