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/module/SimpleDeserializers.java

package com.fasterxml.jackson.databind.module;

import java.util.*;

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

/**
 * Simple implementation {@link Deserializers} which allows registration of
 * deserializers based on raw (type erased class).
 * It can work well for basic bean and scalar type deserializers, but is not
 * a good fit for handling generic types (like {@link Map}s and {@link Collection}s
 * or array types).
 *<p>
 * Unlike {@link SimpleSerializers}, this class does not currently support generic mappings;
 * all mappings must be to exact declared deserialization type.
 */
public class SimpleDeserializers
   extends Deserializers.Base
   implements java.io.Serializable
{
    private static final long serialVersionUID = 1L;

    protected HashMap<ClassKey,JsonDeserializer<?>> _classMappings = null;

    /**
     * Flag to help find "generic" enum deserializer, if one has been registered.
     * 
     * @since 2.3
     */
    protected boolean _hasEnumDeserializer = false;
    
    /*
    /**********************************************************
    /* Life-cycle, construction and configuring
    /**********************************************************
     */
    
    public SimpleDeserializers() { }

    /**
     * @since 2.1
     */
    public SimpleDeserializers(Map<Class<?>,JsonDeserializer<?>> desers) {
        addDeserializers(desers);
    }
    
    public <T> void addDeserializer(Class<T> forClass, JsonDeserializer<? extends T> deser)
    {
        ClassKey key = new ClassKey(forClass);
        if (_classMappings == null) {
            _classMappings = new HashMap<ClassKey,JsonDeserializer<?>>();
        }
        _classMappings.put(key, deser);
        // [Issue#227]: generic Enum deserializer?
        if (forClass == Enum.class) {
            _hasEnumDeserializer = true;
        }
    }

    /**
     * @since 2.1
     */
    @SuppressWarnings("unchecked")
    public void addDeserializers(Map<Class<?>,JsonDeserializer<?>> desers)
    {
        for (Map.Entry<Class<?>,JsonDeserializer<?>> entry : desers.entrySet()) {
            Class<?> cls = entry.getKey();
            // what a mess... nominal generics safety...
            JsonDeserializer<Object> deser = (JsonDeserializer<Object>) entry.getValue();
            addDeserializer((Class<Object>) cls, deser);
        }
    }
    
    /*
    /**********************************************************
    /* Serializers implementation
    /**********************************************************
     */

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

    @Override
    public JsonDeserializer<?> findBeanDeserializer(JavaType type,
            DeserializationConfig config, BeanDescription beanDesc)
        throws JsonMappingException
    {
        return _find(type);
    }

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

    @Override
    public JsonDeserializer<?> findCollectionLikeDeserializer(CollectionLikeType type,
            DeserializationConfig config, BeanDescription beanDesc,
            TypeDeserializer elementTypeDeserializer,
            JsonDeserializer<?> elementDeserializer)
        throws JsonMappingException
    {
        return _find(type);
    }
    
    @Override
    public JsonDeserializer<?> findEnumDeserializer(Class<?> type,
            DeserializationConfig config, BeanDescription beanDesc)
        throws JsonMappingException
    {
        if (_classMappings == null) {
            return null;
        }
        JsonDeserializer<?> deser = _classMappings.get(new ClassKey(type));
        if (deser == null) {
            // 29-Sep-2019, tatu: Not 100% sure this is workable logic but leaving
            //   as is (wrt [databind#2457]. Probably works ok since this covers direct
            //   sub-classes of `Enum`; but even if custom sub-classes aren't, unlikely
            //   mapping for those ever requested for deserialization
            if (_hasEnumDeserializer && type.isEnum()) {
                deser = _classMappings.get(new ClassKey(Enum.class));
            }
        }
        return deser;
    }

    @Override
    public JsonDeserializer<?> findTreeNodeDeserializer(Class<? extends JsonNode> nodeType,
            DeserializationConfig config, BeanDescription beanDesc)
        throws JsonMappingException
    {
        if (_classMappings == null) {
            return null;
        }
        return _classMappings.get(new ClassKey(nodeType));
    }

    @Override
    public JsonDeserializer<?> findReferenceDeserializer(ReferenceType refType,
            DeserializationConfig config, BeanDescription beanDesc,
            TypeDeserializer contentTypeDeserializer, JsonDeserializer<?> contentDeserializer)
        throws JsonMappingException {
        // 21-Oct-2015, tatu: Unlikely this will really get used (reference types need more
        //    work, simple registration probably not sufficient). But whatever.
        return _find(refType);
    }

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

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

    @Override // since 2.11
    public boolean hasDeserializerFor(DeserializationConfig config,
            Class<?> valueType) {
        return (_classMappings != null)
                && _classMappings.containsKey(new ClassKey(valueType));
    }

    private final JsonDeserializer<?> _find(JavaType type) {
        if (_classMappings == null) {
            return null;
        }
        return _classMappings.get(new ClassKey(type.getRawClass()));
    }
}

⏎ com/fasterxml/jackson/databind/module/SimpleDeserializers.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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