BeanDeserializerModifier.java
package com.fasterxml.jackson.databind.deser;
import java.util.List;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.introspect.BeanPropertyDefinition;
import com.fasterxml.jackson.databind.type.ArrayType;
import com.fasterxml.jackson.databind.type.CollectionLikeType;
import com.fasterxml.jackson.databind.type.CollectionType;
import com.fasterxml.jackson.databind.type.MapLikeType;
import com.fasterxml.jackson.databind.type.MapType;
import com.fasterxml.jackson.databind.type.ReferenceType;
/**
* Abstract class that defines API for objects that can be registered
* to participate in constructing {@link JsonDeserializer} instances
* (via {@link DeserializerFactory}).
* This is typically done by modules that want alter some aspects of deserialization
* process; and is preferable to sub-classing of {@link BeanDeserializerFactory}.
*<p>
* Note that Jackson 2.2 adds more methods for customization; with earlier versions
* only {@link BeanDeserializer} instances could be modified, but with 2.2 all types
* of deserializers can be changed.
*<p>
* Sequence in which callback methods are called for {@link BeanDeserializer} is:
* <ol>
* <li>{@link #updateProperties} is called once all property definitions are
* collected, and initial filtering (by ignorable type and explicit ignoral-by-bean)
* has been performed.
* </li>
* <li>{@link #updateBuilder} is called once all initial pieces for building deserializer
* have been collected
* </li>
* <li>{@link #modifyDeserializer} is called after deserializer has been built
* by {@link BeanDeserializerBuilder}
* but before it is returned to be used
* </li>
* </ol>
*<p>
* For other types of deserializers, methods called depend on type of values for
* which deserializer is being constructed; and only a single method is called
* since the process does not involve builders (unlike that of {@link BeanDeserializer}.
*<p>
* Default method implementations are "no-op"s, meaning that methods are implemented
* but have no effect; this is mostly so that new methods can be added in later
* versions.
*/
public abstract class BeanDeserializerModifier
{
/**
* Method called by {@link BeanDeserializerFactory} when it has collected
* initial list of {@link BeanPropertyDefinition}s, and done basic by-name
* and by-type filtering, but before constructing builder or actual
* property handlers; or arranging order.
*
* The most common changes to make at this point are to completely remove
* specified properties, or rename then: other modifications are easier
* to make at later points.
*/
public List<BeanPropertyDefinition> updateProperties(DeserializationConfig config,
BeanDescription beanDesc, List<BeanPropertyDefinition> propDefs) {
return propDefs;
}
/**
* Method called by {@link BeanDeserializerFactory} when it has collected
* basic information such as tentative list of properties to deserialize.
*
* Implementations may choose to modify state of builder (to affect deserializer being
* built), or even completely replace it (if they want to build different kind of
* deserializer). Typically changes mostly concern set of properties to deserialize.
*/
public BeanDeserializerBuilder updateBuilder(DeserializationConfig config,
BeanDescription beanDesc, BeanDeserializerBuilder builder) {
return builder;
}
/**
* Method called by {@link BeanDeserializerFactory} after constructing default
* bean deserializer instance with properties collected and ordered earlier.
* Implementations can modify or replace given deserializer and return deserializer
* to use. Note that although initial deserializer being passed is usually of type
* {@link BeanDeserializer}, modifiers may return deserializers of other types;
* and this is why implementations must check for type before casting.
*<p>
* Since 2.10 this is also called for custom deserializers for types not deemed to
* be of any more specific (reference, enum, array, collection(-like), map(-like),
* node type)
*/
public JsonDeserializer<?> modifyDeserializer(DeserializationConfig config,
BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/*
/**********************************************************
/* Callback methods for other types (since 2.2)
/**********************************************************
*/
/**
* Method called by {@link BeanDeserializerFactory} after constructing default
* enum type deserializer instance.
*
* @since 2.2
*/
public JsonDeserializer<?> modifyEnumDeserializer(DeserializationConfig config,
JavaType type, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/**
* Method called by {@link BeanDeserializerFactory} after constructing default
* {@link ReferenceType} deserializer instance.
*
* @since 2.7
*/
public JsonDeserializer<?> modifyReferenceDeserializer(DeserializationConfig config,
ReferenceType type, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/**
* Method called by {@link DeserializerFactory} after it has constructed the
* standard deserializer for given
* {@link ArrayType}
* to make it possible to either replace or augment this deserializer with
* additional functionality.
*
* @param config Configuration in use
* @param valueType Type of the value deserializer is used for.
* @param beanDesc Description f
* @param deserializer Default deserializer that would be used.
*
* @return Deserializer to use; either <code>deserializer</code> that was passed
* in, or an instance method constructed.
*
* @since 2.2
*/
public JsonDeserializer<?> modifyArrayDeserializer(DeserializationConfig config,
ArrayType valueType, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/**
* Method called by {@link BeanDeserializerFactory} after constructing default
* {@link CollectionType} deserializer instance.
*
* @since 2.2
*/
public JsonDeserializer<?> modifyCollectionDeserializer(DeserializationConfig config,
CollectionType type, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/**
* Method called by {@link BeanDeserializerFactory} after constructing default
* {@link CollectionLikeType} deserializer instance.
*
* @since 2.2
*/
public JsonDeserializer<?> modifyCollectionLikeDeserializer(DeserializationConfig config,
CollectionLikeType type, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/**
* Method called by {@link BeanDeserializerFactory} after constructing default
* {@link MapType} deserializer instance.
*
* @since 2.2
*/
public JsonDeserializer<?> modifyMapDeserializer(DeserializationConfig config,
MapType type, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/**
* Method called by {@link BeanDeserializerFactory} after constructing default
* {@link MapLikeType} deserializer instance.
*
* @since 2.2
*/
public JsonDeserializer<?> modifyMapLikeDeserializer(DeserializationConfig config,
MapLikeType type, BeanDescription beanDesc, JsonDeserializer<?> deserializer) {
return deserializer;
}
/**
* Method called by {@link DeserializerFactory} after it has constructed the
* standard key deserializer for given key type.
* This make it possible to replace the default key deserializer, or augment
* it somehow (including optional use of default deserializer with occasional
* override).
*
* @since 2.2
*/
public KeyDeserializer modifyKeyDeserializer(DeserializationConfig config,
JavaType type, KeyDeserializer deserializer) {
return deserializer;
}
}