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 JsonDeserializer instances (via DeserializerFactory). This is typically done by modules that want alter some aspects of deserialization process; and is preferable to sub-classing of BeanDeserializerFactory. 
 Note that Jackson 2.2 adds more methods for customization; with earlier versions only BeanDeserializer instances could be modified, but with 2.2 all types of deserializers can be changed. 
 Sequence in which callback methods are called for BeanDeserializer is: 

 
updateProperties is called once all property definitions are collected, and initial filtering (by ignorable type and explicit ignoral-by-bean) has been performed. 
 
updateBuilder is called once all initial pieces for building deserializer have been collected 
 
modifyDeserializer is called after deserializer has been built by BeanDeserializerBuilder but before it is returned to be used 

 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 BeanDeserializer. 

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.
/**
 * 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 BeanDeserializerFactory when it has collected initial list of BeanPropertyDefinitions, 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. /**
     * 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 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. /**
     * 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 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 BeanDeserializer, modifiers may return deserializers of other types; and this is why implementations must check for type before casting. 

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)
/**
     * 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 BeanDeserializerFactory after constructing default enum type deserializer instance. 
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 BeanDeserializerFactory after constructing default ReferenceType deserializer instance. 
Since:
2.7/**
     * 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 DeserializerFactory after it has constructed the standard deserializer for given ArrayType to make it possible to either replace or augment this deserializer with additional functionality. 
Params:
config – Configuration in use
valueType – Type of the value deserializer is used for.
beanDesc – Description f
deserializer – Default deserializer that would be used.
Returns:
Deserializer to use; either deserializer that was passed
  in, or an instance method constructed.
Since:
2.2/**
     * 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 BeanDeserializerFactory after constructing default CollectionType deserializer instance. 
Since:
2.2/**
     * 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 BeanDeserializerFactory after constructing default CollectionLikeType deserializer instance. 
Since:
2.2/**
     * 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 BeanDeserializerFactory after constructing default MapType deserializer instance. 
Since:
2.2/**
     * 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 BeanDeserializerFactory after constructing default MapLikeType deserializer instance. 
Since:
2.2/**
     * 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 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/**
     * 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;
    }
}