com.fasterxml.jackson.databind.cfg

## Class HandlerInstantiator

- java.lang.Object
- - com.fasterxml.jackson.databind.cfg.HandlerInstantiator

-     public abstract class HandlerInstantiator
      extends Object

  Helper class used for handling details of creating handler instances (things like `JsonSerializer`s, `JsonDeserializer`s, 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 Summary

    Constructors
    Constructor and Description
    `HandlerInstantiator()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `Converter<?,?>` | `converterInstance(MapperConfig<?> config, Annotated annotated, Class<?> implClass)` Method called to construct a Converter instance used for specified class.
    `abstract JsonDeserializer<?>` | `deserializerInstance(DeserializationConfig config, Annotated annotated, Class<?> deserClass)` Method called to get an instance of deserializer of specified type.
    `abstract KeyDeserializer` | `keyDeserializerInstance(DeserializationConfig config, Annotated annotated, Class<?> keyDeserClass)` Method called to get an instance of key deserializer of specified type.
    `PropertyNamingStrategy` | `namingStrategyInstance(MapperConfig<?> config, Annotated annotated, Class<?> implClass)` Method called to construct a NamingStrategy instance used for specified class.
    `ObjectIdGenerator<?>` | `objectIdGeneratorInstance(MapperConfig<?> config, Annotated annotated, Class<?> implClass)` Method called to construct a ObjectIdHandler instance of specified type.
    `abstract JsonSerializer<?>` | `serializerInstance(SerializationConfig config, Annotated annotated, Class<?> serClass)` Method called to get an instance of serializer of specified type.
    `abstract TypeIdResolver` | `typeIdResolverInstance(MapperConfig<?> config, Annotated annotated, Class<?> resolverClass)` Method called to get an instance of TypeIdResolver of specified type.
    `abstract TypeResolverBuilder<?>` | `typeResolverBuilderInstance(MapperConfig<?> config, Annotated annotated, Class<?> builderClass)` Method called to get an instance of TypeResolverBuilder of specified type.
    `ValueInstantiator` | `valueInstantiatorInstance(MapperConfig<?> config, Annotated annotated, Class<?> resolverClass)` Method called to construct an instance of ValueInstantiator of specified type.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### HandlerInstantiator

          public HandlerInstantiator()

  - ### Method Detail

    - #### deserializerInstance

          public abstract JsonDeserializer<?> deserializerInstance(DeserializationConfig config,
                                                 Annotated annotated,
                                                 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,
                                                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,
                                             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,
                                                           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,
                                              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,
                                                    Class<?> resolverClass)

      Method called to construct an instance of ValueInstantiator of specified type.

    - #### objectIdGeneratorInstance

          public ObjectIdGenerator<?> objectIdGeneratorInstance(MapperConfig<?> config,
                                                       Annotated annotated,
                                                       Class<?> implClass)

      Method called to construct a ObjectIdHandler instance of specified type.
      Since:
        2.0

    - #### namingStrategyInstance

          public PropertyNamingStrategy namingStrategyInstance(MapperConfig<?> config,
                                                      Annotated annotated,
                                                      Class<?> implClass)

      Method called to construct a NamingStrategy instance used for specified class.
      Since:
        2.1

    - #### converterInstance

          public Converter<?,?> converterInstance(MapperConfig<?> config,
                                         Annotated annotated,
                                         Class<?> implClass)

      Method called to construct a Converter instance used for specified class.
      Since:
        2.2

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