http://jira.springframework.org/browse/SWF-570

spring-webflow/src/main/java/org/springframework/webflow/config/FlowRegistryBeanDefinitionParser.java

@@ -39,6 +39,8 @@ class FlowRegistryBeanDefinitionParser extends AbstractSingleBeanDefinitionParse
 
 	private static final String FLOW_BUILDER_SERVICES_ATTRIBUTE = "flow-builder-services";
 
+	private static final String PARENT_ATTRIBUTE = "parent";
+
 	private static final String FLOW_LOCATION_ELEMENT = "flow-location";
 
 	private static final String FLOW_BUILDER_ELEMENT = "flow-builder";
@@ -65,6 +67,8 @@ class FlowRegistryBeanDefinitionParser extends AbstractSingleBeanDefinitionParse
 
 	private static final String FLOW_BUILDER_SERVICES_PROPERTY = "flowBuilderServices";
 
+	private static final String PARENT_PROPERTY = "parent";
+
 	protected Class getBeanClass(Element element) {
 		return FlowRegistryFactoryBean.class;
 	}
@@ -78,6 +82,10 @@ class FlowRegistryBeanDefinitionParser extends AbstractSingleBeanDefinitionParse
 					FlowBuilderServicesBeanDefinitionParser.registerDefaultFlowBuilderServicesBeanDefinition(
 							parserContext).getBeanName());
 		}
+		String parent = getParentAttribute(element);
+		if (StringUtils.hasText(parent)) {
+			definitionBuilder.addPropertyReference(PARENT_PROPERTY, parent);
+		}
 		definitionBuilder.addPropertyValue(FLOW_LOCATIONS_PROPERTY, parseLocations(element));
 		definitionBuilder.addPropertyValue(FLOW_BUILDERS_PROPERTY, parseFlowBuilders(element));
 	}
@@ -133,4 +141,9 @@ class FlowRegistryBeanDefinitionParser extends AbstractSingleBeanDefinitionParse
 	private String getFlowBuilderServicesAttribute(Element element) {
 		return element.getAttribute(FLOW_BUILDER_SERVICES_ATTRIBUTE);
 	}
+
+	private String getParentAttribute(Element element) {
+		return element.getAttribute(PARENT_ATTRIBUTE);
+	}
+
 }

spring-webflow/src/main/java/org/springframework/webflow/config/FlowRegistryFactoryBean.java

@@ -39,53 +39,63 @@ import org.springframework.webflow.engine.model.registry.FlowModelRegistryImpl;
  */
 class FlowRegistryFactoryBean implements FactoryBean, InitializingBean {
 
+	private FlowLocation[] flowLocations;
+
+	private FlowBuilderInfo[] flowBuilders;
+
+	private FlowBuilderServices flowBuilderServices;
+
+	private FlowDefinitionRegistry parent;
+
 	/**
 	 * The definition registry produced by this factory bean.
 	 */
 	private FlowDefinitionRegistryImpl flowRegistry;
 
 	/**
-	 * The model registry produced by this factory bean.
+	 * The model registry used to build flow models that can be assembled into registerable Flows.
 	 */
 	private FlowModelRegistryImpl flowModelRegistry;
 
-	/**
-	 * Flow definitions defined in external files that should be registered in the registry produced by this factory
-	 * bean.
-	 */
-	private FlowLocation[] flowLocations;
-
-	/**
-	 * Java {@link FlowBuilder flow builder} classes that should be registered in the registry produced by this factory
-	 * bean.
-	 */
-	private FlowBuilderInfo[] flowBuilders;
-
-	/**
-	 * The holder for services needed to build flow definitions registered in this registry.
-	 */
-	private FlowBuilderServices flowBuilderServices;
-
 	/**
 	 * A helper for creating abstract representation of externalized flow definition resources.
 	 */
 	private FlowDefinitionResourceFactory flowResourceFactory;
 
+	/**
+	 * Flow definitions defined in external files that should be registered in the registry produced by this factory
+	 * bean.
+	 */
 	public void setFlowLocations(FlowLocation[] flowLocations) {
 		this.flowLocations = flowLocations;
 	}
 
+	/**
+	 * Java {@link FlowBuilder flow builder} classes that should be registered in the registry produced by this factory
+	 * bean.
+	 */
 	public void setFlowBuilders(FlowBuilderInfo[] flowBuilders) {
 		this.flowBuilders = flowBuilders;
 	}
 
+	/**
+	 * The holder for services needed to build flow definitions registered in this registry.
+	 */
 	public void setFlowBuilderServices(FlowBuilderServices flowBuilderServices) {
 		this.flowBuilderServices = flowBuilderServices;
 	}
 
+	/**
+	 * The parent of the registry created by this factory bean.
+	 */
+	public void setParent(FlowDefinitionRegistry parent) {
+		this.parent = parent;
+	}
+
 	public void afterPropertiesSet() throws Exception {
 		flowResourceFactory = new FlowDefinitionResourceFactory(flowBuilderServices.getApplicationContext());
 		flowRegistry = new FlowDefinitionRegistryImpl();
+		flowRegistry.setParent(parent);
 		flowModelRegistry = new FlowModelRegistryImpl();
 		registerFlowLocations();
 		registerFlowBuilders();

spring-webflow/src/main/java/org/springframework/webflow/config/spring-webflow-config-2.0.xsd

@@ -71,6 +71,16 @@ Registers a custom FlowBuilder implementation in this registry.
 								<![CDATA[
 A reference to a FlowBuilderServices implementation defining custom services needed to build the flows registered in this registry.
 Optional.  For use when one or more custom builder services are required.
+]]>
+							</xsd:documentation>
+						</xsd:annotation>
+					</xsd:attribute>
+					<xsd:attribute name="parent" type="xsd:string">
+						<xsd:annotation>
+							<xsd:documentation>
+								<![CDATA[
+A reference to this registry's parent.  Registries can be organized in a hierarchy.  If a child registry does not contain a flow,
+its parent registry will be queried.
 ]]>
 							</xsd:documentation>
 						</xsd:annotation>

spring-webflow/src/main/java/org/springframework/webflow/definition/registry/FlowDefinitionRegistry.java

@@ -34,6 +34,12 @@ public interface FlowDefinitionRegistry extends FlowDefinitionLocator {
 	 */
 	public int getFlowDefinitionCount();
 
+	/**
+	 * Returns this registry'es parent registry.
+	 * @return the parent flow definition registry, or null if no parent is set
+	 */
+	public FlowDefinitionRegistry getParent();
+
 	/**
 	 * Sets this registry's parent registry. When asked by a client to locate a flow definition this registry will query
 	 * it's parent if it cannot fulfill the lookup request itself.

spring-webflow/src/main/java/org/springframework/webflow/definition/registry/FlowDefinitionRegistryImpl.java

@@ -78,6 +78,10 @@ public class FlowDefinitionRegistryImpl implements FlowDefinitionRegistry {
 		return flowDefinitions.size();
 	}
 
+	public FlowDefinitionRegistry getParent() {
+		return parent;
+	}
+
 	public void setParent(FlowDefinitionRegistry parent) {
 		this.parent = parent;
 	}

spring-webflow/src/test/java/org/springframework/webflow/config/FlowRegistryBeanDefinitionParserTests.java

@@ -56,4 +56,9 @@ public class FlowRegistryBeanDefinitionParserTests extends TestCase {
 
 		}
 	}
+
+	public void testParent() {
+		assertNotNull(registry.getParent());
+		assertEquals("parentFlow", registry.getParent().getFlowDefinition("parentFlow").getId());
+	}
 }

spring-webflow/src/test/java/org/springframework/webflow/config/flow-registry.xml

@@ -8,7 +8,7 @@
            http://www.springframework.org/schema/webflow-config
            http://www.springframework.org/schema/webflow-config/spring-webflow-config-2.0.xsd">
 
-	<webflow:flow-registry id="flowRegistry">
+	<webflow:flow-registry id="flowRegistry" parent="parentRegistry">
 		<webflow:flow-location id="flow" path="org/springframework/webflow/config/flow.xml">
 			<webflow:flow-definition-attributes>
 				<webflow:attribute name="foo" value="bar" />
@@ -26,4 +26,8 @@
 		</webflow:flow-builder>
 	</webflow:flow-registry>
 	
+	<webflow:flow-registry id="parentRegistry">
+		<webflow:flow-location id="parentFlow" path="org/springframework/webflow/config/flow.xml" />
+	</webflow:flow-registry>
+	
 </beans>