SimpleAbstractTypeResolver (Jackson JSON Processor)
Date: 2013-07-14

org.codehaus.jackson.map.module

## Class SimpleAbstractTypeResolver

- java.lang.Object
- - org.codehaus.jackson.map.AbstractTypeResolver
  - - org.codehaus.jackson.map.module.SimpleAbstractTypeResolver

-     public class SimpleAbstractTypeResolver
      extends AbstractTypeResolver

  Simple `AbstractTypeResolver` implementation, which is based on static mapping from abstract super types into sub types (concrete or abstract), but retaining generic parameterization. Can be used for things like specifying which implementation of `Collection` to use:

        SimpleAbstractTypeResolver resolver = new SimpleAbstractTypeResolver();
        // To make all properties declared as Collection, List, to LinkedList
        resolver.addMapping(Collection.class, LinkedList.class);
        resolver.addMapping(List.class, LinkedList.class);

  Can also be used as an alternative to per-class annotations when defining concrete implementations; however, only works with abstract types (since this is only called for abstract types)
  Since:
    1.8

- - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `protected HashMap<ClassKey,Class<?>>` | `_mappings` Mappings from super types to subtypes

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `SimpleAbstractTypeResolver()`

  - ### Method Summary

    Methods
    Modifier and Type | Method and Description
    --- | ---
    `<T> SimpleAbstractTypeResolver` | `addMapping(Class<T> superType, Class<? extends T> subType)` Method for adding a mapping from super type to specific subtype.
    `JavaType` | `findTypeMapping(DeserializationConfig config, JavaType type)` Try to locate a subtype for given abstract type, to either resolve to a concrete type, or at least to a more-specific (and hopefully supported) abstract type, one which may have registered deserializers.
    `JavaType` | `resolveAbstractType(DeserializationConfig config, JavaType type)` Method called to try to resolve an abstract type into concrete type (usually for purposes of deserializing), when no concrete implementation was found.

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

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

- - ### Field Detail

    - #### _mappings

          protected final HashMap<ClassKey,Class<?>> _mappings

      Mappings from super types to subtypes

  - ### Constructor Detail

    - #### SimpleAbstractTypeResolver

          public SimpleAbstractTypeResolver()

  - ### Method Detail

    - #### addMapping

          public <T> SimpleAbstractTypeResolver addMapping(Class<T> superType,
                                                  Class<? extends T> subType)

      Method for adding a mapping from super type to specific subtype. Arguments will be checked by method, to ensure that `superType` is abstract (since resolver is never called for concrete classes); as well as to ensure that there is supertype/subtype relationship (to ensure there won't be cycles during resolution).
      Parameters:
        `superType` - Abstract type to resolve
        `subType` - Sub-class of superType, to map superTo to
      Returns:
        This resolver, to allow chaining of initializations

    - #### findTypeMapping

          public JavaType findTypeMapping(DeserializationConfig config,
                                 JavaType type)

      Description copied from class: `AbstractTypeResolver`
      Try to locate a subtype for given abstract type, to either resolve to a concrete type, or at least to a more-specific (and hopefully supported) abstract type, one which may have registered deserializers. Method is called before trying to locate registered deserializers (as well as standard abstract type defaulting that core Jackson does), so it is typically implemented to add custom mappings of common abstract types (like specify which concrete implementation to use for binding `List`s).

      Note that this method does not necessarily have to do full resolution of bindings; that is, it is legal to return type that could be further resolved: caller is expected to keep calling this method on registered resolvers, until a concrete type is located.

      Overrides:
        `findTypeMapping` in class `AbstractTypeResolver`
      Parameters:
        `config` - Configuration in use; should always be of type `DeserializationConfig`

    - #### resolveAbstractType

          public JavaType resolveAbstractType(DeserializationConfig config,
                                     JavaType type)

      Description copied from class: `AbstractTypeResolver`
      Method called to try to resolve an abstract type into concrete type (usually for purposes of deserializing), when no concrete implementation was found. It will be called after checking all other possibilities, including defaulting.
      Overrides:
        `resolveAbstractType` in class `AbstractTypeResolver`
      Parameters:
        `config` - Configuration in use; should always be of type `DeserializationConfig`
        `type` - Type for which materialization maybe needed
      Returns:
        Resolved concrete type (which should retain generic type parameters of input type, if any), if resolution succeeds; null if resolver does not know how to resolve type