Thread: is this a bug in JAXB or a problem of me?

Hi

There is a problem that keeps puzzling me. I tried to google to find the reason and there is just none.
Therefore, I am not sure if somebody might know.

Say I have a schema like the following,

        <xs:element name="api">
          <xs:complexType>
            <xs:choice maxOccurs="unbounded">  <--------
              <xs:element ref="a" minOccurs="1" />
              <xs:element ref="b" minOccurs="1" />
              <xs:element ref="c" minOccurs="1" />

CASE1: When the line pointed by the arrow is like

        <xs:choice maxOccurs="unbounded">

JAXB "xjc -p SomePackageName -d . ...." would generate a variable in Api.java such as

        protected List<Object> aOrBOrC;

CASE2: However, if I change it to

        <xs:choice maxOccurs="1">

JAXB generates

        protected A a;
        protected B b;
        protected C c;

My question is in CASE1, how do I retrieve the value of A, B, and C individually since it is only given
ONE variable although its a list of them. aOrBOrC can only be either a, b or c. What if my instance of
the xml contains values for all a, b, and c.
I would expect xjc to generate something like the following for CASE1.

        protected List<A> a;
        protected List<B> b;
        protected List<C> c;

This produce

 protected List<A> a;
 protected List<B> b;
 protected List<C> c;

But as soon as

 <xs:choice maxOccurs="unbounded">
      <xs:element ref="a" maxOccurs="unbounded" />
      <xs:element ref="b" maxOccurs="unbounded" />
      <xs:element ref="c" maxOccurs="unbounded" />
 </xs:choice>

it generates

protected List<Object> aOrBOrC;

I thought the <xs:choice maxOccurs="unbounded"> means I can have as many a b and c and in different order. Therefore, one variable aOrBOrC is not enough. Pls let me know what do I miss? Tx

I think I know how to retrieve the a, b, and c individually,

It seems all the instances are stored in this one List<Object> aOrBOrC; and I simply
need to loop through the list and use the instanceof to see if it belongs to a, b, or c .