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/EnumSetSerializer.java

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

import java.io.IOException;
import java.util.*;

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;

@SuppressWarnings("serial")
public class EnumSetSerializer
    extends AsArraySerializerBase<EnumSet<? extends Enum<?>>>
{
    /**
     * @since 2.6
     */
    public EnumSetSerializer(JavaType elemType) {
        super(EnumSet.class, elemType, true, null, null);
    }

    public EnumSetSerializer(EnumSetSerializer src,
            BeanProperty property, TypeSerializer vts, JsonSerializer<?> valueSerializer,
            Boolean unwrapSingle) {
        super(src, property, vts, valueSerializer, unwrapSingle);
    }
    
    @Override
    public EnumSetSerializer _withValueTypeSerializer(TypeSerializer vts) {
        // no typing for enums (always "hard" type)
        return this;
    }

    @Override
    public EnumSetSerializer withResolved(BeanProperty property,
            TypeSerializer vts, JsonSerializer<?> elementSerializer,
            Boolean unwrapSingle) {
        return new EnumSetSerializer(this, property, vts, elementSerializer, unwrapSingle);
    }
    
    @Override
    public boolean isEmpty(SerializerProvider prov, EnumSet<? extends Enum<?>> value) {
        return value.isEmpty();
    }

    @Override
    public boolean hasSingleElement(EnumSet<? extends Enum<?>> value) {
        return value.size() == 1;
    }

    @Override
    public final void serialize(EnumSet<? extends Enum<?>> value, JsonGenerator gen,
            SerializerProvider provider) throws IOException
    {
        final int len = value.size();
        if (len == 1) {
            if (((_unwrapSingle == null)
                    && provider.isEnabled(SerializationFeature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED))
                    || (_unwrapSingle == Boolean.TRUE)) {
                serializeContents(value, gen, provider);
                return;
            }
        }
        gen.writeStartArray(value, len);
        serializeContents(value, gen, provider);
        gen.writeEndArray();
    }
    
    @Override
    public void serializeContents(EnumSet<? extends Enum<?>> value, JsonGenerator gen,
            SerializerProvider provider)
        throws IOException
    {
        JsonSerializer<Object> enumSer = _elementSerializer;
        /* Need to dynamically find instance serializer; unfortunately
         * that seems to be the only way to figure out type (no accessors
         * to the enum class that set knows)
         */
        for (Enum<?> en : value) {
            if (enumSer == null) {
                // 12-Jan-2010, tatu: Since enums cannot be polymorphic, let's
                //   not bother with typed serializer variant here
                enumSer = provider.findContentValueSerializer(en.getDeclaringClass(), _property);
            }
            enumSer.serialize(en, gen, provider);
        }
    }
}

⏎ com/fasterxml/jackson/databind/ser/std/EnumSetSerializer.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
Download 

⇒ Jackson Annotations Source Code

⇐ Download and Install Jackson Binary Package

⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library