consider SSC18 when fetching HU's barcode

#280
#269

src/main/java/de/metas/ui/web/handlingunits/HUDocumentView.java

@@ -10,12 +10,11 @@
 import org.compiere.model.I_C_UOM;
 import org.compiere.util.Env;
 
-import com.google.common.base.Preconditions;
-
 import de.metas.adempiere.model.I_M_Product;
 import de.metas.handlingunits.model.I_M_HU;
 import de.metas.handlingunits.model.X_M_HU;
 import de.metas.handlingunits.storage.IHUProductStorage;
+import de.metas.ui.web.exceptions.EntityNotFoundException;
 import de.metas.ui.web.view.ForwardingDocumentView;
 import de.metas.ui.web.view.IDocumentView;
 import de.metas.ui.web.window.datatypes.LookupValue;
@@ -85,6 +84,12 @@ public List<HUDocumentView> getIncludedDocuments()
 		return getIncludedDocuments(HUDocumentView.class);
 	}
 
+	@Override
+	public HUDocumentViewAttributes getAttributes() throws EntityNotFoundException
+	{
+		return HUDocumentViewAttributes.cast(super.getAttributes());
+	}
+
 	/**
 	 *
 	 * @return the ID of the wrapped HU or a value {@code <= 0} if there is none.
@@ -276,23 +281,36 @@ public String getBarcode()
 			return null;
 		}
 
-		// TODO: try fetching SSCC first!
+		//
+		// Try fetching SSCC first!
+		final String sscc18 = getAttributes().getSSCC18().orElse(null);
+		if (sscc18 != null)
+		{
+			return sscc18;
+		}
 
+		//
+		// Use HU's code (i.e. M_HU.Value)
 		final String huCode = getValue();
 		return huCode;
 	}
 
 	public boolean matchesBarcode(final String barcodeToMatch)
 	{
-		Preconditions.checkArgument(barcodeToMatch != null && !barcodeToMatch.isEmpty(), "invalid barcodeToMatch: %s", barcodeToMatch);
+		if (Check.isEmpty(barcodeToMatch, true))
+		{
+			throw new IllegalArgumentException("Invalid barcode: " + barcodeToMatch);
+		}
+
+		final String barcodeToMatchNormalized = barcodeToMatch.trim();
 
 		final String huBarcode = getBarcode();
 		if (huBarcode == null)
 		{
 			return false;
 		}
 
-		return Objects.equals(huBarcode, barcodeToMatch);
+		return Objects.equals(huBarcode, barcodeToMatchNormalized);
 	}
 
 }

src/main/java/de/metas/ui/web/handlingunits/HUDocumentViewAttributes.java

@@ -1,23 +1,28 @@
 package de.metas.ui.web.handlingunits;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import java.util.function.Supplier;
 import java.util.stream.Collectors;
 
 import org.adempiere.mm.attributes.spi.IAttributeValueContext;
 import org.adempiere.mm.attributes.spi.impl.DefaultAttributeValueContext;
+import org.adempiere.util.Check;
 import org.adempiere.util.GuavaCollectors;
+import org.adempiere.util.Services;
 import org.adempiere.util.lang.ExtendedMemorizingSupplier;
 import org.compiere.model.I_M_Attribute;
 import org.compiere.model.X_M_Attribute;
+import org.compiere.util.Env;
 
 import com.google.common.base.MoreObjects;
 
 import de.metas.handlingunits.IHUAware;
 import de.metas.handlingunits.attribute.IAttributeValue;
 import de.metas.handlingunits.attribute.storage.IAttributeStorage;
 import de.metas.handlingunits.attribute.storage.IAttributeStorageListener;
+import de.metas.handlingunits.attributes.sscc18.ISSCC18CodeDAO;
 import de.metas.handlingunits.model.I_M_HU;
 import de.metas.handlingunits.model.X_M_HU;
 import de.metas.ui.web.view.IDocumentViewAttributes;
@@ -63,6 +68,11 @@
 
 /* package */ class HUDocumentViewAttributes implements IDocumentViewAttributes
 {
+	public static final HUDocumentViewAttributes cast(final IDocumentViewAttributes attributes)
+	{
+		return (HUDocumentViewAttributes)attributes;
+	}
+
 	private final DocumentPath documentPath;
 	private final IAttributeStorage attributesStorage;
 
@@ -243,6 +253,22 @@ public LookupValuesList getAttributeDropdown(final String attributeName)
 				.map(itemNP -> LookupValue.fromNamePair(itemNP))
 				.collect(LookupValuesList.collect());
 	}
+
+	public Optional<String> getSSCC18()
+	{
+		final I_M_Attribute sscc18Attribute = Services.get(ISSCC18CodeDAO.class).retrieveSSCC18Attribute(Env.getCtx());
+		if (!attributesStorage.hasAttribute(sscc18Attribute))
+		{
+			return Optional.empty();
+		}
+		final String sscc18 = attributesStorage.getValueAsString(sscc18Attribute);
+		if(Check.isEmpty(sscc18, true))
+		{
+			return Optional.empty();
+		}
+
+		return Optional.of(sscc18.trim());
+	}
 
 	/**
 	 * Intercepts {@link IAttributeStorage} events and forwards them to {@link Execution#getCurrentDocumentChangesCollector()}.