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/annotation/JsonSerialize.java

package com.fasterxml.jackson.databind.annotation;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.util.Converter;

/**
 * Annotation used for configuring serialization aspects, by attaching
 * to "getter" methods or fields, or to value classes.
 * When annotating value classes, configuration is used for instances
 * of the value class but can be overridden by more specific annotations
 * (ones that attach to methods or fields).
 *<p>
 * An example annotation would be:
 *<pre>
 *  &#64;JsonSerialize(using=MySerializer.class,
 *    as=MySubClass.class,
 *    typing=JsonSerialize.Typing.STATIC
 *  )
 *</pre>
 * (which would be redundant, since some properties block others:
 * specifically, 'using' has precedence over 'as', which has precedence
 * over 'typing' setting)
 */
@Target({ElementType.ANNOTATION_TYPE, ElementType.METHOD, ElementType.FIELD, ElementType.TYPE, ElementType.PARAMETER})
@Retention(RetentionPolicy.RUNTIME)
@com.fasterxml.jackson.annotation.JacksonAnnotation
public @interface JsonSerialize
{
    // // // Annotations for explicitly specifying deserializer

    /**
     * Serializer class to use for
     * serializing associated value. Depending on what is annotated,
     * value is either an instance of annotated class (used globablly
     * anywhere where class serializer is needed); or only used for
     * serializing the value of the property annotated.
     */
    @SuppressWarnings("rawtypes") // to work around JDK8 bug wrt Class-valued annotation properties
    public Class<? extends JsonSerializer> using() default JsonSerializer.None.class;

    /**
     * Serializer class to use for serializing contents (elements
     * of a Collection/array, values of Maps) of annotated property.
     * Can only be used on accessors (methods, fields, constructors), to
     * apply to values of {@link java.util.Map}-valued properties; not
     * applicable for value types used as Array elements
     * or {@link java.util.Collection} and {@link java.util.Map} values.
     */
    @SuppressWarnings("rawtypes") // to work around JDK8 bug wrt Class-valued annotation properties
    public Class<? extends JsonSerializer> contentUsing()
        default JsonSerializer.None.class;

    /**
     * Serializer class to use for deserializing Map keys
     * of annotated property or Map keys of value type so annotated.
     * Can be used both on accessors (methods, fields, constructors), to
     * apply to values of {@link java.util.Map}-valued properties, and
     * on "key" classes, to apply to use of annotated type as
     * {@link java.util.Map} keys (latter starting with Jackson 2.11).
     */
    @SuppressWarnings("rawtypes") // to work around JDK8 bug wrt Class-valued annotation properties
    public Class<? extends JsonSerializer> keyUsing()
        default JsonSerializer.None.class;

    /**
     * Serializer class to use for serializing nulls for properties that
     * are annotated, instead of the
     * default null serializer.
     * Note that using this property when annotation types (classes) has
     * no effect currently (it is possible this could be improved in future).
     * 
     * @since 2.3
     */
    @SuppressWarnings("rawtypes") // to work around JDK8 bug wrt Class-valued annotation properties
    public Class<? extends JsonSerializer> nullsUsing()
        default JsonSerializer.None.class;

    // // // Annotations for type handling, explicit declaration
    // // // (type used for choosing deserializer, if not explicitly
    // // // specified)

    /**
     * Supertype (of declared type, which itself is supertype of runtime type)
     * to use as type when locating serializer to use.
     *<p>
     * Bogus type {@link Void} can be used to indicate that declared
     * type is used as is (i.e. this annotation property has no setting);
     * this since annotation properties are not allowed to have null value.
     *<p>
     * Note: if {@link #using} is also used it has precedence
     * (since it directly specifies
     * serializer, whereas this would only be used to locate the
     * serializer)
     * and value of this annotation property is ignored.
     */
    public Class<?> as() default Void.class;

    /**
     * Concrete type to serialize keys of {@link java.util.Map} as,
     * instead of type otherwise declared.
     * Must be a supertype of declared type; otherwise an exception may be
     * thrown by serializer.
     */
    public Class<?> keyAs() default Void.class;

    /**
     * Concrete type to serialize content value (elements
     * of a Collection/array, values of Maps) as,
     * instead of type otherwise declared.
     * Must be a supertype of declared type; otherwise an exception may be
     * thrown by serializer.
     */
    public Class<?> contentAs() default Void.class;
    
    /**
     * Whether type detection used is dynamic or static: that is,
     * whether actual runtime type is used (dynamic), or just the
     * declared type (static).
     *<p>
     * Note that Jackson 2.3 changed default to <code>DEFAULT_TYPING</code>,
     * which is roughly same as saying "whatever".
     * This is important as it allows avoiding accidental overrides
     * at property level.
     */
    public Typing typing() default Typing.DEFAULT_TYPING;

    // // // Annotations for specifying intermediate Converters (2.2+)
    
    /**
     * Which helper object is to be used to convert type into something
     * that Jackson knows how to serialize; either because base type
     * cannot be serialized easily, or just to alter serialization.
     *
     * @since 2.2
     */
    @SuppressWarnings("rawtypes") // to work around JDK8 bug wrt Class-valued annotation properties
    public Class<? extends Converter> converter() default Converter.None.class;

    /**
     * Similar to {@link #converter}, but used for values of structures types
     * (List, arrays, Maps).
     * Note that this property does NOT have effect when used as Class annotation;
     * it can only be used as property annotation: this because association between
     * container and value types is loose and as such converters seldom make sense
     * for such usage.
     *
     * @since 2.2
     */
    @SuppressWarnings("rawtypes") // to work around JDK8 bug wrt Class-valued annotation properties
    public Class<? extends Converter> contentConverter() default Converter.None.class;
    
    // // // Annotation(s) for inclusion criteria

    /**
     * Which properties of annotated Bean are
     * to be included in serialization (has no effect on other types
     * like enums, primitives or collections).
     * Choices are "all", "properties that have value other than null"
     * and "properties that have non-default value" (i.e. default value
     * being property setting for a Bean constructed with default no-arg
     * constructor, often null).
     *<p>
     * This property has been replaced by special-purpose {@link com.fasterxml.jackson.annotation.JsonInclude}
     * annotation, introduced in Jackson 2.0.
     *<p>
     * Note that Jackson 2.3 changed default to <code>DEFAULT_INCLUSION</code>,
     * which is roughly same as saying "whatever". This is important because
     * it allows hierarchic default values to be used.
     *
     * @deprecated As of Jackson 2.0, this annotation has been replaced
     *    by {@link com.fasterxml.jackson.annotation.JsonInclude}
     */
    @Deprecated
    public Inclusion include() default Inclusion.DEFAULT_INCLUSION;
    
    /*
    /**********************************************************
    /* Value enumerations needed
    /**********************************************************
     */

    /**
     * Enumeration used with {@link JsonSerialize#include} property
     * to define which properties
     * of Java Beans are to be included in serialization
     */
    @Deprecated // since 2.0, marked deprecated in 2.6
    public enum Inclusion
    {
        /**
         * Value that indicates that properties are to be always included,
         * independent of value
         */
        ALWAYS,

        /**
         * Value that indicates that only properties with non-null
         * values are to be included.
         */
        NON_NULL,

        /**
         * Value that indicates that only properties that have values
         * that differ from default settings (meaning values they have
         * when Bean is constructed with its no-arguments constructor)
         * are to be included. Value is generally not useful with
         * {@link java.util.Map}s, since they have no default values;
         * and if used, works same as {@link #ALWAYS}.
         */
        NON_DEFAULT,

        /**
         * Value that indicates that only properties that have values
         * that values that are null or what is considered empty are
         * not to be included.
         * Emptiness is defined for following type:
         *<ul>
         * <li>For {@link java.util.Collection}s and {@link java.util.Map}s,
         *    method <code>isEmpty()</code> is called;
         *   </li>
         * <li>For Java arrays, empty arrays are ones with length of 0
         *   </li>
         * <li>For Java {@link java.lang.String}s, <code>length()</code> is called,
         *   and return value of 0 indicates empty String
         *   </li>
         * </ul>
         *  For other types, non-null values are to be included.
         */
        NON_EMPTY,

        /**
         * Pseudo-value that is used to indicate
         * "use whatever is default used at higher level".
         * 
         * @since 2.3
         */
        DEFAULT_INCLUSION
        ;
    }

    /**
     * Enumeration used with {@link JsonSerialize#typing} property
     * to define whether type detection is based on dynamic runtime
     * type (DYNAMIC) or declared type (STATIC).
     */
    public enum Typing
    {
        /**
         * Value that indicates that the actual dynamic runtime type is to
         * be used.
         */
        DYNAMIC,

        /**
         * Value that indicates that the static declared type is to
         * be used.
         */
        STATIC,
        
        /**
         * Pseudo-value that is used to indicate
         * "use whatever is default used at higher level".
         * 
         * @since 2.3
         */
        DEFAULT_TYPING
        ;
    }
}

⏎ com/fasterxml/jackson/databind/annotation/JsonSerialize.java

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File name: jackson-databind-2.14.0-sources.jar
File size: 1187952 bytes
Release date: 2022-11-05
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