refactoring object model

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

core/src/main/java/de/srsoftware/umbrella/core/ModuleRegistry.java

@@ -89,6 +89,8 @@ public class ModuleRegistry {
 		return singleton.projectService;
 	}
 
+	public static StockService stockService() { return singleton.stockService; }
+
 	public static TagService tagService(){
 		return singleton.tagService;
 	}

core/src/main/java/de/srsoftware/umbrella/core/api/LocationRef.java

@@ -1,10 +0,0 @@
-/* © SRSoftware 2025 */
-package de.srsoftware.umbrella.core.api;
-
-import de.srsoftware.tools.Mappable;
-import de.srsoftware.umbrella.core.model.Location;
-
-public interface LocationRef extends Mappable {
-	Location resolve(StockService stockService);
-	long id();
-}

core/src/main/java/de/srsoftware/umbrella/core/api/Owner.java

@@ -1,6 +1,16 @@
 /* © SRSoftware 2025 */
 package de.srsoftware.umbrella.core.api;
 
-public interface Owner {
+import static de.srsoftware.umbrella.core.Constants.*;
-	long signum();
+
+import de.srsoftware.tools.Mappable;
+
+public interface Owner extends Mappable {
+	public static final String SEPARATOR = ":";
+	default String dbCode(){
+		return type()+SEPARATOR+id();
+	}
+	long id();
+	String type();
+	public Owner resolve();
 }

core/src/main/java/de/srsoftware/umbrella/core/api/OwnerRef.java

@@ -1,10 +0,0 @@
-/* © SRSoftware 2025 */
-package de.srsoftware.umbrella.core.api;
-
-import de.srsoftware.tools.Mappable;
-import de.srsoftware.umbrella.core.ModuleRegistry;
-
-public interface OwnerRef extends Mappable {
-	long id();
-	Owner resolve(ModuleRegistry registry);
-}

core/src/main/java/de/srsoftware/umbrella/core/api/StockService.java

@@ -2,6 +2,7 @@
 package de.srsoftware.umbrella.core.api;
 
 
+import de.srsoftware.umbrella.core.model.DbLocation;
 import java.util.Collection;
 
 public interface StockService {
@@ -12,4 +13,6 @@ public interface StockService {
 	 * @return
 	 */
 	Collection<Object> redefineMe(long company_id);
+
+	DbLocation loadLocation(long locationId);
 }

core/src/main/java/de/srsoftware/umbrella/core/model/Company.java

@@ -6,6 +6,7 @@ import static de.srsoftware.umbrella.core.Constants.*;
 import static java.util.Map.entry;
 
 import de.srsoftware.tools.Mappable;
+import de.srsoftware.umbrella.core.api.Owner;
 import de.srsoftware.umbrella.core.exceptions.UmbrellaException;
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -13,7 +14,7 @@ import java.util.*;
 import org.json.JSONException;
 import org.json.JSONObject;
 
-public class Company implements Mappable {
+public class Company implements Mappable, Owner {
 	private final long id;
 	private String name, address, court, taxId, phone, decimalSeparator, thousandsSeparator,  customerNumberPrefix, currency, email, bankAccount;;
 	private long lastCustomerNumber;
@@ -80,7 +81,8 @@ public class Company implements Mappable {
 		return email;
 	}
 
-	public long id(){
+	@Override
+	public long id() {
 		return id;
 	}
 
@@ -162,6 +164,11 @@ public class Company implements Mappable {
 		return phone;
 	}
 
+	@Override
+	public Owner resolve() {
+		return this;
+	}
+
 	public String taxId() {
 		return taxId;
 	}
@@ -182,7 +189,6 @@ public class Company implements Mappable {
 			memberMap.put(entry.getKey(),entry.getValue().toMap());
 		}
 		return Map.ofEntries(
-				entry(ID,id),
 				entry(NAME,name),
 				entry(ADDRESS,emptyIfNull(address)),
 				entry(FIELD_COURT,emptyIfNull(court)),
@@ -196,8 +202,14 @@ public class Company implements Mappable {
 				entry(FIELD_CURRENCY,emptyIfNull(currency)),
 				entry(EMAIL,emptyIfNull(email)),
 				entry(FIELD_BANK_ACCOUNT,emptyIfNull(bankAccount)),
-				entry(MEMBERS,memberMap)
+				entry(MEMBERS,memberMap),
-		);
+				entry(TYPE,type()),
+				entry(ID,id)
+			);
 	}
 
+	@Override
+	public String type() {
+		return COMPANY;
+	}
 }

core/src/main/java/de/srsoftware/umbrella/core/model/DbLocation.java

@@ -0,0 +1,61 @@
+/* © SRSoftware 2025 */
+package de.srsoftware.umbrella.core.model;
+
+import static de.srsoftware.umbrella.core.Constants.*;
+
+import de.srsoftware.umbrella.core.api.Owner;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.Map;
+
+public class DbLocation extends Location {
+	private Owner owner;
+	private Long parentLocationId;
+	private String name;
+	private String description;
+	private String relation; // when added to an item, this field describes the type of the relation
+
+	private DbLocation(long id, Owner owner, Long parentLocationId, String name, String description){
+		super(id);
+		this.owner = owner;
+		this.parentLocationId = parentLocationId;
+		this.name = name;
+		this.description = description;
+	}
+
+	public String description() {
+		return description;
+	}
+
+	public String name() {
+		return name;
+	}
+
+	public static DbLocation of(ResultSet rs) throws SQLException {
+
+		return new DbLocation(rs.getLong(ID), OwnerRef.of(rs), rs.getLong(PARENT_LOCATION_ID), rs.getString(NAME),rs.getString(DESCRIPTION));
+	}
+
+	public Long parent(){
+		return parentLocationId;
+	}
+
+	@Override
+	public DbLocation resolve() {
+		return this;
+	}
+
+	@Override
+	public Map<String, Object> toMap() {
+		return Map.of(
+				OWNER,owner.toMap(),
+				ID,id(),
+				NAME,name,
+				DESCRIPTION,description);
+	}
+
+	@Override
+	public String toString() {
+		return name;
+	}
+}

core/src/main/java/de/srsoftware/umbrella/core/model/Item.java

@@ -4,8 +4,7 @@ package de.srsoftware.umbrella.core.model;
 import static de.srsoftware.umbrella.core.Constants.*;
 
 import de.srsoftware.tools.Mappable;
-import de.srsoftware.umbrella.core.api.LocationRef;
+import de.srsoftware.umbrella.core.api.Owner;
-import de.srsoftware.umbrella.core.api.OwnerRef;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.*;
@@ -13,17 +12,17 @@ import org.json.JSONObject;
 
 public class Item implements Mappable {
 	private long id, number; // id is the database key, number the owner-relative id
-	private OwnerRef ownerRef;
+	private Owner owner;
 	private String code, name;
-	private LocationRef locationRef;
+	private Location location;
 	private Collection<Property> properties;
 	private Set<String> dirtyFields = new HashSet<>();
 
-	private Item(long id, OwnerRef ownerRef, long number, LocationRef locationRef, String code, String name) {
+	private Item(long id, Owner owner, long number, Location location, String code, String name) {
 		this.id = id;
-		this.ownerRef = ownerRef;
+		this.owner = owner;
 		this.number = number;
-		this.locationRef = locationRef;
+		this.location = location;
 		this.code = code;
 		this.name = name;
 		this.properties = new HashSet<>();
@@ -41,23 +40,26 @@ public class Item implements Mappable {
 		return id;
 	}
 
-	public LocationRef location(){
+	public Location location(){
-		return locationRef;
+		return location;
 	}
 
 	public String name(){
 		return name;
 	}
 
-	public static Item of(ResultSet rs, OwnerRef ownerRef, long number, LocationRef locationRef) throws SQLException {
+	public static Item of(ResultSet rs) throws SQLException {
 		var id = rs.getLong(ID);
 		var code = rs.getString(CODE);
 		var name = rs.getString(NAME);
-		return new Item(id, ownerRef, number, locationRef, code, name);
+		var owner = OwnerRef.of(rs);
+		var number = rs.getLong(NUMBER);
+		var location = Location.of(rs);
+		return new Item(id, owner, number, location, code, name);
 	}
 
-	public OwnerRef ownerRef(){
+	public Owner owner(){
-		return ownerRef;
+		return owner;
 	}
 
 	public Collection<Property> properties() {
@@ -67,9 +69,9 @@ public class Item implements Mappable {
 	@Override
 	public Map<String, Object> toMap() {
 		var map = new HashMap<String,Object>();
-		map.put(OWNER,ownerRef.toMap());
+		map.put(OWNER,owner.toMap());
 		map.put(ID,id);
-		map.put(LOCATION,locationRef.toMap());
+		map.put(LOCATION,location.toMap());
 		map.put(CODE,code);
 		map.put(NAME,name);
 		if (properties != null) map.put(PROPERTIES,properties.stream().map(Property::toMap).toList());

core/src/main/java/de/srsoftware/umbrella/core/model/Location.java

@@ -1,72 +1,48 @@
 /* © SRSoftware 2025 */
 package de.srsoftware.umbrella.core.model;
 
-import static de.srsoftware.umbrella.core.Constants.*;
+import static de.srsoftware.umbrella.core.Constants.ID;
+import static de.srsoftware.umbrella.core.Constants.LOCATION_ID;
+import static de.srsoftware.umbrella.core.ModuleRegistry.stockService;
+import static java.text.MessageFormat.format;
 
 import de.srsoftware.tools.Mappable;
+
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.Map;
 
 public class Location implements Mappable {
-	private long owner;
-	private boolean ownerIsCompany = false;
-	private long id;
-	private Long parentLocationId;
-	private String name;
-	private String description;
-	private String relation; // when added to an item, this field describes the type of the relation
-
-	private Location(long owner, boolean ownerIsCompany, long id, Long parentLocationId, String name, String description){
-		this.owner = owner;
-		this.ownerIsCompany = ownerIsCompany;
-		this.id = id;
-		this.parentLocationId = parentLocationId;
-		this.name = name;
-		this.description = description;
-	}
-
-	public final long id(){
-		return id;
-	}
 
-	public String description() {
+	private final long id;
-		return description;
-	}
 
-	public String name() {
+	public Location(long id){
-		return name;
+		this.id = id;
 	}
 
 	public static Location of(ResultSet rs) throws SQLException {
-		var owner = rs.getLong(OWNER);
+		return new Location(rs.getLong(LOCATION_ID));
-		var id = rs.getLong(ID);
-		var isCompany = owner < 0;
-		if (isCompany) owner = -owner;
-		return new Location(owner,isCompany,id, rs.getLong(PARENT_LOCATION_ID), rs.getString(NAME),rs.getString(DESCRIPTION));
 	}
 
+	public static Location of(long locationId) {
+		return new Location(locationId);
+	}
 
-
+	public DbLocation resolve(){
-	public long ownerCoded(){
+		return stockService().loadLocation(id());
-		return ownerIsCompany ? -owner : owner;
 	}
 
-	public Long parent(){
+	public long id(){
-		return parentLocationId;
+		return id;
 	}
 
 	@Override
 	public Map<String, Object> toMap() {
-		return Map.of(
+		return Map.of(ID,id);
-				ownerIsCompany ? COMPANY : USER,owner,
-				ID,id,
-				NAME,name,
-				DESCRIPTION,description);
 	}
 
 	@Override
 	public String toString() {
-		return name;
+		return format("Location({0})",id);
 	}
 }

core/src/main/java/de/srsoftware/umbrella/core/model/OwnerRef.java

@@ -0,0 +1,73 @@
+/* © SRSoftware 2025 */
+package de.srsoftware.umbrella.core.model;
+
+import static de.srsoftware.umbrella.core.Constants.*;
+import static de.srsoftware.umbrella.core.Constants.ID;
+import static de.srsoftware.umbrella.core.ModuleRegistry.companyService;
+import static de.srsoftware.umbrella.core.ModuleRegistry.userService;
+import static de.srsoftware.umbrella.core.exceptions.UmbrellaException.unprocessable;
+
+import de.srsoftware.umbrella.core.api.Owner;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.HashMap;
+import java.util.Map;
+
+public class OwnerRef implements Owner {
+
+	private final String type;
+	private final long id;
+
+	public OwnerRef(String dbCode){
+		var parts = dbCode.split(":");
+		if (parts.length != 2) throw unprocessable("Encountered invalid dbCode: {0}",dbCode);
+		type = parts[0];
+		try {
+			id = Long.parseLong(parts[1]);
+		} catch (NumberFormatException e) {
+			throw unprocessable("Encountered invalid dbCode: {0}",dbCode);
+		}
+	}
+
+	public OwnerRef(String type, long id){
+		this.type = type;
+		this.id   = id;
+	}
+
+	public static Owner of(ResultSet rs) throws SQLException {
+		return new OwnerRef(rs.getString(OWNER));
+	}
+
+	public String dbCode(){
+		return type+SEPARATOR+id;
+	}
+
+	public long id(){
+		return id;
+	}
+
+	public String type(){
+		// TODO: is this needed?
+		return type;
+	}
+
+	/**
+	 * returns the actual owner object
+	 * @return the actual owner object
+	 */
+	public Owner resolve(){
+		return switch (type){
+			case COMPANY -> companyService().get(id());
+			case USER    -> userService().loadUser(id());
+			case null, default -> throw unprocessable("Encountered invalid owner type: {0}",type);
+		};
+	}
+
+	@Override
+	public Map<String, Object> toMap() {
+		var map = new HashMap<String,Object>();
+		map.put(TYPE,type);
+		map.put(ID, id);
+		return map;
+	}
+}

core/src/main/java/de/srsoftware/umbrella/core/model/UmbrellaUser.java

@@ -5,12 +5,13 @@ package de.srsoftware.umbrella.core.model;
 import static de.srsoftware.umbrella.core.Constants.*;
 
 import de.srsoftware.tools.Mappable;
+import de.srsoftware.umbrella.core.api.Owner;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Objects;
 
 /* © SRSoftware 2025 */
-public class UmbrellaUser extends User implements Mappable {
+public class UmbrellaUser extends User implements Mappable, Owner {
 
 	private final long id;
 	private final String theme;
@@ -21,7 +22,6 @@ public class UmbrellaUser extends User implements Mappable {
 		this.theme = theme;
 	}
 
-
 	@Override
 	public boolean equals(Object o) {
 		if (!(o instanceof UmbrellaUser user)) return false;
@@ -40,6 +40,11 @@ public class UmbrellaUser extends User implements Mappable {
 		return id;
 	}
 
+	@Override
+	public Owner resolve() {
+		return this;
+	}
+
 	public String theme(){
 		return theme;
 	}
@@ -55,4 +60,9 @@ public class UmbrellaUser extends User implements Mappable {
 		map.put(LANGUAGE,language());
 		return map;
 	}
+
+	@Override
+	public String type() {
+		return USER;
+	}
 }

stock/src/main/java/de/srsoftware/umbrella/stock/SqliteDb.java

@@ -7,8 +7,6 @@ import static de.srsoftware.tools.jdbc.Condition.isNull;
 import static de.srsoftware.tools.jdbc.Query.*;
 import static de.srsoftware.tools.jdbc.Query.SelectQuery.ALL;
 import static de.srsoftware.umbrella.core.Constants.*;
-import static de.srsoftware.umbrella.core.ModuleRegistry.companyService;
-import static de.srsoftware.umbrella.core.ModuleRegistry.userService;
 import static de.srsoftware.umbrella.core.exceptions.UmbrellaException.databaseException;
 import static de.srsoftware.umbrella.stock.Constants.*;
 import static java.lang.System.Logger.Level.ERROR;
@@ -17,6 +15,7 @@ import static java.text.MessageFormat.format;
 
 import de.srsoftware.tools.Mappable;
 import de.srsoftware.umbrella.core.BaseDb;
+import de.srsoftware.umbrella.core.model.Location;
 import de.srsoftware.umbrella.core.model.*;
 import java.sql.Connection;
 import java.sql.ResultSet;
@@ -195,11 +194,11 @@ public class SqliteDb extends BaseDb implements StockDb {
 	}
 
 	@Override
-	public Collection<Location> listChildLocations(long parentId) {
+	public Collection<DbLocation> listChildLocations(long parentId) {
 		try {
 			var rs = select(ALL).from(TABLE_LOCATIONS).where(PARENT_LOCATION_ID,equal(parentId)).exec(db);
-			var list = new ArrayList<Location>();
+			var list = new ArrayList<DbLocation>();
-			while (rs.next()) list.add(Location.of(rs));
+			while (rs.next()) list.add(DbLocation.of(rs));
 			rs.close();
 			return list;
 		} catch (SQLException e){
@@ -208,11 +207,11 @@ public class SqliteDb extends BaseDb implements StockDb {
 	}
 
 	@Override
-	public Collection<Location> listCompanyLocations(Company company) {
+	public Collection<DbLocation> listCompanyLocations(Company company) {
 		try {
 			var rs = select(ALL).from(TABLE_LOCATIONS).where(OWNER,equal(-company.id())).where(PARENT_LOCATION_ID,isNull()).exec(db);
-			var list = new ArrayList<Location>();
+			var list = new ArrayList<DbLocation>();
-			while (rs.next()) list.add(Location.of(rs));
+			while (rs.next()) list.add(DbLocation.of(rs));
 			rs.close();
 			return list;
 		} catch (SQLException e){
@@ -221,41 +220,32 @@ public class SqliteDb extends BaseDb implements StockDb {
 	}
 
 	@Override
-	public Collection<Item> listItemsAt(long locationId) {
+	public Collection<Item> listItemsAt(Location location) {
 		try {
-			var location = loadLocation(locationId);
+			var rs = select(ALL).from(TABLE_ITEMS).where(LOCATION_ID,equal(location.id())).exec(db);
-			var rs = select(ALL).from(TABLE_ITEMS).where(LOCATION_ID,equal(locationId)).exec(db);
 			var list = new ArrayList<Item>();
 			var ownerMap = new HashMap<Long,Mappable>();
-			while (rs.next()) {
+			while (rs.next()) list.add(Item.of(rs));
-				var ownerId = rs.getLong(OWNER);
-				var owner = ownerMap.get(ownerId);
-				if (owner == null) {
-					owner = ownerId < 0 ? companyService().get(-ownerId) : userService().loadUser(ownerId);
-					ownerMap.put(ownerId,owner);
-				}
-				list.add(Item.of(rs, owner, location));
-			}
 			rs.close();
 
 			for (var item : list){
-				var ownerId = item.ownerId();
+				var ownerId = item.owner();
 				rs = select(ALL).from(TABLE_ITEM_PROPERTIES).leftJoin(PROPERTY_ID,TABLE_PROPERTIES,ID).where(OWNER,equal(ownerId)).where(ITEM_ID,equal(item.id())).exec(db);
 				while (rs.next()) item.properties().add(Property.of(rs));
 				rs.close();
 			}
 			return list;
 		} catch (SQLException e){
-			throw databaseException("Failed to load items at {0}",locationId);
+			throw databaseException("Failed to load items at {0}",location);
 		}
 	}
 
 	@Override
-	public Item loadItem(Mappable owner, long itemId) {
+	public Item loadItem(long id) {
 		try {
-			var rs = select(ALL).from(TABLE_ITEMS).where(OWNER,equal(Item.ownerId(owner))).where(ID,equal(itemId)).exec(db);
+			var rs = select(ALL).from(TABLE_ITEMS).where(ID,equal(id)).exec(db);
 			Item result = null;
-			if (rs.next()) result = Item.of(rs,owner,null);
+			if (rs.next()) result = Item.of(rs);
 			rs.close();
 			if (result != null) return result;
 		} catch (SQLException ignored) {
@@ -263,11 +253,11 @@ public class SqliteDb extends BaseDb implements StockDb {
 		throw databaseException("Failed to load item");
 	}
 
-	private Location loadLocation(long locationId) {
+	public DbLocation loadLocation(long locationId) {
 		try {
 			var rs = select(ALL).from(TABLE_LOCATIONS).where(ID,equal(locationId)).exec(db);
-			Location loc = null;
+			DbLocation loc = null;
-			if (rs.next()) loc = Location.of(rs);
+			if (rs.next()) loc = DbLocation.of(rs);
 			rs.close();
 			if (loc != null) return loc;
 			throw databaseException("Failed to load location with id = {0}",locationId);
@@ -290,11 +280,11 @@ public class SqliteDb extends BaseDb implements StockDb {
 	}
 
 	@Override
-	public Collection<Location> listUserLocations(UmbrellaUser user) {
+	public Collection<DbLocation> listUserLocations(UmbrellaUser user) {
 		try {
 			var rs = select(ALL).from(TABLE_LOCATIONS).where(OWNER,equal(user.id())).where(PARENT_LOCATION_ID,isNull()).exec(db);
-			var list = new ArrayList<Location>();
+			var list = new ArrayList<DbLocation>();
-			while (rs.next()) list.add(Location.of(rs));
+			while (rs.next()) list.add(DbLocation.of(rs));
 			rs.close();
 			return list;
 		} catch (SQLException e){
@@ -324,7 +314,7 @@ public class SqliteDb extends BaseDb implements StockDb {
 		} else if (item.isDirty()) {
 			try {
 				var location = item.location();
-				var query = update(TABLE_ITEMS).where(OWNER, equal(item.ownerId())).where(ID, equal(item.id()));
+				var query = update(TABLE_ITEMS).where(ID, equal(item.id()));
 				if (location == null) {
 					query.set(CODE,NAME);
 				} else {

stock/src/main/java/de/srsoftware/umbrella/stock/StockDb.java

@@ -1,18 +1,19 @@
 /* © SRSoftware 2025 */
 package de.srsoftware.umbrella.stock;
 
-import de.srsoftware.tools.Mappable;
+import de.srsoftware.umbrella.core.model.Location;
 import de.srsoftware.umbrella.core.model.*;
 import java.util.Collection;
 
 public interface StockDb {
 	Property addNewProperty(long ownerId, long itemId, String name, Object value, String unit);
-	Collection<Location> listChildLocations(long parentId);
+	Collection<DbLocation> listChildLocations(long parentId);
-	Collection<Location> listCompanyLocations(Company company);
+	Collection<DbLocation> listCompanyLocations(Company company);
-	Collection<Item>     listItemsAt(long locationId);
+	Collection<Item>     listItemsAt(Location location);
 	Collection<Property> listProperties();
-	Collection<Location> listUserLocations(UmbrellaUser userId);
+	Collection<DbLocation> listUserLocations(UmbrellaUser userId);
-	Item loadItem(Mappable owner, long itemId);
+	Item loadItem(long id);
+	DbLocation loadLocation(long locationId);
 	Item save(Item item);
 	Property setProperty(long ownerId, long itemId, long existingPropId, Object value);
 }

stock/src/main/java/de/srsoftware/umbrella/stock/StockModule.java

@@ -19,6 +19,7 @@ import de.srsoftware.tools.Path;
 import de.srsoftware.tools.SessionToken;
 import de.srsoftware.umbrella.core.BaseHandler;
 import de.srsoftware.umbrella.core.ModuleRegistry;
+import de.srsoftware.umbrella.core.model.Location;
 import de.srsoftware.umbrella.core.api.StockService;
 import de.srsoftware.umbrella.core.exceptions.UmbrellaException;
 import de.srsoftware.umbrella.core.model.*;
@@ -49,7 +50,7 @@ public class StockModule extends BaseHandler implements StockService {
 				case LOCATION -> {
 					try {
 						var id = Long.parseLong(path.pop());
-						yield getLocation(user.get(),id,ex);
+						yield getLocation(user.get(), Location.of(id),ex);
 					} catch (Exception e){
 						yield super.doGet(path,ex);
 					}
@@ -95,12 +96,12 @@ public class StockModule extends BaseHandler implements StockService {
 
 	private boolean getChildLocations(UmbrellaUser user, long parentId, HttpExchange ex) throws IOException {
 		LOG.log(WARNING,"No security check implemented for {0}.getChildLocations(user, parentId, ex)!",getClass().getSimpleName()); // TODO check, that user is allowed to request that location
-		return sendContent(ex, stockDb.listChildLocations(parentId).stream().sorted(comparing(l -> l.name().toLowerCase())).map(Location::toMap));
+		return sendContent(ex, stockDb.listChildLocations(parentId).stream().sorted(comparing(l -> l.name().toLowerCase())).map(DbLocation::toMap));
 
 	}
 
-	private boolean getLocation(UmbrellaUser user, long locationId, HttpExchange ex) throws IOException {
+	private boolean getLocation(UmbrellaUser user, Location location, HttpExchange ex) throws IOException {
-		return sendContent(ex, stockDb.listItemsAt(locationId).stream().map(Item::toMap).toList());
+		return sendContent(ex, stockDb.listItemsAt(location).stream().map(Item::toMap).toList());
 	}
 
 	private boolean getLocations(Path path, UmbrellaUser user, HttpExchange ex) throws IOException {
@@ -130,7 +131,7 @@ public class StockModule extends BaseHandler implements StockService {
 		result.add(Map.of(
 				ID, user.id(),
 				NAME,user.name(),
-				LOCATIONS,userLocations.stream().map(Location::toMap).toList()));
+				LOCATIONS,userLocations.stream().map(DbLocation::toMap).toList()));
 
 		var companies = companyService().listCompaniesOf(user);
 		companies.values().stream().sorted(comparing(a -> a.name().toLowerCase())).forEach(company -> {
@@ -138,37 +139,27 @@ public class StockModule extends BaseHandler implements StockService {
 					result.add(Map.of(
 							ID, company.id(),
 							NAME,company.name(),
-							LOCATIONS,locations.stream().sorted(comparing(a -> a.name().toLowerCase())).map(Location::toMap).toList()));
+							LOCATIONS,locations.stream().sorted(comparing(a -> a.name().toLowerCase())).map(DbLocation::toMap).toList()));
 
 				});
 		return sendContent(ex, result);
 	}
 
+	@Override
+	public DbLocation loadLocation(long locationId) {
+		return stockDb.loadLocation(locationId);
+	}
+
 	private boolean patchItem(UmbrellaUser user, HttpExchange ex) throws IOException {
 		var json = json(ex);
 		if (!(json.get(ID) instanceof Number id)) throw missingFieldException(ID);
-		if (!(json.get(OWNER) instanceof JSONObject ownerRef)) throw missingFieldException(OWNER);
 		json.remove(ID);
-		json.remove(OWNER);
-		var owner = toOwner(ownerRef);
 
-		var item = stockDb.loadItem(owner,id.longValue());
+		var item = stockDb.loadItem(id.longValue());
 		item.patch(json);
 		return sendContent(ex,stockDb.save(item));
 	}
 
-	private Mappable toOwner(JSONObject owner) {
-		var keys = owner.keySet();
-		if (keys.size() != 1) throw unprocessable("{0} expected to have only one child!",OWNER);
-		String key = new ArrayList<>(keys).getFirst();
-		return switch (key) {
-			case COMPANY -> companyService().get(owner.getLong(key));
-			case USER -> userService().loadUser(owner.getLong(key));
-			default -> throw invalidFieldException(format("Single child of {0}", OWNER), format("either {0} or {1}", COMPANY, USER));
-		};
-
-	}
-
 	private boolean postProperty(UmbrellaUser user, HttpExchange ex) throws IOException {
 		var json = json(ex);
 		if (!(json.get(FIELD_ITEM) instanceof JSONObject itemData)) throw missingFieldException(FIELD_ITEM);
@@ -192,6 +183,18 @@ public class StockModule extends BaseHandler implements StockService {
 		return sendContent(ex,property);
 	}
 
+	private Mappable toOwner(JSONObject owner) {
+		var keys = owner.keySet();
+		if (keys.size() != 1) throw unprocessable("{0} expected to have only one child!",OWNER);
+		String key = new ArrayList<>(keys).getFirst();
+		return switch (key) {
+			case COMPANY -> companyService().get(owner.getLong(key));
+			case USER -> userService().loadUser(owner.getLong(key));
+			default -> throw invalidFieldException(format("Single child of {0}", OWNER), format("either {0} or {1}", COMPANY, USER));
+		};
+
+	}
+
 	private long toOwnerId(JSONObject owner) {
 		var keys = owner.keySet();
 		if (keys.size() != 1) throw unprocessable("{0} expected to have only one child!",OWNER);