5823-app - Delivery contract with same product but different attributes

* Port thw complete method IFlatrateBL.isAllowedToOverlapWithOtherTerms to this branch
* FlatrateBL allow contract with type TYPE_CONDITIONS_Procurement to overlap
* Add a bit of javadoc to explain the issue
#5823

(cherry picked from commit 2e37119)

solved Conflicts:
	de.metas.contracts/src/main/java/de/metas/contracts/IFlatrateBL.java
	de.metas.contracts/src/main/java/de/metas/contracts/impl/FlatrateBL.java

de.metas.contracts/src/main/java/de/metas/contracts/IFlatrateBL.java

@@ -198,11 +198,21 @@ I_C_Flatrate_Term createTerm(IContextAware context,
 	void voidIt(I_C_Flatrate_Term term);
 
 	/**
-	 * Check if there are terms for the same that have a time period overlapping with the given term and match with the same product or product category.
+	 * Return {@code true} if the given term (by virtue of its conditions-type) does not define a set of invoice candidates that "belong" to it.
+	 * Examples for ICs that belong to a contract in this sense are e.g. ICs that shall trigger a refund, a commission payment or are empties (e.g. empty pallets).
+	 * In all this cases, a completed term matches a set of ICs and for every given ICs, we need to make sure that max. one term matches it.
 	 *
+	 * Also see {@link #hasOverlappingTerms(I_C_Flatrate_Term)}.
+	 */
+	boolean isAllowedToOverlapWithOtherTerms(I_C_Flatrate_Term term);
+
+	/**
+	 * Check if there are terms for the same bPartner that have a time period overlapping with the given term and match with the same product or product category.
+	 * <p>
+	 * Note that overlapping need to be prevented for those types of terms (like refund contracts or refundable contracts) to which newly created invoice candidates need to be mapped.
+	 * Overlapping is no problem for subscription contracts.
 	 *
-	 * @param term
-	 * @return
+	 * Also see {@link #isAllowedToOverlapWithOtherTerms(I_C_Flatrate_Term)}.
 	 */
 	boolean hasOverlappingTerms(final I_C_Flatrate_Term term);
 

de.metas.contracts/src/main/java/de/metas/contracts/IFlatrateDAO.java

@@ -155,7 +155,7 @@ public interface IFlatrateDAO extends ISingletonService
 	void updateQtyActualFromDataEntry(I_C_Flatrate_DataEntry dataEntry);
 
 	/**
-	 * Retrieves the flatrate term matching the given invoice candidate or <code>null</code>.<br>
+	 * Retrieves the flatrate term matching the given invoice candidate (or {@code code>}) by using {@link I_C_Flatrate_Matching} Records.<br>
 	 * Basically calls {@link #retrieveTerms(Properties, int, Timestamp, int, int, int, String)}, but discards all terms that have <code>IsSimulation=Y</code>.
 	 *
 	 * @return the term or <code>null</code>

de.metas.contracts/src/main/java/de/metas/contracts/impl/FlatrateBL.java

@@ -1553,17 +1553,19 @@ public void complete(final I_C_Flatrate_Term term)
 	@Override
 	public void completeIfValid(final I_C_Flatrate_Term term)
 	{
-		final boolean hasOverlappingTerms = hasOverlappingTerms(term);
-		if (hasOverlappingTerms)
+		if (!isAllowedToOverlapWithOtherTerms(term))
 		{
+			final boolean hasOverlappingTerms = hasOverlappingTerms(term);
+			if (hasOverlappingTerms)
+			{
 
-			Loggables.get().addLog(Services.get(IMsgBL.class).getMsg(
-					Env.getCtx(),
-					MSG_HasOverlapping_Term,
-					new Object[] { term.getC_Flatrate_Term_ID(), term.getBill_BPartner().getValue() }));
-			return;
+				Loggables.get().addLog(Services.get(IMsgBL.class).getMsg(
+						Env.getCtx(),
+						MSG_HasOverlapping_Term,
+						new Object[] { term.getC_Flatrate_Term_ID(), term.getBill_BPartner().getValue() }));
+				return;
+			}
 		}
-
 		complete(term);
 	}
 
@@ -1575,6 +1577,18 @@ public void voidIt(final I_C_Flatrate_Term term)
 
 	}
 
+	@Override
+	public boolean isAllowedToOverlapWithOtherTerms(@NonNull final I_C_Flatrate_Term term)
+	{
+		final String typeConditions = term.getType_Conditions();
+
+		// These contract types do not match "other" ICs such as ICs that trigger a commission, or IC that belong to a vendor's empty package (pallette/TU).
+		// Therefore they can overlap without causing us any problems.
+		final boolean allowedToOverlapWithOtherTerms = X_C_Flatrate_Term.TYPE_CONDITIONS_Subscription.equals(typeConditions)
+				|| X_C_Flatrate_Term.TYPE_CONDITIONS_Procurement.equals(typeConditions);
+		return allowedToOverlapWithOtherTerms;
+	}
+
 	@Override
 	public boolean hasOverlappingTerms(final I_C_Flatrate_Term newTerm)
 	{

de.metas.contracts/src/main/java/de/metas/contracts/interceptor/C_Flatrate_Term.java

@@ -493,6 +493,10 @@ public void preventOverlappingTerms_OnComplete(final I_C_Flatrate_Term term)
 		// services
 		final IFlatrateBL flatrateBL = Services.get(IFlatrateBL.class);
 
+		if (flatrateBL.isAllowedToOverlapWithOtherTerms(term))
+		{
+			return;
+		}
 		final boolean hasOverlappingTerms = flatrateBL.hasOverlappingTerms(term);
 		if (hasOverlappingTerms)
 		{
@@ -518,7 +522,7 @@ private void setMasterEndDate(final I_C_Flatrate_Term term)
 
 		term.setMasterEndDate(masterEndDate);
 	}
-	
+
 	private Timestamp computeMasterEndDateIfC_FlatrateTerm_Next_IDChanged(@NonNull final I_C_Flatrate_Term term, Timestamp masterEndDate)
 	{
 		if (InterfaceWrapperHelper.isValueChanged(term, I_C_Flatrate_Term.COLUMNNAME_C_FlatrateTerm_Next_ID) && !term.isAutoRenew())
@@ -532,7 +536,7 @@ private Timestamp computeMasterEndDateIfC_FlatrateTerm_Next_IDChanged(@NonNull f
 				masterEndDate = term.getEndDate();
 			}
 		}
-		
+
 		return masterEndDate;
 	}
 }