json ignoring some attributes

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

@@ -23,6 +23,7 @@ package org.mustangproject;
 import java.math.BigDecimal;
 import java.util.*;
 
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonInclude;
 import org.mustangproject.ZUGFeRD.*;
 import org.mustangproject.ZUGFeRD.model.DocumentCodeTypeConstants;
@@ -754,6 +755,7 @@ public class Invoice implements IExportableTransaction {
 	 * checks if all required items are set in order to be able to export it
 	 * @return true if all required items are set
 	 */
+	@JsonIgnore
 	public boolean isValid() {
 		return (dueDate != null) && (sender != null) && (sender.getTaxID() != null) && (sender.getVATID() != null) && (recipient != null);
 		//contact

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

@@ -214,11 +214,14 @@ public class Product implements IZUGFeRDExportableProduct {
 		return this;
 	}
 
+	@JsonIgnore
 	@Override
 	public boolean isReverseCharge() {
 		return isReverseCharge;
 	}
 
+
+	@JsonIgnore
 	@Override
 	public boolean isIntraCommunitySupply() {
 		return isIntraCommunitySupply;