Override ClassAttributeStorageFactory.flushAndClearCache

#10365
Signed-off-by: TheBestPessimist <cristian@tbp.land>

backend/de.metas.handlingunits.base/src/main/java/de/metas/handlingunits/IHUContext.java

@@ -104,5 +104,9 @@ public interface IHUContext extends IContextAware, IPropertiesContainer
 	/** @return previously added listeners that want to be notified before an empty HU is destroyed */
 	List<EmptyHUListener> getEmptyHUListeners();
 
+	/**
+	 * Flush the contents stored only in memory.
+	 * Useful for example to persist the HU Attributes.
+	 */
 	void flush();
 }

backend/de.metas.handlingunits.base/src/main/java/de/metas/handlingunits/attribute/storage/IAttributeStorageFactory.java

@@ -76,5 +76,5 @@ public interface IAttributeStorageFactory
 
 	void setHUStorageFactory(IHUStorageFactory huStorageFactory);
 
-	default void flushAndClearCache() {}
+	void flushAndClearCache();
 }

backend/de.metas.handlingunits.base/src/main/java/de/metas/handlingunits/attribute/storage/impl/AbstractModelAttributeStorageFactory.java

@@ -176,6 +176,7 @@ protected IAttributeStorage getAttributeStorageForModel(final ModelType model)
 	/**
 	 * Clears internal attribute storages cache and flushes pending saves on {@link #getHUAttributesDAO()}.
 	 */
+	@Override
 	public final void flushAndClearCache()
 	{
 		// First thing, clear the cached attribute storages.

backend/de.metas.handlingunits.base/src/main/java/de/metas/handlingunits/attribute/storage/impl/ClassAttributeStorageFactory.java

@@ -159,7 +159,7 @@ public IAttributeStorage getAttributeStorageIfHandled(final Object model)
 
 	@Override
 	public final IHUAttributesDAO getHUAttributesDAO()
-	{
+	{	 // TODO tbp: this exception is false: this.huAttributesDAO is NOT NULL!
 		throw new HUException("No IHUAttributesDAO found on " + this);
 	}
 
@@ -200,4 +200,13 @@ public IHUStorageFactory getHUStorageFactory()
 	{
 		return huStorageFactory;
 	}
+
+	@Override
+	public void flushAndClearCache()
+	{
+		if (huAttributesDAO != null)
+		{
+		huAttributesDAO.flushAndClearCache();
+		}
+	}
 }

backend/de.metas.handlingunits.base/src/main/java/de/metas/handlingunits/attribute/storage/impl/CompositeAttributeStorageFactory.java

@@ -214,6 +214,5 @@ public void flushAndClearCache()
 		{
 			factory.flushAndClearCache();
 		}
-		getHUAttributesDAO().flushAndClearCache();
 	}
 }