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/IterableSerializer.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.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.ContainerSerializer;

@JacksonStdImpl
@SuppressWarnings("serial")
public class IterableSerializer
    extends AsArraySerializerBase<Iterable<?>>
{
    public IterableSerializer(JavaType elemType, boolean staticTyping,
            TypeSerializer vts) {
        super(Iterable.class, elemType, staticTyping, vts, null);
    }

    public IterableSerializer(IterableSerializer src, BeanProperty property,
            TypeSerializer vts, JsonSerializer<?> valueSerializer,
            Boolean unwrapSingle) {
        super(src, property, vts, valueSerializer, unwrapSingle);
    }

    @Override
    public ContainerSerializer<?> _withValueTypeSerializer(TypeSerializer vts) {
        return new IterableSerializer(this, _property, vts, _elementSerializer, _unwrapSingle);
    }

    @Override
    public IterableSerializer withResolved(BeanProperty property,
            TypeSerializer vts, JsonSerializer<?> elementSerializer,
            Boolean unwrapSingle) {
        return new IterableSerializer(this, property, vts, elementSerializer, unwrapSingle);
    }
    
    @Override
    public boolean isEmpty(SerializerProvider prov, Iterable<?> value) {
        // Not really good way to implement this, but has to do for now:
        return !value.iterator().hasNext();
    }

    @Override
    public boolean hasSingleElement(Iterable<?> value) {
        // we can do it actually (fixed in 2.3.1)
        if (value != null) {
            Iterator<?> it = value.iterator();
            if (it.hasNext()) {
                it.next();
                if (!it.hasNext()) {
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    public final void serialize(Iterable<?> value, JsonGenerator gen,
        SerializerProvider provider)throws IOException
    {
        if (((_unwrapSingle == null) &&
                provider.isEnabled(SerializationFeature.WRITE_SINGLE_ELEM_ARRAYS_UNWRAPPED))
                || (_unwrapSingle == Boolean.TRUE)) {
            if (hasSingleElement(value)) {
                serializeContents(value, gen, provider);
                return;
            }
        }
        gen.writeStartArray(value);
        serializeContents(value, gen, provider);
        gen.writeEndArray();
    }
    
    @Override
    public void serializeContents(Iterable<?> value, JsonGenerator jgen,
        SerializerProvider provider) throws IOException
    {
        Iterator<?> it = value.iterator();
        if (it.hasNext()) {
            final TypeSerializer typeSer = _valueTypeSerializer;
            JsonSerializer<Object> prevSerializer = null;
            Class<?> prevClass = null;
            
            do {
                Object elem = it.next();
                if (elem == null) {
                    provider.defaultSerializeNull(jgen);
                    continue;
                }
                JsonSerializer<Object> currSerializer = _elementSerializer;
                if (currSerializer == null) {
                    // Minor optimization to avoid most lookups:
                    Class<?> cc = elem.getClass();
                    if (cc == prevClass) {
                        currSerializer = prevSerializer;
                    } else {
                        currSerializer = provider.findValueSerializer(cc, _property);
                        prevSerializer = currSerializer;
                        prevClass = cc;
                    }
                }
                if (typeSer == null) {
                    currSerializer.serialize(elem, jgen, provider);
                } else {
                    currSerializer.serializeWithType(elem, jgen, provider, typeSer);
                }
            } while (it.hasNext());
        }
    }
}

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

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⇑⇑ Jackson - Java JSON library