Hi Tomek, The SECA instinct is good — reacting to service events rather than editing receiveInventoryProduct is the right way to stay upgrade-safe. But before you build two services, I’d gently push back on where you’re putting the conversion, because doing it at receipt time is what creates most of the complexity you’re now having to engineer around.
I suggested converting at the stock move rather than at receipt because the two events answer different business questions: - The receipt has to reconcile against the supplier invoice. OFBiz generates purchase invoicing from ShipmentReceipt quantities, so the receipt, the PO, and the AP invoice all need to stay in the supplier’s unit (kg). If you convert at receipt, the inventory no longer sits in the unit your supplier billed you in, and the receipt no longer cleanly matches the invoice you’re paying. - The stock move into the warehouse is where the goods become your own on-hand to sell. That’s the natural and auditable point to switch into your stocking unit (g), because nothing upstream depends on it anymore. Your two-SECA design essentially recreates that switch at receipt, and the cost shows up in the very parts you’re already working around: - The “keep the old InventoryItem for history” step is the tell. You’re left with a zeroed-out kg item sitting next to the real g item, and every ATP rollup, cycle count, and inventory report then has to know to ignore it. At the stock move there’s no orphan — the quantity simply transfers and lands in the new unit. - The updateProduct trigger worries me most. Letting an admin edit Product.quantityUomId silently re-value stock you already own is an accounting event, not a form save. If there are reservations against that stock, the balances won’t reconcile, and you’d have no audit trail. I’d drop that path entirely and treat a UoM change on stocked product as a deliberate physical adjustment. So I’d still steer you toward the stock move: keep PO → receipt → InventoryItem all in kg, then put a single small service on the inventory transfer that calls convertUom (kg → g via UomConversion), records the on-hand in g, and stamps uomId. One conversion, one auditable point, no orphans, and the invoice reconciliation stays clean. The one part of your design I’d keep regardless is stamping uomId from the SupplierProduct on the freshly received item — that’s a nice touch and makes the kg stage explicit. Just resolve the supplier from the receipt or order context rather than from the bare InventoryItem, since createInventoryItem on its own won’t reliably know it’s part of a receipt. Best regards, Aditi On Thu, Jun 18, 2026 at 2:39 PM Tomek <[email protected]> wrote: > Hi, > > Thank you for proposing this solution. If I understand correctly, you > are suggesting to receive the goods (using the receiveInventoryProduct > service) and then somehow automatically perform the unit conversion > during the transfer order from the UI level? > > You mentioned that it is not advisable to modify data inside the > receiveInventoryProduct service. What do you think about using SECA > (Service ECA) rules instead? Rather than modifying the data within > receiveInventoryProduct itself, we could perform the conversion right > after this service executes. My concept relies on two additional ECA > services. The first one would be triggered after the createInventoryItem > service completes, and the second one after the receiveInventoryProduct > service completes. > > The first service (called after createInventoryItem) checks if the > InventoryItem is linked to a supplier and if its uomId == null. If so, > it sets the uomId based on the SupplierProduct's UOM. This ensures that > the InventoryItem stores the supplier's unit of measure. > > The second service (called after receiveInventoryProduct) would perform > the following steps: > > 1. Retrieve all InventoryItems that meet the following requirements: > - are linked to the given product > - have a UOM different from Product.quantityUomId > - the fields quantityOnHandTotal != 0 OR availableToPromiseTotal != 0 OR > accountingQuantityTotal != 0 > > If I sell the product in the same unit of measure as the supplier, this > InventoryItem list should be empty. Otherwise, usually one InventoryItem > element will appear (we could also trigger this ECA service after the > updateProduct service to detect if the Product.quantityUomId value has > changed — in that case, the number of elements on the InventoryItem list > would be greater). > > 2. For each InventoryItem element from the list created in step one: > - create an InventoryItemDetail that resets quantityOnHandTotal, > availableToPromiseTotal, and accountingQuantityTotal to zero in the > original InventoryItem. > - calculate the new quantityOnHandTotal, availableToPromiseTotal, > accountingQuantityTotal, and unitCost based on the original values (unit > conversion). For instance, when converting from WT_kg to WT_g, each of > these values would be multiplied by 1000, except for the cost, which > would be divided by 1000 (I would use the convertUom service you > mentioned earlier for this). This would result in new variables: > newQuantityOnHandTotal, newAvailableToPromiseTotal, > newAccountingQuantityTotal, and newUnitCost. > - create a new InventoryItem, set its uomId field to > Product.quantityUomId, and then add a new InventoryItemDetail record > (quantityOnHandDiff = newQuantityOnHandTotal, availableToPromiseDiff = > newAvailableToPromiseTotal, accountingQuantityDiff = > newAccountingQuantityTotal, unitCost = newUnitCost) linked to this new > InventoryItem. > > The outcome of the above algorithm will be the creation of a new > InventoryItem based on the desired units of measure. The old > InventoryItem will be kept purely for informational/historical purposes > (it will no longer contain any available products). > > What do you think about this approach? > > Best regards, > Tomek > > W dniu 16.06.2026 o 17:38, Aditi Patel pisze: > > Hi Tomek, > > > > Glad the earlier note helped. Here is how I would suggest handling UoM > > across the lifecycle. > > > > The cleanest pattern is to keep the purchasing side in the supplier's > unit > > and switch to your stocking unit only when goods enter the warehouse. The > > PO carries the supplier product's UoM (copied from SupplierProduct, e.g. > > kg), the shipment is received in that same UoM, and the InventoryItem is > > created in the UoM from the ShipmentReceipt. When you then move that > stock > > into the warehouse, you convert using the SupplierProduct and Product > UoMs > > and stock it in the Product's UoM (g). > > > > PO (kg) -> Receipt (kg) -> InventoryItem (kg) -> Stock move to warehouse, > > convert kg -> g -> On-hand and sales in g > > > > So the PO lifecycle stays in the supplier product's UoM and the stocking > is > > in the product's UoM, with the conversion happening at the stock move. > > Receiving in the PO's unit also keeps a clean match between the PO, the > > receipt, and the supplier invoice (OFBiz generates purchase invoicing > from > > ShipmentReceipt quantities), so AP reconciliation and unit cost stay > > accurate. > > > > On your questions: > > > > 1. The data model does support UoM management at the inventory level, and > > InventoryItem.uomId is part of that - I have seen it used across various > > inventory flows, including receiving, to record the unit an item is held > > in. Just keep in mind the core ATP/QOH and reservation logic does not > read > > it out of the box, so it labels the unit rather than driving the > conversion > > on its own. > > > > 2. There is no single enforced "stocking UoM" field - inventory is > > effectively 1 unit = 1. By convention the stocking unit lives on > > Product.quantityUomId, the supplier's unit on > > SupplierProduct.quantityUomId, and the conversion factor (wt_kg -> wt_g = > > 1000) in the UomConversion entity that convertUom reads. > > > > 3. Rather than converting inside receiveInventoryProduct, I would do it > at > > the stock move into the warehouse: a small service (for example in a > > hot-deploy component, around the inventory transfer / stock move) that > > calls convertUom using the SupplierProduct and Product UoMs, records the > > on-hand in g, and stamps InventoryItem.uomId. Everything downstream then > > stays consistent. > > > > If at any point the UoM management or the conversions are not behaving as > > expected, feel free to reach out - happy to help. > > > > Best regards, > > Aditi > > > > On Tue, Jun 16, 2026 08:17 PM, Tomek <[email protected]> wrote: > > > >> Hi, > >> > >> Thank you very much for your response. > >> > >> Indeed, this issue can be managed by: > >> - multiplying the quantity by 1000 and dividing the cost by 1000 during > >> the purchase order receipt, > >> - multiplying the quantity by 1000 and dividing the cost by 1000 at the > >> stage of purchase order creation. > >> > >> This works and is actually a viable solution, but it makes me wonder: > >> what is the purpose of the uomId field in InventoryItem then? Is it used > >> anywhere at all? Is it a legacy remnant or perhaps a placeholder > >> designed for future process customization? > >> > >> Let's assume I would like to automatically convert units from the > >> supplier's purchase unit to my own preferred unit. For instance, I store > >> Product X in my warehouse in grams, but the supplier sells it in > >> kilograms. I would like this conversion to happen automatically. > >> > >> With that in mind, I have a couple of questions: > >> > >> 1. Where should I define my internal stocking unit (the UoM for products > >> stored in my own warehouse)? > >> 2. What would be the best way to handle this conversion? Should I > >> override the receiveInventoryProduct service, or is there a better, more > >> recommended approach? > >> > >> Best regards, > >> Tomek > >> > >> W dniu 16.06.2026 o 13:06, Aditi Patel pisze: > >>> Hi, > >>> > >>> Thanks for the clear write-up and reproduction steps! The good news is > >> that > >>> nothing is broken here. What you are seeing is OFBiz working as > designed: > >>> it does not perform automatic unit-of-measure conversion across the > >>> purchase -> inventory -> sales flow. > >>> > >>> A few things that explain both observations: > >>> > >>> - Inventory is counted in stocking units, not by weight. ATP and QOH > are > >>> plain numeric quantities with no associated UoM, and reservation simply > >>> subtracts the ordered quantity. That is why selling 1 reduces ATP by > >>> exactly 1 rather than 0.25. > >>> - receiveInventoryProduct does not copy Product.quantityUomId or the > >>> SupplierProduct UoM onto InventoryItem.uomId, so it is left null. And > >> even > >>> when you set it manually, the reservation logic never reads it, so the > >> math > >>> is unchanged. > >>> - Product.quantityIncluded / quantityUomId are descriptive packaging > >>> metadata, not conversion factors applied to inventory or orders. > >>> > >>> So both behaviors are expected rather than a bug. If you need to buy in > >> one > >>> unit and stock or sell in another, the cleanest options are: > >>> > >>> - Normalize everything to a single stocking UoM and convert at receipt > >>> time, e.g. receive the 1 kg PO line as quantityAccepted = 1000 and keep > >> the > >>> product stocked in grams; or > >>> - Add your own conversion using the convertUom service together with > the > >>> UomConversion entity in framework/common. > >>> > >>> Hope this helps clear things up, and happy to elaborate on any of the > >> above. > >>> Best regards, > >>> Aditi Patel > >>> > >>> On Tue, Jun 16, 2026 04:15 PM, Tomek <[email protected]> wrote: > >>> > >>>> Hi everyone, > >>>> > >>>> I am facing an issue with UoM (Unit of Measure) handling in OFBiz and > >>>> would appreciate some guidance. > >>>> > >>>> Here is my setup and the steps to reproduce the issue: > >>>> > >>>> 1. I created a test product and configured it with: > >>>> - Quantity Included: 250 > >>>> - Quantity Uom Id: Grams (wt_g) > >>>> > >>>> 2. In the Suppliers tab, I added a supplier and set their supplier UoM > >>>> to Kilograms (wt_kg). > >>>> > >>>> 3. I created a Purchase Order (PO) from this supplier, who sells the > >>>> item in wt_kg. > >>>> > >>>> 4. I received the shipment for this PO, which automatically created an > >>>> InventoryItem. > >>>> > >>>> Problem: > >>>> > >>>> The uomId field in the newly created InventoryItem was not populated > (it > >>>> is null). > >>>> > >>>> Next, I simulated a sales order for this test product. After adding > the > >>>> product to the order and approving it, the system decreased the > >>>> Available To Promise (ATP) on the aforementioned InventoryItem by > >> exactly > >>>> 1. > >>>> > >>>> This issue persists even if I manually update the uomId field to wt_kg > >>>> directly in the InventoryItem. > >>>> > >>>> Questions: > >>>> > >>>> 1. Why does OFBiz seem to ignore the Units of Measure in this > scenario? > >>>> > >>>> 2. Shouldn't the sales order reduce the ATP value by 0.25 instead of > 1, > >>>> given the product configuration? > >>>> > >>>> Any insights on what might be missing or if this is an out-of-the-box > >>>> limitation would be highly appreciated. > >>>> > >>>> Thanks in advance! > >>>> > >>>> >
