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/CollectionSerializer.java

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

import java.io.IOException;
import java.util.Collection;
import java.util.Iterator;

import com.fasterxml.jackson.core.*;

import com.fasterxml.jackson.databind.BeanProperty;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.ContainerSerializer;
import com.fasterxml.jackson.databind.ser.impl.PropertySerializerMap;

/**
 * Fallback serializer for cases where Collection is not known to be
 * of type for which more specializer serializer exists (such as
 * index-accessible List).
 * If so, we will just construct an {@link java.util.Iterator}
 * to iterate over elements.
 */
public class CollectionSerializer
    extends AsArraySerializerBase<Collection<?>>
{
    private static final long serialVersionUID = 1L;

    /*
    /**********************************************************
    /* Life-cycle
    /**********************************************************
     */

    /**
     * @since 2.6
     */
    public CollectionSerializer(JavaType elemType, boolean staticTyping, TypeSerializer vts,
            JsonSerializer<Object> valueSerializer) {
        super(Collection.class, elemType, staticTyping, vts, valueSerializer);
    }

    /**
     * @deprecated since 2.6
     */
    @Deprecated // since 2.6
    public CollectionSerializer(JavaType elemType, boolean staticTyping, TypeSerializer vts,
            BeanProperty property, JsonSerializer<Object> valueSerializer) {
        // note: assumption is 'property' is always passed as null
        this(elemType, staticTyping, vts, valueSerializer);
    }
    
    public CollectionSerializer(CollectionSerializer src,
            BeanProperty property, TypeSerializer vts, JsonSerializer<?> valueSerializer,
            Boolean unwrapSingle) {
        super(src, property, vts, valueSerializer, unwrapSingle);
    }
    
    @Override
    public ContainerSerializer<?> _withValueTypeSerializer(TypeSerializer vts) {
        return new CollectionSerializer(this, _property, vts, _elementSerializer, _unwrapSingle);
    }

    @Override
    public CollectionSerializer withResolved(BeanProperty property,
            TypeSerializer vts, JsonSerializer<?> elementSerializer,
            Boolean unwrapSingle) {
        return new CollectionSerializer(this, property, vts, elementSerializer, unwrapSingle);
    }

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

    @Override
    public boolean isEmpty(SerializerProvider prov, Collection<?> value) {
        return value.isEmpty();
    }

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

    /*
    /**********************************************************
    /* Actual serialization
    /**********************************************************
     */

    @Override
    public final void serialize(Collection<?> value, JsonGenerator g, 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, g, provider);
                return;
            }
        }
        g.writeStartArray(value, len);
        serializeContents(value, g, provider);
        g.writeEndArray();
    }
    
    @Override
    public void serializeContents(Collection<?> value, JsonGenerator g, SerializerProvider provider) throws IOException
    {
        g.setCurrentValue(value);
        if (_elementSerializer != null) {
            serializeContentsUsing(value, g, provider, _elementSerializer);
            return;
        }
        Iterator<?> it = value.iterator();
        if (!it.hasNext()) {
            return;
        }
        PropertySerializerMap serializers = _dynamicSerializers;
        final TypeSerializer typeSer = _valueTypeSerializer;

        int i = 0;
        try {
            do {
                Object elem = it.next();
                if (elem == null) {
                    provider.defaultSerializeNull(g);
                } else {
                    Class<?> cc = elem.getClass();
                    JsonSerializer<Object> serializer = serializers.serializerFor(cc);
                    if (serializer == null) {
                        if (_elementType.hasGenericTypes()) {
                            serializer = _findAndAddDynamic(serializers,
                                    provider.constructSpecializedType(_elementType, cc), provider);
                        } else {
                            serializer = _findAndAddDynamic(serializers, cc, provider);
                        }
                        serializers = _dynamicSerializers;
                    }
                    if (typeSer == null) {
                        serializer.serialize(elem, g, provider);
                    } else {
                        serializer.serializeWithType(elem, g, provider, typeSer);
                    }
                }
                ++i;
            } while (it.hasNext());
        } catch (Exception e) {
            wrapAndThrow(provider, e, value, i);
        }
    }

    public void serializeContentsUsing(Collection<?> value, JsonGenerator g, SerializerProvider provider,
            JsonSerializer<Object> ser) throws IOException
    {
        Iterator<?> it = value.iterator();
        if (it.hasNext()) {
            TypeSerializer typeSer = _valueTypeSerializer;
            int i = 0;
            do {
                Object elem = it.next();
                try {
                    if (elem == null) {
                        provider.defaultSerializeNull(g);
                    } else {
                        if (typeSer == null) {
                            ser.serialize(elem, g, provider);
                        } else {
                            ser.serializeWithType(elem, g, provider, typeSer);
                        }
                    }
                    ++i;
                } catch (Exception e) {
                    wrapAndThrow(provider, e, value, i);
                }
            } while (it.hasNext());
        }
    }
}

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