518: Picking prototype (v6)

* PickingCandidateCommand: 
solve problem that the HU was created, but no qty was picked; thx
@teosarca
* WEBUI_Picking_PickToNewHU: avoid being called with non-picking-slot
item
* WEBUI_Picking_M_Picking_Candidate_Processed: minor

Task-Url: #518

src/main/java/de/metas/ui/web/picking/PickingCandidateCommand.java

@@ -13,7 +13,6 @@
 import org.compiere.model.IQuery;
 import org.compiere.model.I_C_UOM;
 import org.compiere.model.I_M_Product;
-import org.compiere.util.Env;
 import org.slf4j.Logger;
 import org.springframework.stereotype.Service;
 
@@ -128,7 +127,7 @@ public Quantity addQtyToHU(
 		}
 
 		final I_M_ShipmentSchedule shipmentSchedule = InterfaceWrapperHelper.load(shipmentScheduleId, I_M_ShipmentSchedule.class);
-		I_M_Product product = shipmentSchedule.getM_Product();
+		final I_M_Product product = shipmentSchedule.getM_Product();
 
 		final I_M_Picking_Candidate candidate = getCreateCandidate(huId, pickingSlotId, shipmentScheduleId);
 
@@ -156,7 +155,9 @@ public Quantity addQtyToHU(
 		// Request
 		final IShipmentScheduleBL shipmentScheduleBL = Services.get(IShipmentScheduleBL.class);
 
-		final IMutableHUContext huContext = Services.get(IHUContextFactory.class).createMutableHUContextForProcessing(Env.getCtx());
+		// create the context with the tread-inherited transaction! Otherwise, the loader won't be able to access the HU's material item and therefore won't load anything!
+		final IMutableHUContext huContext = Services.get(IHUContextFactory.class).createMutableHUContextForProcessing();
+
 		final IAllocationRequest request = AllocationUtils.createAllocationRequestBuilder()
 				.setHUContext(huContext)
 				.setProduct(product)

src/main/java/de/metas/ui/web/picking/process/WEBUI_Picking_M_Picking_Candidate_Processed.java

@@ -22,7 +22,6 @@
 import de.metas.fresh.picking.service.IPackingContext;
 import de.metas.fresh.picking.service.IPackingService;
 import de.metas.fresh.picking.service.impl.HU2PackingItemsAllocator;
-import de.metas.handlingunits.IHUPickingSlotBL;
 import de.metas.handlingunits.IHandlingUnitsBL;
 import de.metas.handlingunits.model.I_M_HU;
 import de.metas.handlingunits.model.I_M_Picking_Candidate;

src/main/java/de/metas/ui/web/picking/process/WEBUI_Picking_PickToNewHU.java

@@ -85,6 +85,12 @@ protected ProcessPreconditionsResolution checkPreconditionsApplicable()
 			return ProcessPreconditionsResolution.rejectBecauseNotSingleSelection();
 		}
 
+		final PickingSlotRow pickingSlotRow = getSingleSelectedRow();
+		if (!pickingSlotRow.isPickingSlotRow())
+		{
+			return ProcessPreconditionsResolution.reject(msgBL.getTranslatableMsgText("WEBUI_Picking_SelectPickingSlot"));
+		}
+
 		return ProcessPreconditionsResolution.accept();
 	}
 
@@ -164,13 +170,20 @@ private static final I_M_Locator getPickingSlotLocator(final PickingSlotRow pick
 		final int pickingSlotWarehouseId = pickingSlotRow.getPickingSlotWarehouseId();
 		if (pickingSlotWarehouseId <= 0)
 		{
-			throw new AdempiereException("Picking slot has no warehouse configured");
+			throw new AdempiereException("Picking slot with M_PickingSlot_ID=" + pickingSlotRow.getPickingSlotId() + " has no warehouse configured");
 		}
 		final I_M_Warehouse pickingSlotWarehouse = InterfaceWrapperHelper.loadOutOfTrx(pickingSlotWarehouseId, I_M_Warehouse.class);
 		final I_M_Locator pickingSlotLocator = Services.get(IWarehouseBL.class).getDefaultLocator(pickingSlotWarehouse);
 		return pickingSlotLocator;
 	}
 
+	/**
+	 * Creates a new M_HU within the processe's interited trx.
+	 * 
+	 * @param itemProduct
+	 * @param locator
+	 * @return
+	 */
 	private static final I_M_HU createTU(@NonNull final I_M_HU_PI_Item_Product itemProduct, @NonNull final I_M_Locator locator)
 	{
 		final IHandlingUnitsDAO handlingUnitsDAO = Services.get(IHandlingUnitsDAO.class);