support reverse charge

library/src/main/java/org/mustangproject/Product.java

@@ -10,6 +10,8 @@ import java.math.BigDecimal;
 public class Product implements IZUGFeRDExportableProduct {
 	protected String unit, name, description, sellerAssignedID, buyerAssignedID;
 	protected BigDecimal VATPercent;
+	protected boolean isReverseCharge=false;
+	protected boolean isIntraCommunitySupply=false;
 
 	/***
 	 * default constructor
@@ -54,6 +56,37 @@ public class Product implements IZUGFeRDExportableProduct {
 		return this;
 	}
 
+	@Override
+	public boolean isReverseCharge() {
+		return isReverseCharge;
+	}
+
+	@Override
+	public boolean isIntraCommunitySupply() {
+		return isIntraCommunitySupply;
+	}
+
+	/***
+	 * sets reverse charge(=delivery to outside EU)
+	 * @return fluent setter
+	 */
+	public Product setReverseCharge() {
+		isReverseCharge=true;
+		setVATPercent(BigDecimal.ZERO);
+		return this;
+	}
+
+
+	/***
+	 * sets intra community supply(=delivery outside the country inside the EU)
+	 * @return fluent setter
+	 */
+	public Product setIntraCommunitySupply() {
+		isIntraCommunitySupply=true;
+		setVATPercent(BigDecimal.ZERO);
+		return this;
+	}
+
 	@Override
 	public String getUnit() {
 		return unit;

library/src/main/java/org/mustangproject/ZUGFeRD/IZUGFeRDExportableProduct.java

@@ -108,10 +108,16 @@ public interface IZUGFeRDExportableProduct {
 		return false;
 	}
 
+	default boolean isReverseCharge() {
+		return false;
+	}
+
 	default String getTaxCategoryCode() {
 		if (isIntraCommunitySupply()) {
-			return "K";
-		} else if (getVATPercent().equals(new BigDecimal(0))) {
+			return "K"; // within europe
+		} else if (isReverseCharge()) {
+			return "AE"; // to out of europe...
+		} else if (getVATPercent().equals(BigDecimal.ZERO)) {
 			return "Z"; // zero rated goods
 		} else {
 			return "S"; // one of the "standard" rates (not neccessarily a default rate, even a deducted VAT is standard calculation)
@@ -119,8 +125,11 @@ public interface IZUGFeRDExportableProduct {
 	}
 
 	default String getTaxExemptionReason() {
-		if (isIntraCommunitySupply())
+		if (isIntraCommunitySupply()) {
 			return "Intra-community supply";
+		} else if (isReverseCharge()) {
+			return "Reverse Charge";
+		}
 		return null;
 	}
 }