How to deserialize same name node into two different classes with XStream

How to deserialize same name node into two different classes with XStream - java

I have a problem while deserializing an XML file.
My file is like:
<mission>
<branch>
<alternative uid="0" type="ALT_MONITOR"/>
<alternative uid="1" type="ALT_IF" condition="i==10"/>
</branch>
</mission>
I have a class called Alternative:
public abtract class Alternative {
#XStreamAsAttribute
public int uid;
#XStreamAsAttribute
public String type;
}
This class is extended by two other class:
#XStreamAlias("alternative")
public class AlternativeA extends Alternative {
}
#XStreamAlias("alternative")
public class AlternativeB extends Alternative {
#XStreamAsAttribute
public String condition;
}
And then i have an xStream converter :
public class AlternativeConverter extends ReflectionConverter {
public AlternativesConverter(Mapper mapper, ReflectionProvider reflectionProvider) {
super(mapper, reflectionProvider);
}
#Override
public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
if (reader.getAttribute("condition") != null) {
AlternativeA alternativeA = new AlternativeA();
alternativeA.setUid(Integer.parseInt(reader.getAttribute("uid")));
alternativeA.setCondition(reader.getAttribute("condition"));
return super.doUnmarshal(alternativeA, reader, context);
}else {
AlternativeB alternativeB = new AlternativeB();
alternativeB.setUid(Integer.parseInt(reader.getAttribute("uid")));
return super.doUnmarshal(alternativeB, reader, context);
}
}
#SuppressWarnings("unchecked")
#Override
public boolean canConvert(Class clazz) {
return Alternative.class.isAssignableFrom(clazz);
}
}
But when i try to convert the xml to an object. When it reaches the alternative with a condition it throws an exception :
Cannot convert type AlternativeB to type AlternativeA
Do any of you have an idea or an int on what could cause that error ?
Thank you in advance.

Java:
package de.mosst.spielwiese;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import org.junit.Test;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.annotations.XStreamAlias;
import com.thoughtworks.xstream.annotations.XStreamAsAttribute;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.UnmarshallingContext;
import com.thoughtworks.xstream.converters.reflection.ReflectionConverter;
import com.thoughtworks.xstream.converters.reflection.ReflectionProvider;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.mapper.Mapper;
import lombok.Data;
public class XStreamMultiClassesTest {
#Test
public void smokeTest() {
InputStream file = XStreamMultiClassesTest.class.getResourceAsStream("XStreamMultiClassesTest.xml");
XStream xStream = new XStream();
xStream.ignoreUnknownElements();
xStream.processAnnotations(Mission.class);
xStream.processAnnotations(Alternative.class);
Converter converter = new AlternativeConverter(xStream.getMapper(), xStream.getReflectionProvider());
xStream.registerConverter(converter);
Mission mission = (Mission) xStream.fromXML(file);
System.out.println(mission);
mission.branch.forEach(a -> {
System.out.println(a.getClass());
if (a instanceof AlternativeA) {
System.out.println("- condition: " + ((AlternativeA) a).condition);
}
});
}
public class AlternativeConverter extends ReflectionConverter {
public AlternativeConverter(Mapper mapper, ReflectionProvider reflectionProvider) {
super(mapper, reflectionProvider);
}
#Override
public Object unmarshal(HierarchicalStreamReader reader, UnmarshallingContext context) {
Alternative alternative = null;
if (reader.getAttribute("condition") != null) {
alternative = new AlternativeA();
((AlternativeA) alternative).condition = reader.getAttribute("condition");
} else {
alternative = new AlternativeB();
}
alternative.uid = Integer.parseInt(reader.getAttribute("uid"));
return super.doUnmarshal(alternative, reader, context);
}
#Override
public boolean canConvert(#SuppressWarnings("rawtypes") Class clazz) {
return Alternative.class.isAssignableFrom(clazz);
}
}
#XStreamAlias("mission")
#Data
class Mission {
public List<Alternative> branch = new ArrayList<>();
}
#XStreamAlias("alternative")
#Data
abstract class Alternative {
#XStreamAsAttribute
public int uid;
#XStreamAsAttribute
public String type;
}
class AlternativeA extends Alternative {
public String condition;
}
class AlternativeB extends Alternative {
}
}
XML:
<?xml version="1.0" encoding="UTF-8"?>
<mission>
<branch>
<alternative uid="0" type="ALT_MONITOR" />
<alternative uid="1" type="ALT_IF" condition="i==10" />
</branch>
</mission>

Related

FasterXml - JsonSerializer HashMap

I'm using jackson-databind version 2.12.3 to serialize the return of an object that should return like this:
{
"field1":"value1",
"field2":"value2",
"links":{
"field":{
"href":"/link"
},
"test":{
"href":"/test"
}
}
}
My classes are these:
public class HrefType {
private String href = null;
...
}
public class Link extends HashMap<String, HrefType> {
private HrefType field = null;
...
}
public class MyObject {
private String field1 = null;
private String field2 = null;
private Link links = null;
...
}
The return is myObject:
MyObject myObject = new MyObject();
myObject.setField1("value1");
myObject.setField2("value2");
Link link = new Link();
link.setField(new HrefType().href("/link"));
link.put("test",new HrefType().href("/test"));
myObject.setLinks(link);
However with the default ObjectMapper the "link.setField" is ignored and the returned json is:
{
"field1":"value1",
"field2":"value2",
"links":{
"test":{
"href":"/test"
}
}
}
I tried doing some tests with JsonSerializer but couldn't do something generic for all classes that extend HashMap (these classes are generated from BerlinGroup's PSD2 YAML, so I wouldn't want to change the generated class).
Is there a generic way to do it, or should I make a serialize class for each class that extends the HashMap?

Composition
First of all, I suggest you use composition instead of inheritance in this particular case. Your code will look like the next:
private class Link {
private final HrefType field;
private final HashMap<String, HrefType> test;
public Link(HrefType field) {
this.field = field;
}
public HrefType getField() {
return field;
}
public HashMap<String, HrefType> getTest() {
return test;
}
}
And serialization will work fine, as expected.
Serializer
But in case, if you can't change the original code, you might to write your own StdSerializer. For example:
private class LinkSerializer extends StdSerializer<Link> {
public LinkSerializer() {
super(Link.class);
}
#Override
public void serialize(Link link, JsonGenerator jsonGenerator, SerializerProvider serializerProvider) throws IOException {
jsonGenerator.writeStartObject();
final HrefType field = link.getField();
jsonGenerator.writeObjectField("field", field);
jsonGenerator.writeObjectField("test", new HashMap<>(link));
jsonGenerator.writeEndObject();
}
}
And declare it over your Link class:
#JsonSerialize(using = LinkSerializer.class)
private static class Link extends HashMap<String, HrefType> {
private final HrefType field;
public Link(HrefType field) {
this.field = field;
}
public HrefType getField() {
return field;
}
}

based on this answer I developed this generic method of making for all objects that extend a Map:
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.Map;
import org.springframework.util.ReflectionUtils;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.databind.JsonSerializer;
import com.fasterxml.jackson.databind.SerializerProvider;
public class MyClassSerializer extends JsonSerializer<Object> {
private final JsonSerializer<Object> defaultSerializer;
public MyClassSerializer(JsonSerializer<Object> defaultSerializer) {
this.defaultSerializer = (defaultSerializer);
}
#SuppressWarnings({ "unchecked", "rawtypes" })
#Override
public void serialize(Object src, JsonGenerator gen, SerializerProvider provider) throws IOException {
Field[] fields = src.getClass().getDeclaredFields();
for (Field field : fields) {
try {
boolean fieldAccessible = field.isAccessible();
field.setAccessible(true);
Object object = ReflectionUtils.getField(field, src);
if (object != null && object instanceof Map) {
Field[] fieldsMap = object.getClass().getDeclaredFields();
Map map = (Map) object;
for (Field fieldMap : fieldsMap) {
boolean fieldMapAccessible = fieldMap.isAccessible();
fieldMap.setAccessible(true);
Object fieldObject = ReflectionUtils.getField(fieldMap, object);
if (fieldObject != null) {
map.put(fieldMap.getName(), fieldObject);
}
fieldMap.setAccessible(fieldMapAccessible);
}
}
field.setAccessible(fieldAccessible);
} catch (Exception e) {
e.printStackTrace();
}
}
defaultSerializer.serialize(src, gen, provider);
}
#Override
public Class<Object> handledType() {
return Object.class;
}
}
which goes through all fields, when I find one that extends from a Map I go through all the fields of this one and add it to the Map ignoring the object's fields, so the Serializer works perfectly.
EDIT: to Deserializer properly I do this:
import java.io.IOException;
import java.lang.reflect.Field;
import java.util.Map;
import org.springframework.util.ReflectionUtils;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonDeserializer;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.deser.ResolvableDeserializer;
#SuppressWarnings("rawtypes")
public class MyClassDeserializer extends JsonDeserializer implements ResolvableDeserializer {
private JsonDeserializer defaultDeserializer;
protected MyClassDeserializer(JsonDeserializer deserializer) {
this.defaultDeserializer = deserializer;
}
#SuppressWarnings("unchecked")
#Override
public Object deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
Object obj = defaultDeserializer.deserialize(p, ctxt);
Field[] fields = obj.getClass().getDeclaredFields();
for (Field field : fields) {
try {
boolean fieldAccessible = field.isAccessible();
field.setAccessible(true);
Object object = ReflectionUtils.getField(field, obj);
if (object != null && object instanceof Map) {
Field[] fieldsMap = object.getClass().getDeclaredFields();
Map map = (Map) object;
for (Object key : map.keySet()) {
for (Field fieldMap : fieldsMap) {
if (fieldMap.getName().equals((String) key)) {
if (fieldMap.getName().equalsIgnoreCase("serialVersionUID")) {
continue;
}
boolean fieldMapAccessible = fieldMap.isAccessible();
fieldMap.setAccessible(true);
Object fieldObject = ReflectionUtils.getField(fieldMap, object);
if (fieldObject == null) {
fieldMap.set(object, map.get(key));
map.replace(key, null);
}
fieldMap.setAccessible(fieldMapAccessible);
}
}
}
Object[] keys = map.keySet().toArray();
for (int i = 0; i < keys.length; i++) {
if(map.get(keys[i])==null) {
map.remove(keys[i]);
}
}
}
field.setAccessible(fieldAccessible);
} catch (Exception e) {
e.printStackTrace();
}
}
return obj;
}
#Override
public void resolve(DeserializationContext ctxt) throws JsonMappingException {
((ResolvableDeserializer) defaultDeserializer).resolve(ctxt);
}
}

Different fields with same JsonProperty attribute

Is it possible to have something like below while serializing a JSON in the same class
#JsonProperty("stats")
private StatsDetails statsDetails
#JsonProperty("stats")
private List<StatsDetails> statsDetailsList
so i can have either statsDetails or statsDetailsList only one of these being included while forming a json.
I also have a separate JsonMapper code that transforms this pojo data into a json which i haven't included here.

You cannot do that. It will throw JsonMappingException jackson cannot know which of the fields are you referring to. You can try it by yourself with the following code:
POJOClass:
import com.fasterxml.jackson.annotation.JsonGetter;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonSetter;
import java.util.List;
public class POJOClass {
public POJOClass(String object) {
this.object = object;
}
public POJOClass(List<String> objectList) {
this.objectList = objectList;
}
#JsonProperty("object")
public String object;
#JsonProperty("object")
public List<String> objectList;
#JsonGetter("object")
public String getObject() {
return object;
}
#JsonGetter("object")
public List<String> getObjectList() {
return objectList;
}
#JsonSetter("object")
public void setObject(String object) {
this.object = object;
}
#JsonSetter("object")
public void setObjectList(List<String> objectList) {
this.objectList = objectList;
}
}
Main class:
import com.fasterxml.jackson.databind.ObjectMapper;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;
public class MainClass {
public static void main(String[] args) {
String text = "f";
List<String> list = Arrays.asList("a", "b", "c");
ObjectMapper mapper = new ObjectMapper();
try {
String json = mapper.writeValueAsString(new POJOClass(text));
String listJson = mapper.writeValueAsString(new POJOClass(list));
System.out.println("json=" + json);
System.out.println("listJson=" + listJson);
} catch (IOException e) {
e.printStackTrace();
}
}
}
The output:
com.fasterxml.jackson.databind.JsonMappingException: Multiple fields representing property "object": POJOClass#object vs POJOClass#objectList

JCodeModel ref not imported

I'm trying to create a class (MoMoTest.class) which extends a generic abstract class (MappingObject.class). Everything looks good, except that JCodeModel doesn't import the narrowed class (MoTest.class), although I created a JClass of it with codeModel.ref:
MappingObject.class:
package test;
public abstract class MappingObject<T> {
protected T dataObject;
public MappingObject( T dataObject ) {
this.dataObject = dataObject;
}
public abstract T getDataObject();
public abstract String getStandardFormat();
}
MoTest.class:
package test;
public class MoTest {
}
MappingObjectCreator.class:
package test;
import com.sun.codemodel.*;
import java.io.File;
import java.io.IOException;
public class MappingObjectCreator {
public JDefinedClass getMappingObject(JCodeModel codeModel, JPackage jPackage, Class<?> clazz) throws JClassAlreadyExistsException {
JClass ref = codeModel.ref(clazz); // Not imported in MoMoTest.class
JDefinedClass definedClass = jPackage._class("Mo" + ref.name());
JClass superClass = codeModel.ref(MappingObject.class).narrow(ref);
definedClass._extends(superClass);
JFieldRef dataObject = JExpr.ref("dataObject");
JMethod constructor = definedClass.constructor(JMod.PUBLIC);
JVar param = constructor.param(ref, ref.name());
constructor.body().invoke("super").arg(param);
JMethod getDataObject = definedClass.method(JMod.PUBLIC, ref, "getDataObject");
getDataObject.annotate(codeModel.ref(Override.class));
getDataObject.body()._return(dataObject);
JMethod getStandardFormat = definedClass.method(JMod.PUBLIC, String.class, "getStandardFormat");
getStandardFormat.annotate(codeModel.ref(Override.class));
getStandardFormat.body()._return(dataObject.invoke("toString"));
return definedClass;
}
public void getMappingObject(Class clazz, String path) throws JClassAlreadyExistsException, IOException {
JCodeModel codeModel = new JCodeModel();
JPackage jPackage = codeModel._package(clazz.getPackage().getName());
getMappingObject(codeModel, jPackage, clazz);
codeModel.build(new File(path));
}
public static void main(String[] args) throws IOException, JClassAlreadyExistsException {
new MappingObjectCreator().getMappingObject(MoTest.class, "src/main/java");
}
}
Result (MoMoTest.class):
package test;
public class MoMoTest
extends MappingObject<test.MoTest>
{
public MoMoTest(test.MoTest MoTest) {
super(MoTest);
}
#Override
public test.MoTest getDataObject() {
return dataObject;
}
#Override
public String getStandardFormat() {
return dataObject.toString();
}
}
So why is Motest.class not imported in MomoTest.class ?

After modifying the parametername of the constructor of the generated class (MoMoTest.class) to first-letter-lower-case it somehow works:
MappingObjectCreator.class:
JMethod constructor = definedClass.constructor(JMod.PUBLIC);
char[] refName = ref.name().toCharArray();
refName[0] = Character.toLowerCase(refName[0]);
JVar param = constructor.param(ref, new String(refName));
constructor.body().invoke("super").arg(param);
Result:
package test;
public class MoMoTest
extends MappingObject<MoTest>
{
public MoMoTest(MoTest moTest) {
super(moTest);
}
#Override
public MoTest getDataObject() {
return dataObject;
}
#Override
public String getStandardFormat() {
return dataObject.toString();
}
}

Prevent Jackson XML mapper from adding wstxns to namespaces

When serialising objects to XML and specifying namespaces for properties using
#JacksonXmlRootElement(namespace = "http://...")
Jackson will append or prepend ´wstxns1´ to the namespace. For example, say we have these classes:
VtexSkuAttributeValues.java
#JacksonXmlRootElement(localName = "listStockKeepingUnitName")
public class VtexSkuAttributeValues {
#JacksonXmlProperty(localName = "StockKeepingUnitFieldNameDTO", namespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts")
#JacksonXmlElementWrapper(useWrapping = false)
private VtexSkuAttributeValue[] stockKeepingUnitFieldNameDTO;
public VtexSkuAttributeValue[] getStockKeepingUnitFieldNameDTO() {
return stockKeepingUnitFieldNameDTO;
}
public void setValues(VtexSkuAttributeValue[] values) {
this.stockKeepingUnitFieldNameDTO = values;
}
}
VtexSkuAttributeValue.java
#JacksonXmlRootElement(localName = "StockKeepingUnitFieldNameDTO", namespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts")
public class VtexSkuAttributeValue {
private String fieldName;
private FieldValues fieldValues;
private int idSku;
public int getIdSku() {
return idSku;
}
public String getFieldName() {
return fieldName;
}
public FieldValues getFieldValues() {
return fieldValues;
}
public void setIdSku(int idSku) {
this.idSku = idSku;
}
public void setFieldName(String fieldName) {
this.fieldName = fieldName;
}
public void setFieldValues(FieldValues fieldValues) {
this.fieldValues = fieldValues;
}
#JacksonXmlRootElement(localName = "fieldValues", namespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts")
public static class FieldValues {
#JacksonXmlProperty(namespace = "http://schemas.microsoft.com/2003/10/Serialization/Arrays")
#JacksonXmlElementWrapper(useWrapping = false)
public String[] string;
public String[] getString() {
return string;
}
public void setValues(String[] values) {
this.string = values;
}
}
}
I then use the XmlMapper to serialise and get:
<listStockKeepingUnitName>
<wstxns1:StockKeepingUnitFieldNameDTO xmlns:wstxns1="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
<fieldName>talle</fieldName>
<fieldValues>
<wstxns2:string xmlns:wstxns2="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6184</wstxns2:string>
</fieldValues>
<idSku>258645</idSku>
</wstxns1:StockKeepingUnitFieldNameDTO>
<wstxns3:StockKeepingUnitFieldNameDTO xmlns:wstxns3="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
<fieldName>color</fieldName>
<fieldValues>
<wstxns4:string xmlns:wstxns4="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6244</wstxns4:string>
</fieldValues>
<idSku>258645</idSku>
</wstxns3:StockKeepingUnitFieldNameDTO>
</listStockKeepingUnitName>
Even though this is valid XML, the web service I'm working with doesn't accept it. I debugged it and it's due to the wstxns properties in the tags that Jackson adds for some reason.
Is there a way to prevent Jackson from adding that to the tags. The only workaround I could come up with is performing a string.replaceAll on the resulting XML but it's obviously not ideal.

To write XML Jackson uses javax.xml.stream.XMLStreamWriter. You can configure instance of that class and define your own prefixes for namespaces and set default one if needed. To do that we need to extend com.fasterxml.jackson.dataformat.xml.XmlFactory class and override a method which creates XMLStreamWriter instance. Example implementation could look like below:
class NamespaceXmlFactory extends XmlFactory {
private final String defaultNamespace;
private final Map<String, String> prefix2Namespace;
public NamespaceXmlFactory(String defaultNamespace, Map<String, String> prefix2Namespace) {
this.defaultNamespace = Objects.requireNonNull(defaultNamespace);
this.prefix2Namespace = Objects.requireNonNull(prefix2Namespace);
}
#Override
protected XMLStreamWriter _createXmlWriter(IOContext ctxt, Writer w) throws IOException {
XMLStreamWriter writer = super._createXmlWriter(ctxt, w);
try {
writer.setDefaultNamespace(defaultNamespace);
for (Map.Entry<String, String> e : prefix2Namespace.entrySet()) {
writer.setPrefix(e.getKey(), e.getValue());
}
} catch (XMLStreamException e) {
StaxUtil.throwAsGenerationException(e, null);
}
return writer;
}
}
You can use it as below:
import com.fasterxml.jackson.core.io.IOContext;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.dataformat.xml.XmlFactory;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
import com.fasterxml.jackson.dataformat.xml.util.StaxUtil;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamWriter;
import java.io.IOException;
import java.io.Writer;
import java.util.Collections;
import java.util.Map;
import java.util.Objects;
public class XmlMapperApp {
public static void main(String[] args) throws Exception {
String defaultNamespace = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts";
Map<String, String> otherNamespaces = Collections.singletonMap("a", "http://schemas.microsoft.com/2003/10/Serialization/Arrays");
XmlMapper xmlMapper = new XmlMapper(new NamespaceXmlFactory(defaultNamespace, otherNamespaces));
xmlMapper.enable(SerializationFeature.INDENT_OUTPUT);
System.out.println(xmlMapper.writeValueAsString(new VtexSkuAttributeValues()));
}
}
In VtexSkuAttributeValues class you can declare:
public static final String DEF_NMS = "http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts";
and use it for every class and field where it should be used as default namespace. For example:
#JacksonXmlProperty(localName = "StockKeepingUnitFieldNameDTO", namespace = DEF_NMS)
For properties, for which you do not want to change name you can use:
#JacksonXmlProperty(namespace = VtexSkuAttributeValues.DEF_NMS)
Above code prints for some random data:
<listStockKeepingUnitName>
<StockKeepingUnitFieldNameDTO xmlns="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
<fieldName>Name1</fieldName>
<fieldValues>
<a:string xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6184</a:string>
</fieldValues>
<idSku>123</idSku>
</StockKeepingUnitFieldNameDTO>
<StockKeepingUnitFieldNameDTO xmlns="http://schemas.datacontract.org/2004/07/Vtex.Commerce.WebApps.AdminWcfService.Contracts">
<fieldName>Name1</fieldName>
<fieldValues>
<a:string xmlns:a="http://schemas.microsoft.com/2003/10/Serialization/Arrays">6184</a:string>
</fieldValues>
<idSku>123</idSku>
</StockKeepingUnitFieldNameDTO>
</listStockKeepingUnitName>
If it is not what you want you can play with that code and try other methods which are available for you to configure this instance.
To create this example Jackson in version 2.9.9 was used.

This seems to be the missing piece. It allows you to set the prefix and namespace.
static class NamespaceXmlFactory extends XmlFactory {
private final String defaultNamespace;
private final Map<String, String> prefix2Namespace;
public NamespaceXmlFactory(String defaultNamespace, Map<String, String> prefix2Namespace) {
this.defaultNamespace = Objects.requireNonNull(defaultNamespace);
this.prefix2Namespace = Objects.requireNonNull(prefix2Namespace);
}
#Override
protected XMLStreamWriter _createXmlWriter(IOContext ctxt, Writer w) throws IOException {
XMLStreamWriter2 writer = (XMLStreamWriter2)super._createXmlWriter(ctxt, w);
try {
writer.setDefaultNamespace(defaultNamespace);
writer.setPrefix("xsi", "http://www.w3.org/2001/XMLSchema-instance");
for (Map.Entry<String, String> e : prefix2Namespace.entrySet()) {
writer.setPrefix(e.getKey(), e.getValue());
}
} catch (XMLStreamException e) {
StaxUtil.throwAsGenerationException(e, null);
}
return writer;
}
}
The only remaining issue I have is
#JacksonXmlProperty(localName = "#xsi.type", isAttribute = true, namespace = "http://www.w3.org/2001/XMLSchema-instance")
#JsonProperty("#xsi.type")
private String type;
Creates the following output:
Still trying to resolve how to make it be xsi:type="networkObjectGroupDTO" instead.

JAXB element name based on object property

I have to create object model for following XMLs:
XML sample 1:
<InvoiceAdd>
<TxnDate>2009-01-21</TxnDate>
<RefNumber>1</RefNumber>
<InvoiceLineAdd>
</InvoiceLineAdd>
</InvoiceAdd>
XML Sample 2:
<SalesOrderAdd>
<TxnDate>2009-01-21</TxnDate>
<RefNumber>1</RefNumber>
<SalesOrderLineAdd>
</SalesOrderLineAdd>
</SalesOrderAdd>
The XML output will be based on a single string parameter or enum. String txnType = "Invoice"; (or "SalesOrder");
I would use single class TransactionAdd:
#XmlRootElement
public class TransactionAdd {
public String txnDate;
public String refNumber;
private String txnType;
...
public List<LineAdd> lines;
}
instead of using subclasses or anything else. The code which creates the TransactionAdd instance is the same for both types of transaction it only differs on the type.
This XML is used by a rather known product called QuickBooks and is consumed by QuickBooks web service - so I can't change the XML, but I want to make it easy to be able to set element name based on property (txnType).
I would consider something like a method to determine target element name:
#XmlRootElement
public class TransactionAdd {
public String txnDate;
public String refNumber;
private String txnType;
...
public List<LineAdd> lines;
public String getElementName() {
return txnType + "Add";
}
}
Different transactions will be created using following code:
t = new TransactionAdd();
t.txnDate = "2010-12-15";
t.refNumber = "123";
t.txnType = "Invoice";
The goal is to serialize t object with the top-level element name based on txnType. E.g.:
<InvoiceAdd>
<TxnDate>2009-01-21</TxnDate>
<RefNumber>1</RefNumber>
</InvoiceAdd>
In case of t.txnType = "SalesOrder" the result should be
<SalesOrderAdd>
<TxnDate>2009-01-21</TxnDate>
<RefNumber>1</RefNumber>
</SalesOrderAdd>
At the moment I see only one workaround with subclasses InvoiceAdd and SalesOrderAdd and using #XmlElementRef annotation to have a name based on class name. But it will need to instantiate different classes based on transaction type and also will need to have two other different classes InvoiceLineAdd and SalesOrderLineAdd which looks rather ugly.
Please suggest me any solution to handle this. I would consider something simple.

To address the root element aspect you could do will need to leverage #XmlRegistry and #XmlElementDecl. This will give us multiple possible root elements for the TransactionAdd class:
import javax.xml.bind.JAXBElement;
import javax.xml.bind.annotation.XmlElementDecl;
import javax.xml.bind.annotation.XmlRegistry;
import javax.xml.namespace.QName;
#XmlRegistry
public class ObjectFactory {
#XmlElementDecl(name="InvoiceAdd")
JAXBElement<TransactionAdd> createInvoiceAdd(TransactionAdd invoiceAdd) {
return new JAXBElement<TransactionAdd>(new QName("InvoiceAdd"), TransactionAdd.class, invoiceAdd);
}
#XmlElementDecl(name="SalesOrderAdd")
JAXBElement<TransactionAdd> createSalesOrderAdd(TransactionAdd salesOrderAdd) {
return new JAXBElement<TransactionAdd>(new QName("SalesOrderAdd"), TransactionAdd.class, salesOrderAdd);
}
}
Your TransactionAdd class will look something like the following. The interesting thing to note is that we will make the txnType property #XmlTransient.
import java.util.List;
import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlTransient;
public class TransactionAdd {
private String txnDate;
private String refNumber;
private String txnType;
private List<LineAdd> lines;
#XmlElement(name="TxnDate")
public String getTxnDate() {
return txnDate;
}
public void setTxnDate(String txnDate) {
this.txnDate = txnDate;
}
#XmlElement(name="RefNumber")
public String getRefNumber() {
return refNumber;
}
public void setRefNumber(String refNumber) {
this.refNumber = refNumber;
}
#XmlTransient
public String getTxnType() {
return txnType;
}
public void setTxnType(String txnType) {
this.txnType = txnType;
}
public List<LineAdd> getLines() {
return lines;
}
public void setLines(List<LineAdd> lines) {
this.lines = lines;
}
}
Then we need to supply a little logic outside the JAXB operation. For an unmarshal we will use the local part of the root element name to populate the txnType property. For a marshal we will use the value of the txnType property to create the appropriate JAXBElement.
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBElement;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(TransactionAdd.class, ObjectFactory.class);
File xml = new File("src/forum107/input1.xml");
Unmarshaller unmarshaller = jc.createUnmarshaller();
JAXBElement<TransactionAdd> je = (JAXBElement<TransactionAdd>) unmarshaller.unmarshal(xml);
TransactionAdd ta = je.getValue();
ta.setTxnType(je.getName().getLocalPart());
JAXBElement<TransactionAdd> jeOut;
if("InvoiceAdd".equals(ta.getTxnType())) {
jeOut = new ObjectFactory().createInvoiceAdd(ta);
} else {
jeOut = new ObjectFactory().createSalesOrderAdd(ta);
}
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(jeOut, System.out);
}
}
To Do
I will look into addressing the lines property next.

You could use an XmlAdapter for this. Based on the String value of the txnType property you would have the XmlAdapter marshal an instance of an Object corresponding to InvoiceLineAdd or SalesOrderLineAdd.
This is how it would look:
TransactionAdd
On the txnType property we will use a combination of #XmlJavaTypeAdapter and #XmlElementRef:
import javax.xml.bind.annotation.XmlElementRef;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
#XmlRootElement
public class TransactionAdd {
private String txnType;
#XmlJavaTypeAdapter(MyAdapter.class)
#XmlElementRef
public String getTxnType() {
return txnType;
}
public void setTxnType(String txnType) {
this.txnType = txnType;
}
}
The adapted objects will look like:
AbstractAdd
import javax.xml.bind.annotation.XmlSeeAlso;
#XmlSeeAlso({InvoiceAdd.class, SalesOrderAdd.class})
public class AbstractAdd {
}
InvoiceAdd
import javax.xml.bind.annotation.XmlRootElement;
#XmlRootElement
public class InvoiceAdd extends AbstractAdd {
}
SalesOrderAdd
import javax.xml.bind.annotation.XmlRootElement;
#XmlRootElement
public class SalesOrderAdd extends AbstractAdd {
}
The XmlAdapter to convert between the String and the adapted objects will look like:
import javax.xml.bind.annotation.adapters.XmlAdapter;
public class MyAdapter extends XmlAdapter<AbstractAdd, String> {
#Override
public String unmarshal(AbstractAdd v) throws Exception {
if(v instanceof SalesOrderAdd) {
return "salesOrderAdd";
}
return "invoiceAdd";
}
#Override
public AbstractAdd marshal(String v) throws Exception {
if("salesOrderAdd".equals(v)) {
return new SalesOrderAdd();
}
return new InvoiceAdd();
}
}
The following demo code can be used:
import java.io.File;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(TransactionAdd.class);
File xml = new File("input.xml");
Unmarshaller unmarshaller = jc.createUnmarshaller();
TransactionAdd ta = (TransactionAdd) unmarshaller.unmarshal(xml);
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(ta, System.out);
}
}
To produce/consume the following XML:
<transactionAdd>
<salesOrderAdd/>
</transactionAdd>
For more information see:
http://bdoughan.blogspot.com/2010/07/xmladapter-jaxbs-secret-weapon.html

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