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-2.12.4-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Databind Source Code below:

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

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

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

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.*;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.util.Annotations;

/**
 * This concrete sub-class implements property that is set
 * using regular "setter" method.
 */
public final class MethodProperty
    extends SettableBeanProperty
{
    private static final long serialVersionUID = 1;

    protected final AnnotatedMethod _annotated;
    
    /**
     * Setter method for modifying property value; used for
     * "regular" method-accessible properties.
     */
    protected final transient Method _setter;

    /**
     * @since 2.9
     */
    final protected boolean _skipNulls;
    
    public MethodProperty(BeanPropertyDefinition propDef,
            JavaType type, TypeDeserializer typeDeser,
            Annotations contextAnnotations, AnnotatedMethod method)
    {
        super(propDef, type, typeDeser, contextAnnotations);
        _annotated = method;
        _setter = method.getAnnotated();
        _skipNulls = NullsConstantProvider.isSkipper(_nullProvider);
    }

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

    protected MethodProperty(MethodProperty src, PropertyName newName) {
        super(src, newName);
        _annotated = src._annotated;
        _setter = src._setter;
        _skipNulls = src._skipNulls;
    }

    /**
     * Constructor used for JDK Serialization when reading persisted object
     */
    protected MethodProperty(MethodProperty src, Method m) {
        super(src);
        _annotated = src._annotated;
        _setter = m;
        _skipNulls = src._skipNulls;
    }

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

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

    @Override
    public void fixAccess(DeserializationConfig config) {
        _annotated.fixAccess(
                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 {
            _setter.invoke(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 {
            Object result = _setter.invoke(instance, value);
            return (result == null) ? instance : result;
        } catch (Exception e) {
            _throwAsIOE(p, e, value);
            return null;
        }
    }

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

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

    Object readResolve() {
        return new MethodProperty(this, _annotated.getAnnotated());
    }
}

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

 

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