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/DatabindContext.java

package com.fasterxml.jackson.databind;

import java.lang.reflect.Type;
import java.util.Locale;
import java.util.TimeZone;

import com.fasterxml.jackson.annotation.*;
import com.fasterxml.jackson.databind.cfg.DatatypeFeature;
import com.fasterxml.jackson.databind.cfg.HandlerInstantiator;
import com.fasterxml.jackson.databind.cfg.MapperConfig;
import com.fasterxml.jackson.databind.introspect.Annotated;
import com.fasterxml.jackson.databind.introspect.ObjectIdInfo;
import com.fasterxml.jackson.databind.jsontype.PolymorphicTypeValidator;
import com.fasterxml.jackson.databind.jsontype.PolymorphicTypeValidator.Validity;
import com.fasterxml.jackson.databind.type.TypeFactory;
import com.fasterxml.jackson.databind.util.ClassUtil;
import com.fasterxml.jackson.databind.util.Converter;

/**
 * Shared base class for {@link DeserializationContext} and
 * {@link SerializerProvider}, context objects passed through data-binding
 * process. Designed so that some of implementations can rely on shared
 * aspects like access to secondary contextual objects like type factories
 * or handler instantiators.
 * 
 * @since 2.2
 */
public abstract class DatabindContext
{
    /**
     * Let's limit length of error messages, for cases where underlying data
     * may be very large -- no point in spamming logs with megabytes of meaningless
     * data.
     *
     * @since 2.9
     */
    private final static int MAX_ERROR_STR_LEN = 500;

    /*
    /**********************************************************
    /* Generic config access
    /**********************************************************
     */

    /**
     * Accessor to currently active configuration (both per-request configs
     * and per-mapper config).
     */
    public abstract MapperConfig<?> getConfig();

    /**
     * Convenience method for accessing serialization view in use (if any); equivalent to:
     *<pre>
     *   getConfig().getAnnotationIntrospector();
     *</pre>
     */
    public abstract AnnotationIntrospector getAnnotationIntrospector();

    /*
    /**********************************************************
    /* Access to specific config settings
    /**********************************************************
     */

    /**
     * Convenience method for checking whether specified Mapper
     * feature is enabled or not.
     * Shortcut for:
     *<pre>
     *  getConfig().isEnabled(feature);
     *</pre>
     */
    public abstract boolean isEnabled(MapperFeature feature);

    /**
     * Method for checking whether specified datatype
     * feature is enabled or not.
     *
     * @since 2.14
     */
    public abstract boolean isEnabled(DatatypeFeature feature);

    /**
     * Convenience method for accessing serialization view in use (if any); equivalent to:
     *<pre>
     *   getConfig().canOverrideAccessModifiers();
     *</pre>
     */
    public abstract boolean canOverrideAccessModifiers();

    /**
     * Accessor for locating currently active view, if any;
     * returns null if no view has been set.
     */
    public abstract Class<?> getActiveView();

    /**
     * @since 2.6
     */
    public abstract Locale getLocale();

    /**
     * @since 2.6
     */
    public abstract TimeZone getTimeZone();

    /**
     * @since 2.7
     */
    public abstract JsonFormat.Value getDefaultPropertyFormat(Class<?> baseType);

    /*
    /**********************************************************
    /* Generic attributes (2.3+)
    /**********************************************************
     */

    /**
     * Method for accessing attributes available in this context.
     * Per-call attributes have highest precedence; attributes set
     * via {@link ObjectReader} or {@link ObjectWriter} have lower
     * precedence.
     * 
     * @param key Key of the attribute to get
     * @return Value of the attribute, if any; null otherwise
     * 
     * @since 2.3
     */
    public abstract Object getAttribute(Object key);

    /**
     * Method for setting per-call value of given attribute.
     * This will override any previously defined value for the
     * attribute within this context.
     * 
     * @param key Key of the attribute to set
     * @param value Value to set attribute to
     * 
     * @return This context object, to allow chaining
     * 
     * @since 2.3
     */
    public abstract DatabindContext setAttribute(Object key, Object value);

    /*
    /**********************************************************
    /* Type instantiation/resolution
    /**********************************************************
     */

    /**
     * Convenience method for constructing {@link JavaType} for given JDK
     * type (usually {@link java.lang.Class})
     */
    public JavaType constructType(Type type) {
        if (type == null) {
            return null;
        }
        return getTypeFactory().constructType(type);
    }

    /**
     * Convenience method for constructing subtypes, retaining generic
     * type parameter (if any).
     *<p>
     * Note: since 2.11 handling has varied a bit across serialization, deserialization.
     */
    public abstract JavaType constructSpecializedType(JavaType baseType, Class<?> subclass);

    /**
     * Lookup method called when code needs to resolve class name from input;
     * usually simple lookup.
     * Note that unlike {@link #resolveAndValidateSubType} this method DOES NOT
     * validate subtype against configured {@link PolymorphicTypeValidator}: usually
     * because such check has already been made.
     *
     * @since 2.9
     */
    public JavaType resolveSubType(JavaType baseType, String subClassName)
        throws JsonMappingException
    {
        // 30-Jan-2010, tatu: Most ids are basic class names; so let's first
        //    check if any generics info is added; and only then ask factory
        //    to do translation when necessary
        if (subClassName.indexOf('<') > 0) {
            // note: may want to try combining with specialization (esp for EnumMap)?
            // 17-Aug-2017, tatu: As per [databind#1735] need to ensure assignment
            //    compatibility -- needed later anyway, and not doing so may open
            //    security issues.
            JavaType t = getTypeFactory().constructFromCanonical(subClassName);
            if (t.isTypeOrSubTypeOf(baseType.getRawClass())) {
                return t;
            }
        } else {
            Class<?> cls;
            try {
                cls =  getTypeFactory().findClass(subClassName);
            } catch (ClassNotFoundException e) { // let caller handle this problem
                return null;
            } catch (Exception e) {
                throw invalidTypeIdException(baseType, subClassName, String.format(
                        "problem: (%s) %s",
                        e.getClass().getName(),
                        ClassUtil.exceptionMessage(e)));
            }
            if (baseType.isTypeOrSuperTypeOf(cls)) {
                return getTypeFactory().constructSpecializedType(baseType, cls);
            }
        }
        throw invalidTypeIdException(baseType, subClassName, "Not a subtype");
    }

    /**
     * Lookup method similar to {@link #resolveSubType} but one that also validates
     * that resulting subtype is valid according to given {@link PolymorphicTypeValidator}.
     *
     * @since 2.10
     */
    public JavaType resolveAndValidateSubType(JavaType baseType, String subClass,
            PolymorphicTypeValidator ptv)
        throws JsonMappingException
    {
        // Off-line the special case of generic (parameterized) type:
        final int ltIndex = subClass.indexOf('<');
        if (ltIndex > 0) {
            return _resolveAndValidateGeneric(baseType, subClass, ptv, ltIndex);
        }
        final MapperConfig<?> config = getConfig();
        PolymorphicTypeValidator.Validity vld = ptv.validateSubClassName(config, baseType, subClass);
        if (vld == Validity.DENIED) {
            return _throwSubtypeNameNotAllowed(baseType, subClass, ptv);
        }
        final Class<?> cls;
        try {
            cls =  getTypeFactory().findClass(subClass);
        } catch (ClassNotFoundException e) { // let caller handle this problem
            return null;
        } catch (Exception e) {
            throw invalidTypeIdException(baseType, subClass, String.format(
                    "problem: (%s) %s",
                    e.getClass().getName(),
                    ClassUtil.exceptionMessage(e)));
        }
        if (!baseType.isTypeOrSuperTypeOf(cls)) {
            return _throwNotASubtype(baseType, subClass);
        }
        final JavaType subType = config.getTypeFactory().constructSpecializedType(baseType, cls);
        // May skip check if type was allowed by subclass name already
        if (vld == Validity.INDETERMINATE) {
            vld = ptv.validateSubType(config, baseType, subType);
            if (vld != Validity.ALLOWED) {
                return _throwSubtypeClassNotAllowed(baseType, subClass, ptv);
            }
        }
        return subType;
    }

    private JavaType _resolveAndValidateGeneric(JavaType baseType, String subClass,
            PolymorphicTypeValidator ptv, int ltIndex)
        throws JsonMappingException
    {
        final MapperConfig<?> config = getConfig();
        // 24-Apr-2019, tatu: Not 100% sure if we should pass name with type parameters
        //    or not, but guessing it's more convenient not to have to worry about it so
        //    strip out
        PolymorphicTypeValidator.Validity vld = ptv.validateSubClassName(config, baseType, subClass.substring(0, ltIndex));
        if (vld == Validity.DENIED) {
            return _throwSubtypeNameNotAllowed(baseType, subClass, ptv);
        }
        JavaType subType = getTypeFactory().constructFromCanonical(subClass);
        if (!subType.isTypeOrSubTypeOf(baseType.getRawClass())) {
            return _throwNotASubtype(baseType, subClass);
        }
        // Unless we were approved already by name, check that actual sub-class acceptable:
        if (vld != Validity.ALLOWED) {
            if (ptv.validateSubType(config, baseType, subType) != Validity.ALLOWED) {
                return _throwSubtypeClassNotAllowed(baseType, subClass, ptv);
            }
        }
        return subType;
    }

    protected <T> T _throwNotASubtype(JavaType baseType, String subType) throws JsonMappingException {
        throw invalidTypeIdException(baseType, subType, "Not a subtype");
    }

    protected <T> T _throwSubtypeNameNotAllowed(JavaType baseType, String subType,
            PolymorphicTypeValidator ptv) throws JsonMappingException {
        throw invalidTypeIdException(baseType, subType,
                "Configured `PolymorphicTypeValidator` (of type "+ClassUtil.classNameOf(ptv)+") denied resolution");
    }

    protected <T> T _throwSubtypeClassNotAllowed(JavaType baseType, String subType,
            PolymorphicTypeValidator ptv) throws JsonMappingException {
        throw invalidTypeIdException(baseType, subType,
                "Configured `PolymorphicTypeValidator` (of type "+ClassUtil.classNameOf(ptv)+") denied resolution");
    }

    /**
     * Helper method for constructing exception to indicate that given type id
     * could not be resolved to a valid subtype of specified base type.
     * Most commonly called during polymorphic deserialization.
     *<p>
     * Note that most of the time this method should NOT be called directly: instead,
     * method <code>handleUnknownTypeId()</code> should be called which will call this method
     * if necessary.
     *
     * @since 2.9
     */
    protected abstract JsonMappingException invalidTypeIdException(JavaType baseType, String typeId,
            String extraDesc);

    public abstract TypeFactory getTypeFactory();

    /*
    /**********************************************************
    /* Helper object construction
    /**********************************************************
     */

    public ObjectIdGenerator<?> objectIdGeneratorInstance(Annotated annotated,
            ObjectIdInfo objectIdInfo)
        throws JsonMappingException
    {
        Class<?> implClass = objectIdInfo.getGeneratorType();
        final MapperConfig<?> config = getConfig();
        HandlerInstantiator hi = config.getHandlerInstantiator();
        ObjectIdGenerator<?> gen = (hi == null) ? null : hi.objectIdGeneratorInstance(config, annotated, implClass);
        if (gen == null) {
            gen = (ObjectIdGenerator<?>) ClassUtil.createInstance(implClass,
                    config.canOverrideAccessModifiers());
        }
        return gen.forScope(objectIdInfo.getScope());
    }

    public ObjectIdResolver objectIdResolverInstance(Annotated annotated, ObjectIdInfo objectIdInfo)
    {
        Class<? extends ObjectIdResolver> implClass = objectIdInfo.getResolverType();
        final MapperConfig<?> config = getConfig();
        HandlerInstantiator hi = config.getHandlerInstantiator();
        ObjectIdResolver resolver = (hi == null) ? null : hi.resolverIdGeneratorInstance(config, annotated, implClass);
        if (resolver == null) {
            resolver = ClassUtil.createInstance(implClass, config.canOverrideAccessModifiers());
        }

        return resolver;
    }

    /**
     * Helper method to use to construct a {@link Converter}, given a definition
     * that may be either actual converter instance, or Class for instantiating one.
     * 
     * @since 2.2
     */
    @SuppressWarnings("unchecked")
    public Converter<Object,Object> converterInstance(Annotated annotated,
            Object converterDef)
        throws JsonMappingException
    {
        if (converterDef == null) {
            return null;
        }
        if (converterDef instanceof Converter<?,?>) {
            return (Converter<Object,Object>) converterDef;
        }
        if (!(converterDef instanceof Class)) {
            throw new IllegalStateException("AnnotationIntrospector returned Converter definition of type "
                    +converterDef.getClass().getName()+"; expected type Converter or Class<Converter> instead");
        }
        Class<?> converterClass = (Class<?>)converterDef;
        // there are some known "no class" markers to consider too:
        if (converterClass == Converter.None.class || ClassUtil.isBogusClass(converterClass)) {
            return null;
        }
        if (!Converter.class.isAssignableFrom(converterClass)) {
            throw new IllegalStateException("AnnotationIntrospector returned Class "
                    +converterClass.getName()+"; expected Class<Converter>");
        }
        final MapperConfig<?> config = getConfig();
        HandlerInstantiator hi = config.getHandlerInstantiator();
        Converter<?,?> conv = (hi == null) ? null : hi.converterInstance(config, annotated, converterClass);
        if (conv == null) {
            conv = (Converter<?,?>) ClassUtil.createInstance(converterClass,
                    config.canOverrideAccessModifiers());
        }
        return (Converter<Object,Object>) conv;
    }

    /*
    /**********************************************************
    /* Error reporting
    /**********************************************************
     */

    /**
     * Helper method called to indicate a generic problem that stems from type
     * definition(s), not input data, or input/output state; typically this
     * means throwing a {@link com.fasterxml.jackson.databind.exc.InvalidDefinitionException}.
     *
     * @since 2.9
     */
    public abstract <T> T reportBadDefinition(JavaType type, String msg) throws JsonMappingException;

    /**
     * @since 2.9
     */
    public <T> T reportBadDefinition(Class<?> type, String msg) throws JsonMappingException {
        return reportBadDefinition(constructType(type), msg);
    }

    /*
    /**********************************************************
    /* Helper methods
    /**********************************************************
     */

    /**
     * @since 2.9
     */
    protected final String _format(String msg, Object... msgArgs) {
        if (msgArgs.length > 0) {
            return String.format(msg, msgArgs);
        }
        return msg;
    }

    /**
     * @since 2.9
     */
    protected final String _truncate(String desc) {
        if (desc == null) {
            return "";
        }
        if (desc.length() <= MAX_ERROR_STR_LEN) {
            return desc;
        }
        return desc.substring(0, MAX_ERROR_STR_LEN) + "]...[" + desc.substring(desc.length() - MAX_ERROR_STR_LEN);
    }

    /**
     * @since 2.9
     */
    protected String _quotedString(String desc) {
        if (desc == null) {
            return "[N/A]";
        }
        // !!! should we quote it? (in case there are control chars, linefeeds)
        return String.format("\"%s\"", _truncate(desc));
    }
    
    /**
     * @since 2.9
     */
    protected String _colonConcat(String msgBase, String extra) {
        if (extra == null) {
            return msgBase;
        }
        return msgBase + ": " + extra;
    }

    /**
     * @since 2.9
     */
    protected String _desc(String desc) {
        if (desc == null) {
            return "[N/A]";
        }
        // !!! should we quote it? (in case there are control chars, linefeeds)
        return _truncate(desc);
    }
}

⏎ com/fasterxml/jackson/databind/DatabindContext.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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