Using optional fields with StaxEventItemReader - spring-batch

Question

I have a Spring Batch application and I'm using the StaxEventItemReader as my ItemReader. By default XStream requires us to declare a property for each possible XML tag or else it throws an UnknownFieldException exception. There are ways to code around this with Java but with Spring Batch, the InputReader doesn't seem to have a way to modify it. Is there a way to flag fields as optional in the xml?
My bean is configured basically like this
<job id="synchronizecustomerData" xmlns="http://www.springframework.org/schema/batch">
<step id="readWritecustomers">
<tasklet>
<chunk reader="customerReader"
processor="customerProcessor"
writer="customerSyncWriter"
commit-interval="1"
skip-policy="alwaysSkip" >
</chunk>
</tasklet>
</step>
</job>
<bean id="customerReader" class="org.springframework.batch.item.xml.StaxEventItemReader">
<property name="fragmentRootElementName" value="customer" />
<property name="resource" ref="inputResource" />
<property name="unmarshaller" ref="customerMarshaller" />
</bean>
<bean id="inputResource" class="org.springframework.core.io.FileSystemResource">
<constructor-arg value="c:/sf/data.xml" />
</bean>
<bean id="customerMarshaller" class="org.springframework.oxm.xstream.XStreamMarshaller">
<property name="aliases">
<util:map id="aliases">
<entry key="customer" value="com.company.batchmaster.sf.beans.customer" />
<entry key="name" value="java.lang.String" />
</util:map>
</property>
</bean>
<bean id="customerProcessor" class="org.springframework.batch.item.support.CompositeItemProcessor">
<property name="delegates">
<list>
<ref bean="customerTransformer" />
</list>
</property>
</bean>
<bean id="customerTransformer" class="com.company.batchmaster.sf.chunk.customerTransformer" />
<bean id="customerSyncWriter" class="com.company.batchmaster.sf.chunk.customerSyncWriter" />
My import file looks like this, just getting it up and running
<?xml version="1.0" encoding="UTF-8"?>
<records>
<customer xmlns="http://springframework.org/batch/sample/io/oxm/domain">
<name>ABC Dealer</name>
<types>CR</types>
</customer>
</records>
Thanks for any help.

Answer 1

I am assuming Customer class has properties name and type.
Annotate it as XmlAttribute.defaultValue() as described in Jaxb guide
No need to this (<entry key="name" value="java.lang.String" />) alias because you are unmarshalling a complete Customer object from a node as specified with <property name="fragmentRootElementName" value="customer" />