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/introspect/AnnotatedFieldCollector.java

package com.fasterxml.jackson.databind.introspect;

import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
import java.util.*;

import com.fasterxml.jackson.databind.AnnotationIntrospector;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.introspect.ClassIntrospector.MixInResolver;
import com.fasterxml.jackson.databind.type.TypeFactory;
import com.fasterxml.jackson.databind.util.ClassUtil;

public class AnnotatedFieldCollector
    extends CollectorBase
{
    // // // Configuration

    private final TypeFactory _typeFactory;
    private final MixInResolver _mixInResolver;

    /**
     * @since 2.11
     */
    private final boolean _collectAnnotations;

    // // // Collected state

    AnnotatedFieldCollector(AnnotationIntrospector intr,
            TypeFactory types, MixInResolver mixins, boolean collectAnnotations)
    {
        super(intr);
        _typeFactory = types;
        _mixInResolver = (intr == null) ? null : mixins;
        _collectAnnotations = collectAnnotations;
    }

    public static List<AnnotatedField> collectFields(AnnotationIntrospector intr,
            TypeResolutionContext tc,
            MixInResolver mixins, TypeFactory types,
            JavaType type, boolean collectAnnotations)
    {
        return new AnnotatedFieldCollector(intr, types, mixins, collectAnnotations)
                .collect(tc, type);
    }

    List<AnnotatedField> collect(TypeResolutionContext tc, JavaType type)
    {
        Map<String,FieldBuilder> foundFields = _findFields(tc, type, null);
        if (foundFields == null) {
            return Collections.emptyList();
        }
        List<AnnotatedField> result = new ArrayList<>(foundFields.size());
        for (FieldBuilder b : foundFields.values()) {
            result.add(b.build());
        }
        return result;
    }

    private Map<String,FieldBuilder> _findFields(TypeResolutionContext tc,
            JavaType type, Map<String,FieldBuilder> fields)
    {
        // First, a quick test: we only care for regular classes (not interfaces,
        //primitive types etc), except for Object.class. A simple check to rule out
        // other cases is to see if there is a super class or not.
        JavaType parent = type.getSuperClass();
        if (parent == null) {
            return fields;
        }
        final Class<?> cls = type.getRawClass();
        // Let's add super-class' fields first, then ours.
        fields = _findFields(new TypeResolutionContext.Basic(_typeFactory, parent.getBindings()),
                parent, fields);
        for (Field f : cls.getDeclaredFields()) {
            // static fields not included (transients are at this point, filtered out later)
            if (!_isIncludableField(f)) {
                continue;
            }
            // Ok now: we can (and need) not filter out ignorable fields at this point; partly
            // because mix-ins haven't been added, and partly because logic can be done
            // when determining get/settability of the field.
            if (fields == null) {
                fields = new LinkedHashMap<>();
            }
            FieldBuilder b = new FieldBuilder(tc, f);
            if (_collectAnnotations) {
                b.annotations = collectAnnotations(b.annotations, f.getDeclaredAnnotations());
            }
            fields.put(f.getName(), b);
        }
        // And then... any mix-in overrides?
        if ((fields != null) && (_mixInResolver != null)) {
            Class<?> mixin = _mixInResolver.findMixInClassFor(cls);
            if (mixin != null) {
                _addFieldMixIns(mixin, cls, fields);
            }
        }
        return fields;
    }

    /**
     * Method called to add field mix-ins from given mix-in class (and its fields)
     * into already collected actual fields (from introspected classes and their
     * super-classes)
     */
    private void _addFieldMixIns(Class<?> mixInCls, Class<?> targetClass,
            Map<String,FieldBuilder> fields)
    {
        List<Class<?>> parents = ClassUtil.findSuperClasses(mixInCls, targetClass, true);
        for (Class<?> mixin : parents) {
            for (Field mixinField : mixin.getDeclaredFields()) {
                // there are some dummy things (static, synthetic); better ignore
                if (!_isIncludableField(mixinField)) {
                    continue;
                }
                String name = mixinField.getName();
                // anything to mask? (if not, quietly ignore)
                FieldBuilder b = fields.get(name);
                if (b != null) {
                    b.annotations = collectAnnotations(b.annotations, mixinField.getDeclaredAnnotations());
                }
            }
        }
    }

    private boolean _isIncludableField(Field f)
    {
        // Most likely synthetic fields, if any, are to be skipped similar to methods
        if (f.isSynthetic()) {
            return false;
        }
        // Static fields are never included. Transient are (since 2.6), for
        // purpose of propagating removal
        int mods = f.getModifiers();
        if (Modifier.isStatic(mods)) {
            return false;
        }
        return true;
    }

    private final static class FieldBuilder {
        public final TypeResolutionContext typeContext;
        public final Field field;

        public AnnotationCollector annotations;

        public FieldBuilder(TypeResolutionContext tc, Field f) {
            typeContext = tc;
            field = f;
            annotations = AnnotationCollector.emptyCollector();
        }

        public AnnotatedField build() {
            return new AnnotatedField(typeContext, field, annotations.asAnnotationMap());
        }
    }
}

⏎ com/fasterxml/jackson/databind/introspect/AnnotatedFieldCollector.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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