org.codehaus.jackson.map.HandlerInstantiator Maven / Gradle / Ivy
package org.codehaus.jackson.map;
import org.codehaus.jackson.map.introspect.Annotated;
import org.codehaus.jackson.map.jsontype.TypeIdResolver;
import org.codehaus.jackson.map.jsontype.TypeResolverBuilder;
/**
* Helper class used for handling details of creating handler instances (things
* like {@link JsonSerializer}s, {@link 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.
*
* @since 1.8
*/
public abstract class HandlerInstantiator
{
/*
/**********************************************************
/* Public API
/**********************************************************
*/
/**
* Method called to get an instance of deserializer of specified type.
*
* @param config Deserialization configuration in effect
* @param annotated Element (Class, Method, Field, constructor parameter) that
* had annotation defining class of deserializer to construct (to allow
* implementation use information from other annotations)
* @param deserClass Class of deserializer instance to return
*
* @return Deserializer instance to use
*/
public abstract JsonDeserializer deserializerInstance(DeserializationConfig config,
Annotated annotated, Class> deserClass);
/**
* Method called to get an instance of key deserializer of specified type.
*
* @param config Deserialization configuration in effect
* @param 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)
* @param keyDeserClass Class of key deserializer instance to return
*
* @return Key deserializer instance to use
*/
public abstract KeyDeserializer keyDeserializerInstance(DeserializationConfig config,
Annotated annotated, Class keyDeserClass);
/**
* Method called to get an instance of serializer of specified type.
*
* @param config Serialization configuration in effect
* @param annotated Element (Class, Method, Field) that
* had annotation defining class of serializer to construct (to allow
* implementation use information from other annotations)
* @param serClass Class of serializer instance to return
*
* @return Serializer instance to use
*/
public abstract JsonSerializer serializerInstance(SerializationConfig config,
Annotated annotated, Class> serClass);
/**
* Method called to get an instance of TypeResolverBuilder of specified type.
*
* @param config Mapper configuration in effect (either SerializationConfig or
* DeserializationConfig, depending on when instance is being constructed)
* @param annotated annotated Element (Class, Method, Field) that
* had annotation defining class of builder to construct (to allow
* implementation use information from other annotations)
* @param builderClass Class of builder instance to return
*
* @return TypeResolverBuilder instance to use
*/
public abstract TypeResolverBuilder typeResolverBuilderInstance(MapperConfig config,
Annotated annotated, Class> builderClass);
/**
* Method called to get an instance of TypeIdResolver of specified type.
*
* @param config Mapper configuration in effect (either SerializationConfig or
* DeserializationConfig, depending on when instance is being constructed)
* @param annotated annotated Element (Class, Method, Field) that
* had annotation defining class of resolver to construct (to allow
* implementation use information from other annotations)
* @param resolverClass Class of resolver instance to return
*
* @return TypeResolverBuilder instance to use
*/
public abstract TypeIdResolver typeIdResolverInstance(MapperConfig config,
Annotated annotated, Class resolverClass);
/**
* Default implementation which simply uses reflection to locate
* zero-argument constructor of given type, and create instance
* using that (possibly forcing access if constructor is not
* public; this can be prevented via configuration)
*/
/*
public static class DefaultImpl
{
@Override
public TypeResolverBuilder typeResolverBuilderInstance(MapperConfig config,
Annotated annotated, Class> builderClass)
{
return ClassUtil.createInstance(builderClass, config.canOverrideAccessModifiers());
}
@Override
public TypeIdResolver typeIdResolverInstance(MapperConfig config,
Annotated annotated, Class resolverClass)
{
return ClassUtil.createInstance(resolverClass, config.canOverrideAccessModifiers());
}
}
*/
}