Jackson is "the Java JSON library" or "the best JSON parser for Java". Or simply as "JSON for Java".

Jackson Databind Source Code files are provided in the source packge (jackson-databind-2.14.0-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Databind Source Code below:

⏎ com/fasterxml/jackson/databind/deser/Deserializers.java

package com.fasterxml.jackson.databind.deser;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.type.*;

/**
 * Interface that defines API for simple extensions that can provide additional deserializers
 * for various types. Access is by a single callback method; instance is to either return
 * a configured {@link JsonDeserializer} for specified type, or null to indicate that it
 * does not support handling of the type. In latter case, further calls can be made
 * for other providers; in former case returned deserializer is used for handling of
 * instances of specified type.
 *<p>
 * It is <b>strongly recommended</b> that implementations always extend {@link Deserializers.Base}
 * and NOT just implement {@link Deserializers}.
 */
public interface Deserializers
{
    // // // Scalar types first:

    /**
     * Method called to locate deserializer for specified {@link java.lang.Enum} type.
     * 
     * @param type Type of {@link java.lang.Enum} instances to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the enumeration type that contains class annotations and
     *    other information typically needed for building deserializers
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findEnumDeserializer(Class<?> type,
            DeserializationConfig config, BeanDescription beanDesc)
        throws JsonMappingException;

    /**
     * Method called to locate deserializer for specified JSON tree node type.
     * 
     * @param nodeType Specific type of JSON tree nodes to deserialize
     *  (subtype of {@link com.fasterxml.jackson.databind.JsonNode})
     * @param config Configuration in effect
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findTreeNodeDeserializer(Class<? extends JsonNode> nodeType,
            DeserializationConfig config, BeanDescription beanDesc)
        throws JsonMappingException;

    /**
     * Method called to locate deserializer for specified value type which does not belong to any other
     * category (not an Enum, Collection, Map, Array, reference value or tree node)
     * 
     * @param type Bean type to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the enumeration type that contains class annotations and
     *    other information typically needed for building deserializers
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findBeanDeserializer(JavaType type,
            DeserializationConfig config, BeanDescription beanDesc)
        throws JsonMappingException;
    
    // // // Then container types
    
    /**
     * Method called to locate deserializer for value that is of referential
     * type,
     * 
     * @param refType Specific referential type to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the reference type that contains class annotations and
     *    other information typically needed for building deserializers
     * @param contentTypeDeserializer Possible type deserializer for referenced value
     * @param contentDeserializer Value deserializer to use for referenced value, if indicated
     *    by property annotation
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     *
     * @since 2.7
     */
    public JsonDeserializer<?> findReferenceDeserializer(ReferenceType refType,
            DeserializationConfig config, BeanDescription beanDesc,
            TypeDeserializer contentTypeDeserializer, JsonDeserializer<?> contentDeserializer)
        throws JsonMappingException;

    /**
     * Method called to locate serializer for specified array type.
     *<p>
     * Deserializer for element type may be passed, if configured explicitly at higher level (by
     * annotations, typically), but usually are not.
     * Type deserializer for element is passed if one is needed based on contextual information
     * (annotations on declared element class; or on field or method type is associated with).
     * 
     * @param type Type of array instances to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the enumeration type that contains class annotations and
     *    other information typically needed for building deserializers
     * @param elementTypeDeserializer If element type needs polymorphic type handling, this is
     *    the type information deserializer to use; should usually be used as is when constructing
     *    array deserializer.
     * @param elementDeserializer Deserializer to use for elements, if explicitly defined (by using
     *    annotations, for exmple). May be null, in which case it should be resolved here (or using
     *    {@link ResolvableDeserializer} callback)
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findArrayDeserializer(ArrayType type,
            DeserializationConfig config, BeanDescription beanDesc,
            TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
        throws JsonMappingException;

    
    /**
     * Method called to locate serializer for specified {@link java.util.Collection} (List, Set etc) type.
     *<p>
     * Deserializer for element type may be passed, if configured explicitly at higher level (by
     * annotations, typically), but usually are not.
     * Type deserializer for element is passed if one is needed based on contextual information
     * (annotations on declared element class; or on field or method type is associated with).
     * 
     * @param type Type of collection instances to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the enumeration type that contains class annotations and
     *    other information typically needed for building deserializers
     * @param elementTypeDeserializer If element type needs polymorphic type handling, this is
     *    the type information deserializer to use; should usually be used as is when constructing
     *    array deserializer.
     * @param elementDeserializer Deserializer to use for elements, if explicitly defined (by using
     *    annotations, for exmple). May be null, in which case it should be resolved here (or using
     *    {@link ResolvableDeserializer} callback)
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findCollectionDeserializer(CollectionType type,
            DeserializationConfig config, BeanDescription beanDesc,
            TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
        throws JsonMappingException;

    /**
     * Method called to locate serializer for specified
     * "Collection-like" type (one that acts
     * like {@link java.util.Collection} but does not implement it).
     *<p>
     * Deserializer for element type may be passed, if configured explicitly at higher level (by
     * annotations, typically), but usually are not.
     * Type deserializer for element is passed if one is needed based on contextual information
     * (annotations on declared element class; or on field or method type is associated with).
     * 
     * @param type Type of instances to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the enumeration type that contains class annotations and
     *    other information typically needed for building deserializers
     * @param elementTypeDeserializer If element type needs polymorphic type handling, this is
     *    the type information deserializer to use; should usually be used as is when constructing
     *    array deserializer.
     * @param elementDeserializer Deserializer to use for elements, if explicitly defined (by using
     *    annotations, for exmple). May be null, in which case it should be resolved here (or using
     *    {@link ResolvableDeserializer} callback)
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findCollectionLikeDeserializer(CollectionLikeType type,
            DeserializationConfig config, BeanDescription beanDesc,
            TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
        throws JsonMappingException;

    /**
     * Method called to locate deserializer for specified {@link java.util.Map} type.
     *<p>
     * Deserializer for element type may be passed, if configured explicitly at higher level (by
     * annotations, typically), but usually are not.
     * Type deserializer for element is passed if one is needed based on contextual information
     * (annotations on declared element class; or on field or method type is associated with).
     *<p>
     * Similarly, a {@link KeyDeserializer} may be passed, but this is only done if there is
     * a specific configuration override (annotations) to indicate instance to use.
     * Otherwise null is passed, and key deserializer needs to be obtained later during
     * resolution (using {@link ResolvableDeserializer#resolve}).
     * 
     * @param type Type of {@link java.util.Map} instances to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the enumeration type that contains class annotations and
     *    other information typically needed for building deserializers
     * @param keyDeserializer Key deserializer use, if it is defined via annotations or other configuration;
     *    null if default key deserializer for key type can be used.
     * @param elementTypeDeserializer If element type needs polymorphic type handling, this is
     *    the type information deserializer to use; should usually be used as is when constructing
     *    array deserializer.
     * @param elementDeserializer Deserializer to use for elements, if explicitly defined (by using
     *    annotations, for exmple). May be null, in which case it should be resolved here (or using
     *    {@link ResolvableDeserializer} callback)
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findMapDeserializer(MapType type,
            DeserializationConfig config, BeanDescription beanDesc,
            KeyDeserializer keyDeserializer,
            TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
        throws JsonMappingException;

    /**
     * Method called to locate serializer for specified
     * "Map-like" type (one that acts
     * like {@link java.util.Map} but does not implement it).
     *<p>
     * Deserializer for element type may be passed, if configured explicitly at higher level (by
     * annotations, typically), but usually are not.
     * Type deserializer for element is passed if one is needed based on contextual information
     * (annotations on declared element class; or on field or method type is associated with).
     *<p>
     * Similarly, a {@link KeyDeserializer} may be passed, but this is only done if there is
     * a specific configuration override (annotations) to indicate instance to use.
     * Otherwise null is passed, and key deserializer needs to be obtained later during
     * resolution (using {@link ResolvableDeserializer#resolve}).
     * 
     * @param type Type of {@link java.util.Map} instances to deserialize
     * @param config Configuration in effect
     * @param beanDesc Definition of the enumeration type that contains class annotations and
     *    other information typically needed for building deserializers
     * @param keyDeserializer Key deserializer use, if it is defined via annotations or other configuration;
     *    null if default key deserializer for key type can be used.
     * @param elementTypeDeserializer If element type needs polymorphic type handling, this is
     *    the type information deserializer to use; should usually be used as is when constructing
     *    array deserializer.
     * @param elementDeserializer Deserializer to use for elements, if explicitly defined (by using
     *    annotations, for exmple). May be null, in which case it should be resolved here (or using
     *    {@link ResolvableDeserializer} callback)
     * 
     * @return Deserializer to use for the type; or null if this provider does not know how to construct it
     */
    public JsonDeserializer<?> findMapLikeDeserializer(MapLikeType type,
            DeserializationConfig config, BeanDescription beanDesc,
            KeyDeserializer keyDeserializer,
            TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
        throws JsonMappingException;

    /**
     * Method that may be called to check whether this deserializer provider would provide
     * deserializer for values of given type, without attempting to construct (and possibly
     * fail in some cases) actual deserializer. Mostly needed to support validation
     * of polymorphic type ids.
     *<p>
     * Note: implementations should take care NOT to claim supporting types that they do
     * not recognize as this could to incorrect assumption of safe support by caller.
     *<p>
     * Method added in Jackson 2.13 now that Java 8 default implementations are available
     * for use with interface definitions.
     *
     * @since 2.13
     */
    public default boolean hasDeserializerFor(DeserializationConfig config,
            Class<?> valueType) {
        return false;
    }

    /*
    /**********************************************************************
    /* Helper classes
    /**********************************************************************
     */

    /**
     * Basic {@link Deserializers} implementation that implements all methods but provides
     * no deserializers. Its main purpose is to serve as a base class so that
     * sub-classes only need to override methods they need, as most of the time some
     * of methods are not needed (especially enumeration and array deserializers are
     * very rarely overridden).
     */
    public abstract static class Base
        implements Deserializers
    {
        @Override
        public JsonDeserializer<?> findEnumDeserializer(Class<?> type,
                DeserializationConfig config, BeanDescription beanDesc)
            throws JsonMappingException
        {
            return null;
        }
        
        @Override
        public JsonDeserializer<?> findTreeNodeDeserializer(Class<? extends JsonNode> nodeType,
                DeserializationConfig config, BeanDescription beanDesc)
            throws JsonMappingException
        {
            return null;
        }

        @Override
        public JsonDeserializer<?> findReferenceDeserializer(ReferenceType refType,
                DeserializationConfig config, BeanDescription beanDesc,
                TypeDeserializer contentTypeDeserializer, JsonDeserializer<?> contentDeserializer)
            throws JsonMappingException
        {
            return null;
        }
        
        @Override
        public JsonDeserializer<?> findBeanDeserializer(JavaType type,
                DeserializationConfig config, BeanDescription beanDesc)
            throws JsonMappingException
        {
            return null;
        }
        
        @Override
        public JsonDeserializer<?> findArrayDeserializer(ArrayType type,
                DeserializationConfig config, BeanDescription beanDesc,
                TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
            throws JsonMappingException
        {
            return null;
        }

        @Override
        public JsonDeserializer<?> findCollectionDeserializer(CollectionType type,
                DeserializationConfig config, BeanDescription beanDesc,
                TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
            throws JsonMappingException
        {
            return null;
        }

        @Override
        public JsonDeserializer<?> findCollectionLikeDeserializer(CollectionLikeType type,
                DeserializationConfig config, BeanDescription beanDesc,
                TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
            throws JsonMappingException
        {
            return null;
        }

        @Override
        public JsonDeserializer<?> findMapDeserializer(MapType type,
                DeserializationConfig config, BeanDescription beanDesc,
                KeyDeserializer keyDeserializer,
                TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
            throws JsonMappingException
        {
            return null;
        }

        @Override
        public JsonDeserializer<?> findMapLikeDeserializer(MapLikeType type,
                DeserializationConfig config, BeanDescription beanDesc,
                KeyDeserializer keyDeserializer,
                TypeDeserializer elementTypeDeserializer, JsonDeserializer<?> elementDeserializer)
            throws JsonMappingException
        {
            return null;
        }
    }
}

⏎ com/fasterxml/jackson/databind/deser/Deserializers.java

Or download all of them as a single archive file:

File name: jackson-databind-2.14.0-sources.jar
File size: 1187952 bytes
Release date: 2022-11-05
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