com.fasterxml.jackson.databind.module

Class SimpleAbstractTypeResolver

java.lang.Object

com.fasterxml.jackson.databind.AbstractTypeResolver

com.fasterxml.jackson.databind.module.SimpleAbstractTypeResolver

All Implemented Interfaces:

Serializable

public class SimpleAbstractTypeResolver
extends AbstractTypeResolver
implements Serializable

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)

See Also:

Serialized Form

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 Lists).

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