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/ser/std/StdDelegatingSerializer.java

package com.fasterxml.jackson.databind.ser.std;

import com.fasterxml.jackson.core.JsonGenerator;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitable;
import com.fasterxml.jackson.databind.jsonFormatVisitors.JsonFormatVisitorWrapper;
import com.fasterxml.jackson.databind.jsonschema.SchemaAware;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.ContextualSerializer;
import com.fasterxml.jackson.databind.ser.ResolvableSerializer;
import com.fasterxml.jackson.databind.util.ClassUtil;
import com.fasterxml.jackson.databind.util.Converter;

import java.io.IOException;
import java.lang.reflect.Type;

/**
 * Serializer implementation where given Java type is first converted
 * to an intermediate "delegate type" (using a configured
 * {@link Converter}, and then this delegate value is serialized by Jackson.
 *<p>
 * Note that although types may be related, they must not be same; trying
 * to do this will result in an exception.
 *
 * @since 2.1
 */
@SuppressWarnings("serial")
public class StdDelegatingSerializer
    extends StdSerializer<Object>
    implements ContextualSerializer, ResolvableSerializer,
        JsonFormatVisitable, SchemaAware
{
    protected final Converter<Object,?> _converter;

    /**
     * Fully resolved delegate type, with generic information if any available.
     */
    protected final JavaType _delegateType;
    
    /**
     * Underlying serializer for type <code>T</code>.
     */
    protected final JsonSerializer<Object> _delegateSerializer;
    
    /*
    /**********************************************************
    /* Life-cycle
    /**********************************************************
     */

    @SuppressWarnings("unchecked")
    public StdDelegatingSerializer(Converter<?,?> converter)
    {
        super(Object.class);
        _converter = (Converter<Object,?>)converter;
        _delegateType = null;
        _delegateSerializer = null;
    }

    @SuppressWarnings("unchecked")
    public <T> StdDelegatingSerializer(Class<T> cls, Converter<T,?> converter)
    {
        super(cls, false);
        _converter = (Converter<Object,?>)converter;
        _delegateType = null;
        _delegateSerializer = null;
    }
    
    @SuppressWarnings("unchecked")
    public StdDelegatingSerializer(Converter<Object,?> converter,
            JavaType delegateType, JsonSerializer<?> delegateSerializer)
    {
        super(delegateType);
        _converter = converter;
        _delegateType = delegateType;
        _delegateSerializer = (JsonSerializer<Object>) delegateSerializer;
    }

    /**
     * Method used for creating resolved contextual instances. Must be
     * overridden when sub-classing.
     */
    protected StdDelegatingSerializer withDelegate(Converter<Object,?> converter,
            JavaType delegateType, JsonSerializer<?> delegateSerializer)
    {
        ClassUtil.verifyMustOverride(StdDelegatingSerializer.class, this, "withDelegate");
        return new StdDelegatingSerializer(converter, delegateType, delegateSerializer);
    }
    
    /*
    /**********************************************************
    /* Contextualization
    /**********************************************************
     */

    @Override
    public void resolve(SerializerProvider provider) throws JsonMappingException
    {
        if ((_delegateSerializer != null)
                && (_delegateSerializer instanceof ResolvableSerializer)) {
            ((ResolvableSerializer) _delegateSerializer).resolve(provider);
        }
    }

    @Override
    public JsonSerializer<?> createContextual(SerializerProvider provider, BeanProperty property)
        throws JsonMappingException
    {
        JsonSerializer<?> delSer = _delegateSerializer;
        JavaType delegateType = _delegateType;

        if (delSer == null) {
            // Otherwise, need to locate serializer to delegate to. For that we need type information...
            if (delegateType == null) {
                delegateType = _converter.getOutputType(provider.getTypeFactory());
            }
            // 02-Apr-2015, tatu: For "dynamic case", where type is only specified as
            //    java.lang.Object (or missing generic), [databind#731]
            if (!delegateType.isJavaLangObject()) {
                delSer = provider.findValueSerializer(delegateType);
            }
        }
        if (delSer instanceof ContextualSerializer) {
            delSer = provider.handleSecondaryContextualization(delSer, property);
        }
        if (delSer == _delegateSerializer && delegateType == _delegateType) {
            return this;
        }
        return withDelegate(_converter, delegateType, delSer);
    }

    /*
    /**********************************************************
    /* Accessors
    /**********************************************************
     */

    protected Converter<Object, ?> getConverter() {
        return _converter;
    }

    @Override
    public JsonSerializer<?> getDelegatee() {
        return _delegateSerializer;
    }
    
    /*
    /**********************************************************
    /* Serialization
    /**********************************************************
     */

    @Override
    public void serialize(Object value, JsonGenerator gen, SerializerProvider provider) throws IOException
    {
        Object delegateValue = convertValue(value);
        // should we accept nulls?
        if (delegateValue == null) {
            provider.defaultSerializeNull(gen);
            return;
        }
        // 02-Apr-2015, tatu: As per [databind#731] may need to do dynamic lookup
        JsonSerializer<Object> ser = _delegateSerializer;
        if (ser == null) {
            ser = _findSerializer(delegateValue, provider);
        }
        ser.serialize(delegateValue, gen, provider);
    }

    @Override
    public void serializeWithType(Object value, JsonGenerator gen, SerializerProvider provider,
            TypeSerializer typeSer) throws IOException
    {
        // 03-Oct-2012, tatu: This is actually unlikely to work ok... but for now,
        //    let's give it a chance?
        Object delegateValue = convertValue(value);
        JsonSerializer<Object> ser = _delegateSerializer;
        if (ser == null) {
            ser = _findSerializer(value, provider);
        }
        ser.serializeWithType(delegateValue, gen, provider, typeSer);
    }

    @Override
    public boolean isEmpty(SerializerProvider prov, Object value)
    {
        Object delegateValue = convertValue(value);
        if (delegateValue == null) {
            return true;
        }
        if (_delegateSerializer == null) { // best we can do for now, too costly to look up
            return (value == null);
        }
        return _delegateSerializer.isEmpty(prov, delegateValue);
    }

    /*
    /**********************************************************
    /* Schema functionality
    /**********************************************************
     */

    @Override
    public JsonNode getSchema(SerializerProvider provider, Type typeHint)
        throws JsonMappingException
    {
        if (_delegateSerializer instanceof SchemaAware) {
            return ((SchemaAware) _delegateSerializer).getSchema(provider, typeHint);
        }
        return super.getSchema(provider, typeHint);
    }

    @Override
    public JsonNode getSchema(SerializerProvider provider, Type typeHint,
        boolean isOptional) throws JsonMappingException
    {
        if (_delegateSerializer instanceof SchemaAware) {
            return ((SchemaAware) _delegateSerializer).getSchema(provider, typeHint, isOptional);
        }
        return super.getSchema(provider, typeHint);
    }

    @Override
    public void acceptJsonFormatVisitor(JsonFormatVisitorWrapper visitor, JavaType typeHint)
        throws JsonMappingException
    {
        /* 03-Sep-2012, tatu: Not sure if this can be made to really work
         *    properly... but for now, try this:
         */
        // 02-Apr-2015, tatu: For dynamic case, very little we can do
        if (_delegateSerializer != null) {
            _delegateSerializer.acceptJsonFormatVisitor(visitor, typeHint);
        }
    }

    /*
    /**********************************************************
    /* Overridable methods
    /**********************************************************
     */

    /**
     * Method called to convert from source Java value into delegate
     * value (which will be serialized using standard Jackson serializer for delegate type)
     *<P>
     * The default implementation uses configured {@link Converter} to do
     * conversion.
     * 
     * @param value Value to convert
     * 
     * @return Result of conversion
     */
    protected Object convertValue(Object value) {
        return _converter.convert(value);
    }

    /**
     * Helper method used for locating serializer to use in dynamic use case, where
     * actual type value gets converted to is not specified beyond basic
     * {@link java.lang.Object}, and where serializer needs to be located dynamically
     * based on actual value type.
     *
     * @since 2.6
     */
    protected JsonSerializer<Object> _findSerializer(Object value, SerializerProvider serializers)
        throws JsonMappingException
    {
        // NOTE: will NOT call contextualization
        return serializers.findValueSerializer(value.getClass());
    }
}

⏎ com/fasterxml/jackson/databind/ser/std/StdDelegatingSerializer.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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