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

Jackson also allows you to parse or generate XML messages with the Jackson Dataformat XML Extension.

Jackson Dataformat XML Source Code files are provided in the source packge (jackson-dataformat-xml-2.14.0-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Dataformat XML Source Code below:

⏎ com/fasterxml/jackson/dataformat/xml/ser/XmlBeanSerializerBase.java

package com.fasterxml.jackson.dataformat.xml.ser;

import java.io.IOException;
import java.util.BitSet;
import java.util.Set;

import javax.xml.namespace.QName;

import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.SerializerProvider;
import com.fasterxml.jackson.databind.jsontype.TypeSerializer;
import com.fasterxml.jackson.databind.ser.BeanPropertyWriter;
import com.fasterxml.jackson.databind.ser.PropertyFilter;
import com.fasterxml.jackson.databind.ser.impl.ObjectIdWriter;
import com.fasterxml.jackson.databind.ser.impl.WritableObjectId;
import com.fasterxml.jackson.databind.ser.std.BeanSerializerBase;
import com.fasterxml.jackson.databind.util.NameTransformer;
import com.fasterxml.jackson.dataformat.xml.util.XmlInfo;

/**
 * Specific sub-class of {@link BeanSerializerBase} needed to take care
 * of some xml-specific aspects, such as distinction between attributes
 * and elements.
 */
@SuppressWarnings("serial")
public abstract class XmlBeanSerializerBase extends BeanSerializerBase
{
    /**
     * Marker used for storing associated internal data with {@link BeanPropertyWriter}
     * instances; to mark instances that are to be written out as attributes.
     * Created as separate non-interned String to ensure there are no collisions.
     */
    public final static String KEY_XML_INFO = new String("xmlInfo");

    /**
     * Number of attributes to write; these will have been ordered to be the first
     * properties to write.
     */
    protected final int _attributeCount;

    /**
     * Index of "text value" property we have, if any; can have at most
     * one such property.
     */
    protected final int _textPropertyIndex;

    /**
     * Array that contains namespace URIs associated with properties, if any;
     * null if no namespace definitions have been assigned
     */
    protected final QName[] _xmlNames;

    /**
     * Optional set of indexes of properties that should be serialized as CDATA,
     * instead of regular XML text segment. Left as null in cases where none of
     * element values are to be written in such a way.
     */
    protected final BitSet _cdata;
    
    public XmlBeanSerializerBase(BeanSerializerBase src)
    {
        super(src);

        // Then make sure attributes are sorted before elements, keep track
        // of how many there are altogether
        int attrCount = 0;
        for (BeanPropertyWriter bpw : _props) {
            if (_isAttribute(bpw)) { // Yup: let's build re-ordered list then
                attrCount = _orderAttributesFirst(_props, _filteredProps);
                break;
            }
        }
        _attributeCount = attrCount;

        // also: pre-compute need, if any, for CDATA handling:
        BitSet cdata = null;
        for (int i = 0, len = _props.length; i < len; ++i) {
            BeanPropertyWriter bpw = _props[i];
            if (_isCData(bpw)) {
                if (cdata == null) {
                    cdata = new BitSet(len);
                }
                cdata.set(i);
            }
        }
        _cdata = cdata;
        
        // And then collect namespace information
        _xmlNames = new QName[_props.length];
        int textIndex = -1;
        for (int i = 0, len = _props.length; i < len; ++i) {
            BeanPropertyWriter bpw = _props[i];
            XmlInfo info = (XmlInfo) bpw.getInternalSetting(KEY_XML_INFO);
            String ns = null;
            if (info != null) {
                ns = info.getNamespace();
                if (textIndex < 0 && info.isText()) {
                    textIndex = i;
                }
            }
            _xmlNames[i] = new QName((ns == null) ? "" : ns, bpw.getName());
        }
        _textPropertyIndex = textIndex;
    }

    protected XmlBeanSerializerBase(XmlBeanSerializerBase src, ObjectIdWriter objectIdWriter)
    {
        super(src, objectIdWriter);
        _attributeCount = src._attributeCount;
        _textPropertyIndex = src._textPropertyIndex;
        _xmlNames = src._xmlNames;
        _cdata = src._cdata;
    }

    protected XmlBeanSerializerBase(XmlBeanSerializerBase src, ObjectIdWriter objectIdWriter, Object filterId)
    {
        super(src, objectIdWriter, filterId);
        _attributeCount = src._attributeCount;
        _textPropertyIndex = src._textPropertyIndex;
        _xmlNames = src._xmlNames;
        _cdata = src._cdata;
    }

    protected XmlBeanSerializerBase(XmlBeanSerializerBase src,
            Set<String> toIgnore, Set<String> toInclude)
    {
        super(src, toIgnore, toInclude);
        _attributeCount = src._attributeCount;
        _textPropertyIndex = src._textPropertyIndex;
        _xmlNames = src._xmlNames;
        _cdata = src._cdata;
    }
    
    public XmlBeanSerializerBase(XmlBeanSerializerBase src, NameTransformer transformer)
    {
        super(src, transformer);
        _attributeCount = src._attributeCount;
        _textPropertyIndex = src._textPropertyIndex;
        _xmlNames = src._xmlNames;
        _cdata = src._cdata;
    }

    // @since 2.11.1
    protected XmlBeanSerializerBase(XmlBeanSerializerBase src,
            BeanPropertyWriter[] properties, BeanPropertyWriter[] filteredProperties) {
        super(src, properties, filteredProperties);
        _attributeCount = src._attributeCount;
        _textPropertyIndex = src._textPropertyIndex;
        _xmlNames = src._xmlNames;
        _cdata = src._cdata;
    }

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

    /**
     * Main serialization method needs to be overridden to allow XML-specific
     * extra handling, such as indication of whether to write attributes or
     * elements.
     */
    @Override
    protected void serializeFields(Object bean, JsonGenerator gen0, SerializerProvider provider)
        throws IOException
    {
        // 19-Aug-2013, tatu: During 'convertValue()', need to skip
        if (!(gen0 instanceof ToXmlGenerator)) {
            super.serializeFields(bean, gen0, provider);
            return;
        }
        final ToXmlGenerator xgen = (ToXmlGenerator) gen0;
        final BeanPropertyWriter[] props;
        if (_filteredProps != null && provider.getActiveView() != null) {
            props = _filteredProps;
        } else {
            props = _props;
        }

        final int attrCount = _attributeCount;
        final boolean isAttribute = xgen._nextIsAttribute;
        if (attrCount > 0) {
            xgen.setNextIsAttribute(true);
        }
        final int textIndex = _textPropertyIndex;
        final QName[] xmlNames = _xmlNames;
        int i = 0;
        final BitSet cdata = _cdata;

        try {
            for (final int len = props.length; i < len; ++i) {
                // 28-jan-2014, pascal: we don't want to reset the attribute flag if we are an unwrapping serializer 
                // that started with nextIsAttribute to true because all properties should be unwrapped as attributes too.
                if (i == attrCount && !(isAttribute && isUnwrappingSerializer())) {
                    xgen.setNextIsAttribute(false);
                }
                // also: if this is property to write as text ("unwrap"), need to:
                if (i == textIndex) {
                    xgen.setNextIsUnwrapped(true);
                }
                xgen.setNextName(xmlNames[i]);
                BeanPropertyWriter prop = props[i];
                if (prop != null) { // can have nulls in filtered list
                    if ((cdata != null) && cdata.get(i)) {
                        xgen.setNextIsCData(true);
                        prop.serializeAsField(bean, xgen, provider);
                        xgen.setNextIsCData(false);
                    } else {
                        prop.serializeAsField(bean, xgen, provider);
                    }
                }
                // Reset to avoid next value being written as unwrapped, 
                // for example when property is suppressed
                if (i == textIndex) {
                    xgen.setNextIsUnwrapped(false);
                }
            }
            if (_anyGetterWriter != null) {
                // For [#117]: not a clean fix, but with @JsonTypeInfo, we'll end up
                // with accidental attributes otherwise
                xgen.setNextIsAttribute(false);
                _anyGetterWriter.getAndSerialize(bean, xgen, provider);
            }
        } catch (Exception e) {
            String name = (i == props.length) ? "[anySetter]" : props[i].getName();
            wrapAndThrow(provider, e, bean, name);
        } catch (StackOverflowError e) { // Bit tricky, can't do more calls as stack is full; so:
            JsonMappingException mapE = JsonMappingException.from(gen0,
                    "Infinite recursion (StackOverflowError)");
            String name = (i == props.length) ? "[anySetter]" : props[i].getName();
            mapE.prependPath(new JsonMappingException.Reference(bean, name));
            throw mapE;
        }
    }

    @Override
    protected void serializeFieldsFiltered(Object bean, JsonGenerator gen0,
            SerializerProvider provider)
        throws IOException
    {
        // 19-Aug-2013, tatu: During 'convertValue()', need to skip
        if (!(gen0 instanceof ToXmlGenerator)) {
            super.serializeFieldsFiltered(bean, gen0, provider);
            return;
        }
        
        final ToXmlGenerator xgen = (ToXmlGenerator) gen0;
        
        final BeanPropertyWriter[] props;
        if (_filteredProps != null && provider.getActiveView() != null) {
            props = _filteredProps;
        } else {
            props = _props;
        }
        final PropertyFilter filter = findPropertyFilter(provider, _propertyFilterId, bean);
        // better also allow missing filter actually..
        if (filter == null) {
            serializeFields(bean, gen0, provider);
            return;
        }

        final boolean isAttribute = xgen._nextIsAttribute;
        final int attrCount = _attributeCount;
        if (attrCount > 0) {
            xgen.setNextIsAttribute(true);
        }
        final int textIndex = _textPropertyIndex;
        final QName[] xmlNames = _xmlNames;
        final BitSet cdata = _cdata;

        int i = 0;
        try {
            for (final int len = props.length; i < len; ++i) {
                // 28-jan-2014, pascal: we don't want to reset the attribute flag if we are an unwrapping serializer 
                // that started with nextIsAttribute to true because all properties should be unwrapped as attributes too.
                if (i == attrCount && !(isAttribute && isUnwrappingSerializer())) {
                    xgen.setNextIsAttribute(false);
                }
                // also: if this is property to write as text ("unwrap"), need to:
                if (i == textIndex) {
                    xgen.setNextIsUnwrapped(true);
                }
                xgen.setNextName(xmlNames[i]);
                BeanPropertyWriter prop = props[i];
                if (prop != null) { // can have nulls in filtered list
                    if ((cdata != null) && cdata.get(i)) {
                        xgen.setNextIsCData(true);
                        filter.serializeAsField(bean, xgen, provider, prop);
                        xgen.setNextIsCData(false);
                    } else {
                        filter.serializeAsField(bean, xgen, provider, prop);
                    }
                }
            }
            if (_anyGetterWriter != null) {
                // For [#117]: not a clean fix, but with @JsonTypeInfo, we'll end up
                // with accidental attributes otherwise
                xgen.setNextIsAttribute(false);
                // 24-Jul-2019, tatu: Fixed for [dataformat-xml#351]
                _anyGetterWriter.getAndFilter(bean, xgen, provider, filter);
            }
        } catch (Exception e) {
            String name = (i == props.length) ? "[anySetter]" : props[i].getName();
            wrapAndThrow(provider, e, bean, name);
        } catch (StackOverflowError e) {
            JsonMappingException mapE = JsonMappingException.from(gen0, "Infinite recursion (StackOverflowError)", e);
            String name = (i == props.length) ? "[anySetter]" : props[i].getName();
            mapE.prependPath(new JsonMappingException.Reference(bean, name));
            throw mapE;
        }
    }
    
    @Override
    public void serializeWithType(Object bean, JsonGenerator gen, SerializerProvider provider,
            TypeSerializer typeSer)
        throws IOException
    {
        if (_objectIdWriter != null) {
            _serializeWithObjectId(bean, gen, provider, typeSer);
            return;
        }
        /* Ok: let's serialize type id as attribute, but if (and only if!)
         * we are using AS_PROPERTY
         */
        if (typeSer.getTypeInclusion() == JsonTypeInfo.As.PROPERTY) {
            ToXmlGenerator xgen = (ToXmlGenerator)gen;
            xgen.setNextIsAttribute(true);
            super.serializeWithType(bean, gen, provider, typeSer);
            if (_attributeCount == 0) { // if no attributes, need to reset
                xgen.setNextIsAttribute(false);
            }
        } else {
            super.serializeWithType(bean, gen, provider, typeSer);
        }
    }
    
    @Override
    protected void _serializeObjectId(Object bean, JsonGenerator gen, SerializerProvider provider,
            TypeSerializer typeSer, WritableObjectId objectId) throws IOException
    {
        // Ok: let's serialize type id as attribute, but if (and only if!) we are using AS_PROPERTY
        if (typeSer.getTypeInclusion() == JsonTypeInfo.As.PROPERTY) {
            ToXmlGenerator xgen = (ToXmlGenerator)gen;
            xgen.setNextIsAttribute(true);
            super._serializeObjectId(bean, gen, provider, typeSer, objectId);
            if (_attributeCount == 0) { // if no attributes, need to reset
                xgen.setNextIsAttribute(false);
            }
        } else {
            super._serializeObjectId(bean, gen, provider, typeSer, objectId);
        }
    }

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

    protected static boolean _isAttribute(BeanPropertyWriter bpw)
    {
        XmlInfo info = (XmlInfo) bpw.getInternalSetting(KEY_XML_INFO);
        return (info != null) && info.isAttribute();
    }

    protected static boolean _isCData(BeanPropertyWriter bpw)
    {
        XmlInfo info = (XmlInfo) bpw.getInternalSetting(KEY_XML_INFO);
        return (info != null) && info.isCData();
    }

    /**
     * Method for re-sorting lists of bean properties such that attributes are strictly
     * written before elements.
     */
    protected static int _orderAttributesFirst(BeanPropertyWriter[] properties,
            BeanPropertyWriter[] filteredProperties)
    {
        int attrCount = 0;

        for (int i = 0, len = properties.length; i < len; ++i) {
            BeanPropertyWriter bpw = properties[i];
            
            if (!_isAttribute(bpw)) {
                continue;
            }
            
            // Move attribute a few places down as necessary
            int moveBy = i - attrCount;
            if (moveBy > 0) {
                System.arraycopy(properties, attrCount, properties, attrCount + 1, moveBy);
                properties[attrCount] = bpw;
                if (filteredProperties != null) {
                    BeanPropertyWriter fbpw = filteredProperties[i];
                    System.arraycopy(filteredProperties, attrCount, filteredProperties, attrCount+1, moveBy);
                    filteredProperties[attrCount] = fbpw;
                }
            }
            ++attrCount;
        }
        return attrCount;
    }
}

⏎ com/fasterxml/jackson/dataformat/xml/ser/XmlBeanSerializerBase.java

Or download all of them as a single archive file:

File name: jackson-dataformat-xml-2.14.0-sources.jar
File size: 98015 bytes
Release date: 2022-11-05
Download 

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