Custom Bean Factories

You can configure Dozer to use custom bean factories to create new instances of destination data objects during the mapping process. By default Dozer just creates a new instance of any destination objects using a default constructor. This is sufficient for most use cases, but if you need more flexibility you can specify your own bean factories to instantiate the data objects.

Your custom bean factory must implement the com.github.dozermapper.core.BeanFactory interface. By default the Dozer mapping engine will use the destination object class name for the bean id when calling the factory.

public interface BeanFactory {
  public Object createBean(Object source, Class sourceClass,
      String targetBeanId, BeanContainer beanContainer);
}

Next, in your Dozer mapping file(s) you just need to specify a bean-factory xml attribute for any mappings that you want to use a custom factory.

In the following example, the SampleCustomBeanFactory will be used to create any new instances of the InsideTestObjectPrime java bean data object.

<mapping>
    <class-a>com.example.vo.InsideTestObject</class-a>
    <class-b bean-factory="com.example.factories.SomeCustomBeanFactory">
        com.example.vo.InsideTestObjectPrime
    </class-b>
</mapping>

If your factory looks up beans based on a different id than class name, you can specify a factory-bean-id xml attribute. At runtime the specified factory-bean-id will be passed to the factory instead of class name.

<mapping>
    <class-a>com.example.vo.InsideTestObject</class-a>
    <class-b bean-factory="com.example.factories.SomeCustomBeanFactory" factory-bean-id="someBeanLookupId">
        com.example.vo.InsideTestObjectPrime
    </class-b>
</mapping>

Specifying Default Factories

Alternatively, bean factories can be specified in the default configuration section of any Dozer mapping file(s). The default factory would be used for any mappings in that file.

<configuration>
    <stop-on-errors>true</stop-on-errors>
    <wildcard>true</wildcard>
    <bean-factory>com.example.factories.SomeDefaultBeanFactory
  </bean-factory>
</configuration>

Bean factories can also be specified at the mapping level. The specified factory would be used for class-a and class-b.

<mapping bean-factory="com.example.factories.SomeCustomBeanFactory">
    <class-a>com.example.vo.TestObject</class-a>
    <class-b>com.example.vo.TestObjectPrime</class-b>
</mapping>

Spring bean factory injection

Bean factories can be injected via Spring or similar inversion of control techniques.

<beans>
    <bean id="com.github.dozermapper.core.Mapper" class="com.github.dozermapper.core.DozerBeanMapper">
        <property name="mappingFiles">
            <list>
                <value>dozerBeanMapping.xml</value>
            </list>
        </property>
        <property name="factories">
            <map>
                <!-- the key matches the name of the factory in the
             dozerBeanMapping.xml file -->
                <entry key="com.github.dozermapper.core.factories.SampleCustomBeanFactory">
                    <ref bean="sampleCustomBeanFactory" />
                </entry>
                <!-- more factories can be supplied with additional
             entry's -->
            </map>
        </property>
    </bean>
    <bean id="sampleCustomBeanFactory" class="com.github.dozermapper.core.factories.SampleCustomBeanFactory" />
</beans>

By defining your factories as Spring beans you can then inject them into the Mapper instance.

Custom Bean Factories