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/VirtualBeanPropertyWriter.java

package com.fasterxml.jackson.databind.ser;

import com.fasterxml.jackson.annotation.JsonInclude;

import com.fasterxml.jackson.core.JsonGenerator;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.cfg.MapperConfig;
import com.fasterxml.jackson.databind.introspect.*;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.impl.PropertySerializerMap;
import com.fasterxml.jackson.databind.util.Annotations;

/**
 * {@link BeanPropertyWriter} implementation used with
 * {@link com.fasterxml.jackson.databind.annotation.JsonAppend}
 * to add "virtual" properties in addition to regular ones.
 * 
 * @since 2.5
 * 
 * @see com.fasterxml.jackson.databind.ser.impl.AttributePropertyWriter
 */
public abstract class VirtualBeanPropertyWriter
    extends BeanPropertyWriter
    implements java.io.Serializable
{
    private static final long serialVersionUID = 1L;

    /**
     * Constructor used by most sub-types.
     */
    protected VirtualBeanPropertyWriter(BeanPropertyDefinition propDef,
            Annotations contextAnnotations, JavaType declaredType)
    {
        this(propDef, contextAnnotations, declaredType, null, null, null,
                propDef.findInclusion());
    }

    /**
     * Constructor that may be used by sub-classes for constructing a "blue-print" instance;
     * one that will only become (or create) actual usable instance when its
     * {@link #withConfig} method is called.
     */
    protected VirtualBeanPropertyWriter() {
        super();
    }

    /**
     * Pass-through constructor that may be used by sub-classes that
     * want full control over implementation.
     */
    protected VirtualBeanPropertyWriter(BeanPropertyDefinition propDef,
            Annotations contextAnnotations, JavaType declaredType,
            JsonSerializer<?> ser, TypeSerializer typeSer, JavaType serType,
            JsonInclude.Value inclusion, Class<?>[] includeInViews)
    {
        super(propDef, propDef.getPrimaryMember(), contextAnnotations, declaredType,
                ser, typeSer, serType,
                _suppressNulls(inclusion), _suppressableValue(inclusion),
                includeInViews);
    }

    @Deprecated // since 2.8
    protected VirtualBeanPropertyWriter(BeanPropertyDefinition propDef,
            Annotations contextAnnotations, JavaType declaredType,
            JsonSerializer<?> ser, TypeSerializer typeSer, JavaType serType,
            JsonInclude.Value inclusion)
    {
        this(propDef, contextAnnotations, declaredType, ser, typeSer, serType, inclusion, null);
    }
    
    protected VirtualBeanPropertyWriter(VirtualBeanPropertyWriter base) {
        super(base);
    }

    protected VirtualBeanPropertyWriter(VirtualBeanPropertyWriter base, PropertyName name) {
        super(base, name);
    }

    protected static boolean _suppressNulls(JsonInclude.Value inclusion) {
        if (inclusion == null) {
            return false;
        }
        JsonInclude.Include incl = inclusion.getValueInclusion();
        return (incl != JsonInclude.Include.ALWAYS) && (incl != JsonInclude.Include.USE_DEFAULTS);
    }

    protected static Object _suppressableValue(JsonInclude.Value inclusion) {
        if (inclusion == null) {
            return false;
        }
        JsonInclude.Include incl = inclusion.getValueInclusion();
        if ((incl == JsonInclude.Include.ALWAYS)
                || (incl == JsonInclude.Include.NON_NULL)
                || (incl == JsonInclude.Include.USE_DEFAULTS)) {
            return null;
        }
        return MARKER_FOR_EMPTY;
    }

    /*
    /**********************************************************
    /* Standard accessor overrides
    /**********************************************************
     */

    @Override
    public boolean isVirtual() { return true; }

    /*
    /**********************************************************
    /* Abstract methods for sub-classes to define
    /**********************************************************
     */

    /**
     * Method called to figure out the value to serialize. For simple sub-types
     * (such as {@link com.fasterxml.jackson.databind.ser.impl.AttributePropertyWriter})
     * this may be one of few methods to define, although more advanced implementations
     * may choose to not even use this method (by overriding {@link #serializeAsField})
     * and define a bogus implementation.
     */
    protected abstract Object value(Object bean, JsonGenerator gen, SerializerProvider prov) throws Exception;

    /**
     * Contextualization method called on a newly constructed virtual bean property.
     * Usually a new intance needs to be created due to finality of some of configuration
     * members; otherwise while recommended, creating a new instance is not strictly-speaking
     * mandatory because calls are made in thread-safe manner, as part of initialization
     * before use.
     *
     * @param config Currenct configuration; guaranteed to be {@link SerializationConfig}
     *   (just not typed since caller does not have dependency to serialization-specific types)
     * @param declaringClass Class that contains this property writer
     * @param propDef Nominal property definition to use
     * @param type Declared type for the property
     */
    public abstract VirtualBeanPropertyWriter withConfig(MapperConfig<?> config,
            AnnotatedClass declaringClass, BeanPropertyDefinition propDef, JavaType type);

    /*
    /**********************************************************
    /* PropertyWriter serialization method overrides
    /**********************************************************
     */
    
    @Override
    public void serializeAsField(Object bean, JsonGenerator gen, SerializerProvider prov) throws Exception
    {
        // NOTE: mostly copied from base class, but off-lined get() access
        final Object value = value(bean, gen, prov);

        if (value == null) {
            if (_nullSerializer != null) {
                gen.writeFieldName(_name);
                _nullSerializer.serialize(null, gen, prov);
            }
            return;
        }
        JsonSerializer<Object> ser = _serializer;
        if (ser == null) {
            Class<?> cls = value.getClass();
            PropertySerializerMap m = _dynamicSerializers;
            ser = m.serializerFor(cls);
            if (ser == null) {
                ser = _findAndAddDynamic(m, cls, prov);
            }
        }
        if (_suppressableValue != null) {
            if (MARKER_FOR_EMPTY == _suppressableValue) {
                if (ser.isEmpty(prov, value)) {
                    return;
                }
            } else if (_suppressableValue.equals(value)) {
                return;
            }
        }
        if (value == bean) { // simple check for direct cycles
            // four choices: exception; handled by call; or pass-through; write null
            if (_handleSelfReference(bean, gen, prov, ser)) {
                return;
            }
        }
        gen.writeFieldName(_name);
        if (_typeSerializer == null) {
            ser.serialize(value, gen, prov);
        } else {
            ser.serializeWithType(value, gen, prov, _typeSerializer);
        }
    }

    // This one's fine as-is from base class
    //public void serializeAsOmittedField(Object bean, JsonGenerator jgen, SerializerProvider prov) throws Exception
    
    @Override
    public void serializeAsElement(Object bean, JsonGenerator gen, SerializerProvider prov)
        throws Exception
    {
        // NOTE: mostly copied from base class, but off-lined get() access
        final Object value = value(bean, gen, prov);

        if (value == null) {
            if (_nullSerializer != null) {
                _nullSerializer.serialize(null, gen, prov);
            } else {
                gen.writeNull();
            }
            return;
        }
        JsonSerializer<Object> ser = _serializer;
        if (ser == null) {
            Class<?> cls = value.getClass();
            PropertySerializerMap map = _dynamicSerializers;
            ser = map.serializerFor(cls);
            if (ser == null) {
                ser = _findAndAddDynamic(map, cls, prov);
            }
        }
        if (_suppressableValue != null) {
            if (MARKER_FOR_EMPTY == _suppressableValue) {
                if (ser.isEmpty(prov, value)) {
                    serializeAsPlaceholder(bean, gen, prov);
                    return;
                }
            } else if (_suppressableValue.equals(value)) {
                serializeAsPlaceholder(bean, gen, prov);
                return;
            }
        }
        if (value == bean) {
            if (_handleSelfReference(bean, gen, prov, ser)) {
                return;
            }
        }
        if (_typeSerializer == null) {
            ser.serialize(value, gen, prov);
        } else {
            ser.serializeWithType(value, gen, prov, _typeSerializer);
        }
    }

    // This one's fine as-is from base class
    //public void serializeAsPlaceholder(Object bean, JsonGenerator jgen, SerializerProvider prov)
}

⏎ com/fasterxml/jackson/databind/ser/VirtualBeanPropertyWriter.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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