Jackson is "the Java JSON library" or "the best JSON parser for Java". Or simply as "JSON for Java".

Jackson Annotations Source Code files are provided in the source packge (jackson-annotations-2.12.4-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Annotations Source Code below:

⏎ com/fasterxml/jackson/databind/deser/impl/FieldProperty.java

package com.fasterxml.jackson.databind.deser.impl;

import java.io.IOException;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;

import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.deser.NullValueProvider;
import com.fasterxml.jackson.databind.deser.SettableBeanProperty;
import com.fasterxml.jackson.databind.introspect.AnnotatedField;
import com.fasterxml.jackson.databind.introspect.AnnotatedMember;
import com.fasterxml.jackson.databind.introspect.BeanPropertyDefinition;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.util.Annotations;
import com.fasterxml.jackson.databind.util.ClassUtil;

/**
 * This concrete sub-class implements property that is set
 * directly assigning to a Field.
 */
public final class FieldProperty
    extends SettableBeanProperty
{
    private static final long serialVersionUID = 1L;

    final protected AnnotatedField _annotated;

    /**
     * Actual field to set when deserializing this property.
     * Transient since there is no need to persist; only needed during
     * construction of objects.
     */
    final protected transient Field _field;

    /**
     * @since 2.9
     */
    final protected boolean _skipNulls;

    public FieldProperty(BeanPropertyDefinition propDef, JavaType type,
            TypeDeserializer typeDeser, Annotations contextAnnotations, AnnotatedField field)
    {
        super(propDef, type, typeDeser, contextAnnotations);
        _annotated = field;
        _field = field.getAnnotated();
        _skipNulls = NullsConstantProvider.isSkipper(_nullProvider);
    }

    protected FieldProperty(FieldProperty src, JsonDeserializer<?> deser,
            NullValueProvider nva) {
        super(src, deser, nva);
        _annotated = src._annotated;
        _field = src._field;
        _skipNulls = NullsConstantProvider.isSkipper(nva);
    }

    protected FieldProperty(FieldProperty src, PropertyName newName) {
        super(src, newName);
        _annotated = src._annotated;
        _field = src._field;
        _skipNulls = src._skipNulls;
    }

    /**
     * Constructor used for JDK Serialization when reading persisted object
     */
    protected FieldProperty(FieldProperty src)
    {
        super(src);
        _annotated = src._annotated;
        Field f = _annotated.getAnnotated();
        if (f == null) {
            throw new IllegalArgumentException("Missing field (broken JDK (de)serialization?)");
        }
        _field = f;
        _skipNulls = src._skipNulls;
    }

    @Override
    public SettableBeanProperty withName(PropertyName newName) {
        return new FieldProperty(this, newName);
    }

    @Override
    public SettableBeanProperty withValueDeserializer(JsonDeserializer<?> deser) {
        if (_valueDeserializer == deser) {
            return this;
        }
        // 07-May-2019, tatu: As per [databind#2303], must keep VD/NVP in-sync if they were
        NullValueProvider nvp = (_valueDeserializer == _nullProvider) ? deser : _nullProvider;
        return new FieldProperty(this, deser, nvp);
    }

    @Override
    public SettableBeanProperty withNullProvider(NullValueProvider nva) {
        return new FieldProperty(this, _valueDeserializer, nva);
    }

    @Override
    public void fixAccess(DeserializationConfig config) {
        ClassUtil.checkAndFixAccess(_field,
                config.isEnabled(MapperFeature.OVERRIDE_PUBLIC_ACCESS_MODIFIERS));
    }

    /*
    /**********************************************************
    /* BeanProperty impl
    /**********************************************************
     */
    
    @Override
    public <A extends Annotation> A getAnnotation(Class<A> acls) {
        return (_annotated == null) ? null : _annotated.getAnnotation(acls);
    }

    @Override public AnnotatedMember getMember() {  return _annotated; }

    /*
    /**********************************************************
    /* Overridden methods
    /**********************************************************
     */

    @Override
    public void deserializeAndSet(JsonParser p,
    		DeserializationContext ctxt, Object instance) throws IOException
    {
        Object value;
        if (p.hasToken(JsonToken.VALUE_NULL)) {
            if (_skipNulls) {
                return;
            }
            value = _nullProvider.getNullValue(ctxt);
        } else if (_valueTypeDeserializer == null) {
            value = _valueDeserializer.deserialize(p, ctxt);
            // 04-May-2018, tatu: [databind#2023] Coercion from String (mostly) can give null
            if (value == null) {
                if (_skipNulls) {
                    return;
                }
                value = _nullProvider.getNullValue(ctxt);
            }
        } else {
            value = _valueDeserializer.deserializeWithType(p, ctxt, _valueTypeDeserializer);
        }
        try {
            _field.set(instance, value);
        } catch (Exception e) {
            _throwAsIOE(p, e, value);
        }
    }

    @Override
    public Object deserializeSetAndReturn(JsonParser p,
    		DeserializationContext ctxt, Object instance) throws IOException
    {
        Object value;
        if (p.hasToken(JsonToken.VALUE_NULL)) {
            if (_skipNulls) {
                return instance;
            }
            value = _nullProvider.getNullValue(ctxt);
        } else if (_valueTypeDeserializer == null) {
            value = _valueDeserializer.deserialize(p, ctxt);
            // 04-May-2018, tatu: [databind#2023] Coercion from String (mostly) can give null
            if (value == null) {
                if (_skipNulls) {
                    return instance;
                }
                value = _nullProvider.getNullValue(ctxt);
            }
        } else {
            value = _valueDeserializer.deserializeWithType(p, ctxt, _valueTypeDeserializer);
        }
        try {
            _field.set(instance, value);
        } catch (Exception e) {
            _throwAsIOE(p, e, value);
        }
        return instance;
    }

    @Override
    public void set(Object instance, Object value) throws IOException
    {
        try {
            _field.set(instance, value);
        } catch (Exception e) {
            // 15-Sep-2015, tatu: How could we get a ref to JsonParser?
            _throwAsIOE(e, value);
        }
    }

    @Override
    public Object setAndReturn(Object instance, Object value) throws IOException
    {
        try {
            _field.set(instance, value);
        } catch (Exception e) {
            // 15-Sep-2015, tatu: How could we get a ref to JsonParser?
            _throwAsIOE(e, value);
        }
        return instance;
    }

    /*
    /**********************************************************
    /* JDK serialization handling
    /**********************************************************
     */

    Object readResolve() {
        return new FieldProperty(this);
    }
}

⏎ com/fasterxml/jackson/databind/deser/impl/FieldProperty.java

 

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