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 org.dozer.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);
}         
           
      

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 specifiy 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>  
         
      

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

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

           
<beans>
  <bean id="org.dozer.Mapper" class="org.dozer.DozerBeanMapper">
    <property name="mappingFiles">
      <list>
        <value>systempropertymapping1.xml</value>
        <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="org.dozer.factories.SampleCustomBeanFactory">
         <ref bean="sampleCustomBeanFactory"/>
       </entry>
        <!-- more factories can be supplied with additional 
             entry's -->
      </map>
    </property>    
  </bean>

  <bean id="sampleCustomBeanFactory" 
        class="org.dozer.factories.SampleCustomBeanFactory"/>
</beans>