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Unmarshalling multiple XML elements to one field using JAXB

I have an XML file in format described below. I'm currently using JAXB to unmarshall the XML elements (event) to Java objects (Event). All properties work fine, except one...
As you can see in the XML, the date element stores only the date and the time stores only the time of the event. I would like to combine these two XML elements into one LocalDataTime field named time, with appropriate getters and setters.
XML:
...
<event>
...
<date>2014-02-19</date>
<time>2000-01-01T14:17:00Z</time>
...
</event>
...
Desired Java Object:
public class Event {
...
// Returns a combination of the date and time stored in the XML
public LocalDateTime getDateTime() {
return dateTime;
}
...
}
My first thought was to use a XMLAdapter but it seems that this only allows me to map 1 XML element to 1 Java object.
After that I tried to implement this by overriding the setters setTime and setDate. These setters would each just change the time or date of the stored time.. But I wasn't able to get it working and it also seemed a quite ugly way to do this.
I already read the following JAXB convert multiple attributes to one type while unmarshalling. But for this project, I would rather not use an external library like MOXy.
Does anyone know how to do this using solely JAXB in a clean way?

You could define in your Event object lifecycle methods:
void afterUnmarshal(Unmarshaller unm, Object parent) {
localDateTime = ....
};
boolean beforeMarshal(Marshaller mar) {
date = localDateTime.toDate();
....
};
to construct the LocalDateTime property after unmarshalling (using the date and time values), and prepare date/time fields before marshalling using the current LocaLDateTime value.
You would still need the time/date fields to match the xml and the localDateTime field must be XmlTransient. So it is not so different from the set/getter approach but probably more "clean".

Marshal an object as one of its properties with Jackson (as for value objects i.e primitive types wrappers)

EDIT: Previous answer does not work (it stills create a nested object)
I'm using Jersey and Jackson.
I got a class like
#XmlAccessorType(XmlAccessType.NONE)
public class Name {
private String value;
#XmlValue
public String getValue(){...}
public void setValue(String value){...}
}
used as in
public class Person{
#XmlElement(name = "IDName")
public Name getName(){...}
}
I'd like to marshal Name object as the value of it's identity property.
How can I achieve that?
<Person>
<IDName>foo</IDName>
</Person>
instead of
<Person>
<IDName>
<Value>foo</Value>
</IDName>
</Person>
I'd tried both to indicate in Person that Name object should be marshalled as itself.getValue() and either to indicate within Name class to marshal without any element wrapper (its fields directly) with no luck.

A possible solution is replacing #XmlValue annotation with Jackson's #JsonValue to make it work (tested).
I infer from http://wiki.fasterxml.com/JacksonJAXBAnnotations that it can be the only solution for now
According to this the official documentation
#javax.xml.bind.annotation.XmlValue
The field/property to which this annotation is applied will be named "value".
So maybe it's limited by design. Any better answer, specially if using JAXB annotations alone, will be much appreciated

Unmarshalling a date from an XML String to entity using JAXB

When I use JAXB, there is something wrong.
I convert entity to a xml String and everything is ok.
But when I convert xml String back to entity, some information is lost (All of them have the same type java.util.Date).
In entity:
public Date flightBaseDate;
In xml:
<flightBaseDate>2013-09-16T00:00:00 08:00</flightBaseDate>
after unmarshalling, getFlightBaseDate() returns null.
I googled.
Following one suggestion, I used # in my entity.
Then it is:
#XmlElement(name = "timestamp", required = true)
public Date flightBaseDate;
I'm sure it will be perfect,
but...throws Exception, like this:
com.sun.xml.internal.bind.v2.runtime.IllegalAnnotationsException: 1 counts of IllegalAnnotationExceptions
Class has two properties of the same name "flightBaseDate"
this problem is related to the following location:
at public java.lang.String com.wonders.nlia.omms.vo.FlightServiceInfoVo.getFlightBaseDate()
at com.wonders.nlia.omms.vo.FlightServiceInfoVo
this problem is related to the following location:
at public java.lang.String com.wonders.nlia.omms.vo.FlightServiceInfoVo.flightBaseDate
at com.wonders.nlia.omms.vo.FlightServiceInfoVo
Why JAXB could not distinguish between the property and its getMethod?
How to solve it?
Platform：jdk7 win7 eclipse tomcat wtp
My Unmarshalling code is:
JAXBContext context = JAXBContext.newInstance(FlightServiceInfoVo.class);
Unmarshaller unMarshaller = context.createUnmarshaller();
FlightServiceInfoVo flightServiceInfoVo =(FlightServiceInfoVo)unMarshaller.unmarshal(new StringReader(flightServiceInfoVoXml));
flightServiceInfoVoXml is a String.

You can configure JAXB in many different ways. You have chosen Annotations to define the binding (this is allright, do not worry).
I strongle recommend you read about that technique first as there are a lot of pitfalls. Here is a link to a good tutorial. Here is the part in the tutorial which explains why your binding does not work: XmlAccessorType part
As for your specific issue:
In general you have to tell JAXB what and how to bind the java object to it's XML representation. If you do not do anything, then by default all public members of your class are bound (as you can read here).
Additionally you have chosen to annotate the getter method of your public member, which then just pushes the same variable twice to your XML which later causes the exception you see.
To fix your error, either specify a different mapping strategy for your class by putting e.g. (#XmlAccessorType(XmlAccessType.NONE)) before your class declaration or move the annotation from the getter method to the property.
By the way: Having a getter method and a public member variable does not make sense at all. So making your member variable private will also fix your issue with JAXB and be a lot better for your class design.

the exception clearly says that the property name is duplicated, so check you class for a property 'flightBaseDae', it should be unique. remove the duplicate then unmarshall it

Changing class without changing a schema

I have a xsd schema which I'm not allowed to change. It produce generated java classes.
Assume that classes looks as follows:
class Data {
protected List<Value> value;
...
}
class Value {
...
}
Now I need to have my own MyValue ideally to be extended from Value.
class MyValue extends Value {
Integer myOwnField1;
Long anotherProperty;
}
And be able to say unmarshaller to use MyValue instead of Value when it parses xml file.
Later I would be able to use the fact that MyValue can contain some useful new fields inside, make operations over them, change them, etc. So I want extend the functionality which I have in schema without changing it.
Is that somehow possible to replace Value by MyValue for unmarshaller?
Apart from the obvious way to create a Map where I can map object which was generated by unmarshaller with my own fields and properties in MyValue. I'd like to avoid this way.

Can you load the list using bean properties?
public void setValue(List<Value> value) {
this.value = ...convert to List<MyValue>...
}

You might be interested in unmarshalling by declared type: indeed, if you override your XSD from the root element to every child element you need to override, you could use a second argument in unmarshal method to sepecify your custom mapping.
<T> JAXBElement<T> unmarshal(Source source,
Class<T> declaredType)
throws JAXBException
[...] declaredType - appropriate JAXB mapped class to hold
source's xml root element
(see Unmarshaller javadoc for more detailed info)

Handling different object types contained within the same set of elements

I have an XML document that looks something like the following:
Note that I cannot change the schema because it is part of a standard XML Schema (Library of Congress METS).
<amdSec ID="AMDSEC001">
<digiprovMD ID="DMD001">
<mdWrap MDTYPE="OBJECT">
<xmlData>
<object xsi:type="file">
.....
</object>
</xmlData>
</mdWrap>
</digiprovMD>
<digiprovMD ID="DMD001_EVENT">
<mdWrap MDTYPE="EVENT">
<xmlData>
<event xsi:type="event">
.....
</event>
</xmlData>
</mdWrap>
</digiprovMD>
</amdSec>
As you can see, the inner element <mdWrap> can contain elements of different types; in this case they're <event> and <object>, but it isn't constrained to just those two types. Creating two classes (like below), marshals okay, but this doesn't work for unmarshalling.
class ObjectMDWrap {
#XmlElementWrapper(name = "xmlData")
#XmlElement(name = "object")
List<MyObject> object; //Wrapped in list to use #XmlElementWrapper
}
class EventMDWrap {
#XmlElementWrapper(name = "xmlData")
#XmlElement(name = "event")
List<MyEvent> event; //Wrapped in list to use #XmlElementWrapper
}
What can I do so that JAXB unmarshals the correct "type" of MDWrap?

I think, the best solution in this case is a generating POJO classes using XJC tool.
Download XSD file which describe XML file.
Using XJC tool convert XSD file into POJO classes. If XSD is not correct - fix it.
Make some changes if you need in generated classes.
Use this classes in marshalling / unmarshalling process.

I was able to figure out the solution, and it's much simpler than I initially thought (which speaks to my relative inexperience with XML and JAXB). By creating my MDWrap class in the following way
class MDWrap {
#XmlAnyElement(lax = true)
#XmlElementWrapper(name = "xmlData")
Object wrappedMD;
}
Then MDWrap can contain an object of any type, and will unmarshal properly, as long as the class of which wrappedMD is an instance of is annotated with #XmlRootElement. The trick is to annotate wrappedMD as XmlAnyElement.