CODEWITHSUNDEEP
javajaxbeclipselink
Chris A
Chris A

Reputation: 1100

How to exclude "xs:type" tag when extending a transient

Desired outcome:

Easily switch between

<root>
  <child>
    <prop1>..</prop1>
    <prop2>..</prop2>
  </child>
<root>

and

<root>
  <child>
    <prop1>..</prop1>
    <prop2>..</prop2>
    <prop3>..</prop3>
    <prop4>..</prop4>
  </child>
</root>

My code

Root.java
@XmlRootElement(name= "root")
public class Root {
  @XmlElement(name="child")
  public Child child
}
ExtendedRoot.java
@XmlRootElement(name= "root")
public class ExtendedRoot extends Root {
  @XmlElement(name="child")
  public ExtendedChild child
}
Child.java
@XmlTransient
public class Child {
  // prop1, prop2
}
ExtendedChild.java
@XmlType(propOrder = {"prop1", "prop3","prop4", "prop2"})
public class ExtendedChild extends Child {
  // prop3, prop4
}

Main

System.setProperty("javax.xml.bind.context.factory", "org.eclipse.persistence.jaxb.JAXBContextFactory")
Class clazz = extendChild ? ExtendedRoot.class : Root.class;
JAXBContext jc = JAXBContext.newInstance(clazz);
Marshaller marshaller = jc.createMarshaller();
marshaller.marshal(formattedJob, tempFile);

Actual outcome

<root>
  <child xs:type="ExtendedChild">
    <prop1>..</prop1>
    <prop2>..</prop2>
    <prop3>..</prop3>
    <prop4>..</prop4>
  </child>
</root>

How can I exclude this xs:type=... from the child tag?

Upvotes: 1

Views: 29

Answers (1)

Karsten
Karsten

Reputation: 420

The xs:type is used here because the value of the child property is polymorphic. Without it JAXB doesn't have a chance to decide which class to use when reading your own XML documents. JAXB isn't that clever to first introspect the element and then select the best fitting class.

But there are some other points while reading XML:

Are you aware, that ExtendedRoot has two properties named child (the one inherited from Root, super.child and its own, this.child)? Since ExtendedChild is a Child also an ExtendedChild may be stored to either of the two properties:

  1. First you may wonder where your child elements turn up in your objects.
  2. Because you can store an ExtendedChild to Root.child there is no necessity for ExtendedRoot.child. Without this there is even no necessity for ExtendedRoot in this example.

If you insist on keeping ExtendedRoot be aware that JAXB can't decide wether to use Root or ExtendedRoot if it stumbles about a root element.

Upvotes: 1

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