polish

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

@@ -52,6 +52,7 @@ public class FlowDefinitionRegistryImpl implements FlowDefinitionRegistry {
 
 	public FlowDefinition getFlowDefinition(String id) throws NoSuchFlowDefinitionException,
 			FlowDefinitionConstructionException {
+		Assert.hasText(id, "An id is required to lookup a FlowDefinition");
 		try {
 			if (logger.isDebugEnabled()) {
 				logger.debug("Getting FlowDefinition with id '" + id + "'");
@@ -87,7 +88,7 @@ public class FlowDefinitionRegistryImpl implements FlowDefinitionRegistry {
 	public void registerFlowDefinition(FlowDefinitionHolder definitionHolder) {
 		Assert.notNull(definitionHolder, "The holder of the flow definition to register is required");
 		if (logger.isDebugEnabled()) {
-			logger.debug("Registering flow definition " + definitionHolder);
+			logger.debug("Registering flow definition held by " + definitionHolder);
 		}
 		flowDefinitions.put(definitionHolder.getFlowDefinitionId(), definitionHolder);
 	}

spring-webflow/src/test/java/org/springframework/webflow/definition/registry/FlowDefinitionRegistryImplTests.java

@@ -47,6 +47,24 @@ public class FlowDefinitionRegistryImplTests extends TestCase {
 		}
 	}
 
+	public void testNullFlowDefinitionId() {
+		try {
+			registry.getFlowDefinition(null);
+			fail("Should have bombed with illegal argument");
+		} catch (IllegalArgumentException e) {
+
+		}
+	}
+
+	public void testBlankFlowDefinitionId() {
+		try {
+			registry.getFlowDefinition("");
+			fail("Should have bombed with illegal argument");
+		} catch (IllegalArgumentException e) {
+
+		}
+	}
+
 	public void testRegisterFlow() {
 		registry.registerFlowDefinition(new StaticFlowDefinitionHolder(fooFlow));
 		assertEquals(fooFlow, registry.getFlowDefinition("foo"));