JAXB marshalling for BigDecimal using fractionDigits

Question

So here's my problem. I'm given an XSD to which my generated XML file should comply. Using the org.apache.cxf.cxf-xjc-plugin maven plugin and an external binding file I generate the source code. But when I'm trying marshall my object the generated XML doesn't meet my requirements.

My XSD contains the following:

<xsd:element maxOccurs="1" minOccurs="0" name="amount">
  <xsd:simpleType>
    <xsd:restriction base="xsd:decimal">
      <xsd:totalDigits value="13" />
      <xsd:fractionDigits value="2" />
    </xsd:restriction>
  </xsd:simpleType>
</xsd:element>
...
<xsd:element maxOccurs="1" minOccurs="0" name="rate">
  <xsd:simpleType>
    <xsd:restriction base="xsd:decimal">
      <xsd:totalDigits value="8" />
      <xsd:fractionDigits value="5" />
    </xsd:restriction>
  </xsd:simpleType>
</xsd:element>

And the generated piece of XML looks like this:

<amount>109.5</amount>
...
<rate>10.25</rate>

While I was expecting it to be:

<amount>109.50</amount>
...
<rate>10.25000</rate>

Is there a way to solve this problem in a clean way?

I would prefer not writing several adapters for every single totalDigits, fractionDigits combination. And as the XSD is subject to change I'd like to leave the generated source code untouched.

Answer 1

You will need to use XmlAdapter for this use case. Below is a sample binding file that will help you generate them. The logic would be contained in a DecimalFormatter class that contained methods for all the different required formats.

<jxb:bindings xmlns:xs="http://www.w3.org/2001/XMLSchema"
    xmlns:jxb="http://java.sun.com/xml/ns/jaxb" version="2.1">
    <jxb:bindings schemaLocation="schema.xsd">
        <jxb:bindings node="//xs:element[@name='amount']">
            <jxb:property>
                <jxb:baseType>
                    <jxb:javaType name="java.math.BigDecimal"
                        parseMethod="org.example.DecimalFormatter.parseDecimal"
                        printMethod="org.example.DecimalFormatter.printDecimal_2Places" />
                </jxb:baseType>
            </jxb:property>
        </jxb:bindings>
        <jxb:bindings node="//xs:element[@name='rate']">
            <jxb:property>
                <jxb:baseType>
                    <jxb:javaType name="java.math.BigDecimal"
                        parseMethod="org.example.DecimalFormatter.parseDecimal"
                        printMethod="org.example.DecimalFormatter.printDecimal_5Places" />
                </jxb:baseType>
            </jxb:property>
        </jxb:bindings>
    </jxb:bindings>
</jxb:bindings>

For More Information

• http://blog.bdoughan.com/2011/08/xml-schema-to-java-generating.html