Around an hour of manual javadoc documentation (why don't I just use chatGPT for that?)

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

@@ -14,12 +14,33 @@ import java.math.BigDecimal;
 
 @JsonIgnoreProperties(ignoreUnknown = true)
 @JsonInclude(JsonInclude.Include.NON_EMPTY)
+/***
+ * This is the invoice but with redundant information, i.e. total amount etc.
+ * It has a calculate function which overwrites this total amount but fundamentally
+ * it's useful e.g. for imported invoices, because they may have diverging
+ * amounts, and some users are interested in retrieving the original ones
+ */
 public class CalculatedInvoice extends Invoice implements Serializable {
 
+	/***
+	 * de factor the total net amount
+	 */
 	protected BigDecimal lineTotalAmount=null;
+	/**
+	 * still to be paid
+	 */
 	protected BigDecimal duePayable=null;
+	/**
+	 * originally to be paid (without prepayments)
+	 */
 	protected BigDecimal grandTotal=null;
+	/**
+	 * the net amount upon which value added taxes are applied
+	 */
 	protected BigDecimal taxBasis=null;
+	/**
+	 * the total sum of value added taxes
+	 */
 	protected BigDecimal VATtotal=null;
 	protected TransactionCalculator tc=null;
 

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

@@ -23,6 +23,9 @@ public class CashDiscount implements IZUGFeRDCashDiscount {
 	 */
 	protected Integer days;
 
+	/**
+	 * The original payment amount
+	 */
 	protected BigDecimal basisAmount;
 
 	/***
@@ -45,6 +48,10 @@ public class CashDiscount implements IZUGFeRDCashDiscount {
 
 	}
 
+	/***
+	 * how much this discount removed from the original dept
+	 * @return the percent
+	 */
 	public BigDecimal getPercent() {
 		return percent;
 	}
@@ -54,6 +61,10 @@ public class CashDiscount implements IZUGFeRDCashDiscount {
 		return this;
 	}
 
+	/***
+	 * get the number of calendar days this cash discount is valid
+	 * @return the number (integer) of days
+	 */
 	public Integer getDays() {
 		return days;
 	}

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

@@ -67,6 +67,11 @@ public class DirectDebit implements IZUGFeRDTradeSettlementDebit {
 		return this.IBAN;
 	}
 
+	/***
+	 * sets the IBAN id (not neccessarily the IBAN, can be anonymized) of the
+	 * @param iBAN the IBAN id (not neccessarily the IBAN, can be anonymized) where the money is deducated
+	 * @return fluent setter
+	 */
 	public DirectDebit setIBAN(String iBAN) {
 		this.IBAN = iBAN;
 		return this;

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

@@ -1,6 +1,35 @@
 package org.mustangproject;
 
 public enum EStandard {
-	facturx, orderx, despatchadvice, ubldespatchadvice, zugferd, cii, ubl, ubl_creditnote
+	/**factur-x/zugferd 2*/
+	facturx,
+	/***
+	 * order-x
+	 */
+	orderx,
+	/***
+	 * deliver-x
+	 */
+	despatchadvice,
+	/***
+	 * 1lieferschein
+	 */
+	ubldespatchadvice,
+	/***
+	 * ZUGFeRD 1
+	 */
+	zugferd,
+	/***
+	 * imported from cross industry invoice
+	 */
+	cii,
+	/***
+	 * imported from an UBL invoice
+	 */
+	ubl,
+	/***
+	 * imported from an UBL credit note
+	 */
+	ubl_creditnote
 
 }

library/src/main/java/org/mustangproject/Exceptions/ArithmeticException.java

@@ -3,14 +3,20 @@ package org.mustangproject.Exceptions;
 import java.text.ParseException;
 
 /***
- * will be thrown if an invoice cant be reproduced numerically
  * ArithmetricException for backwards compatibility, was a spelling error
  */
 public class ArithmeticException extends ArithmetricException {
+	/***
+	 *  will be thrown if an invoice cant be reproduced numerically
+	 */
 	public ArithmeticException() {
 		super();
 	}
 
+	/***
+	 * Exceptions usually are raised with details
+	 * @param details the text
+	 */
 	public ArithmeticException(String details) {
 		super(details);
 	}

library/src/main/java/org/mustangproject/Exceptions/ArithmetricException.java

@@ -3,14 +3,21 @@ package org.mustangproject.Exceptions;
 import java.text.ParseException;
 
 /***
- * will be thrown if an invoice cant be reproduced numerically
+ *
  * (deprecated, because of typo)
  */
 public class ArithmetricException extends ParseException {
+	/***
+	 * will be thrown if an invoice cant be reproduced numerically
+	 */
 	public ArithmetricException() {
 		this("");
 	}
 
+	/***
+	 * Telling the issue...
+	 * @param details explanation details
+	 */
 	public ArithmetricException(String details) {
 		super("Could not reproduce the invoice. " + details, 0);
 	}

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

@@ -173,15 +173,20 @@ public class Invoice implements IExportableTransaction {
 
 	/***
 	 * BT-17
-	 * @param dr
+	 * @param dr the Referenced Document (may contain ID, typecode, date...)
-	 * @return
+	 * @return fluent setter
 	 */
 	public Invoice setTenderReferencedDocument(ReferencedDocument dr) {
 		dr.setTypeCode("50");//50 is fixed for tender documents
 		tenderReference=dr;
 		return this;
 	}
-	
+
+	/***
+	 * Sets a reference to a tender
+	 * @param ID the key ID of the tender
+	 * @return fluent setter
+	 */
 	public Invoice setTenderReferencedDocument(String ID) {
 		ReferencedDocument dr=new ReferencedDocument(ID);
 		setTenderReferencedDocument(dr);
@@ -192,6 +197,9 @@ public class Invoice implements IExportableTransaction {
 
 	/** BT-18 */
 	@Override
+	/***
+	 *
+	 */
 	public IReferencedDocument getObjectIdentifierReferencedDocument() {
 		return objectIdentifierReference;
 	}

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

@@ -23,6 +23,9 @@ import java.nio.charset.StandardCharsets;
 public class CustomXMLProvider implements IXMLProvider {
 
 	protected byte[] zugferdData;
+	/***
+	 * the scope=profile this XML data is provided in
+	 */
 	protected Profile profile=Profiles.getByName("EN16931");
 
 	@Override

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

@@ -32,6 +32,9 @@ import org.mustangproject.FileAttachment;
 import org.mustangproject.Invoice;
 import org.mustangproject.XMLTools;
 
+/***
+ *
+ */
 public class DAPullProvider extends ZUGFeRD2PullProvider {
 
 	protected IExportableTransaction trans;

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

@@ -66,7 +66,24 @@ public interface IZUGFeRDExporter extends Closeable, IExporter  {
 	public String getNamespaceForVersion(int ver);
 	public String getPrefixForVersion(int ver) ;
 	public IZUGFeRDExporter disableAutoClose(boolean disableAutoClose);
+
+	/***
+	 * attach an additional PDF file attachment for Factur-X attachments
+	 * (for attached files embedded into XML, within Germany domestically preferred,
+	 * please refer to @see Invoice.embedFileInXML)
+	 * @param file mime type and data
+	 */
 	public void attachFile(FileAttachment file);
+	/***
+	 * attach an additional PDF file attachment for Factur-X attachments
+	 * (for attached files embedded into XML, within Germany domestically preferred,
+	 * please refer to @see Invoice.embedFileInXML
+	 *
+	 * @param filename the filename to be suggested
+	 * @param data the binary data
+	 * @param mimetype the mime type, from the list of allowed mime types
+	 * @param relation the PDF relation
+	 */
 	public void attachFile(String filename, byte[] data, String mimetype, String relation);
 	public IXMLProvider getProvider();
 

library/src/main/java/org/mustangproject/ZUGFeRD/model/DateTimeTypeConstants.java

@@ -19,6 +19,9 @@
 package org.mustangproject.ZUGFeRD.model;
 
 public class DateTimeTypeConstants {
+	/***
+	 * the id of the yyyymmdd - Date format
+	 */
 	public static final String DATE = "102";
 	public static final String MONTH = "610";
 	public static final String WEEK = "616";

library/src/main/java/org/mustangproject/ZUGFeRD/model/DocumentCodeTypeConstants.java

@@ -19,9 +19,19 @@
 package org.mustangproject.ZUGFeRD.model;
 
 public class DocumentCodeTypeConstants {
+	/***
+	 * default invoice typecode
+	 */
 	public static final String INVOICE = "380";
+	/***
+	 * typecode of a credit note, with reference to an invoice.
+	 * Used in all(?) non-german legislations like france to correct a invoice
+	 */
 	public static final String CREDITNOTE = "381";
 	public static final String DEBITNOTE = "84";
+	/***
+	 * typecode for a german corrective invoice (negative qtys)
+	 */
 	public static final String CORRECTEDINVOICE = "384";
 	public static final String SELFBILLING = "389";
 	public static final String PARTIAL_BILLING = "326";

library/src/main/java/org/mustangproject/ZUGFeRD/model/DocumentContextParameterTypeConstants.java

@@ -19,7 +19,16 @@
 package org.mustangproject.ZUGFeRD.model;
 
 public class DocumentContextParameterTypeConstants {
+	/***
+	 * the URN of the guideline ID of a ZUGFeRD 1 basic profile
+	 */
 	public static final String BASIC = "urn:ferd:CrossIndustryDocument:invoice:1p0:basic";
+	/***
+	 * the URN of the guideline ID of a ZUGFeRD 1 comfort profile
+	 */
 	public static final String COMFORT = "urn:ferd:CrossIndustryDocument:invoice:1p0:comfort";
+	/***
+	 * the URN of the guideline ID of a ZUGFeRD 1 extended profile
+	 */
 	public static final String EXTENDED = "urn:ferd:CrossIndustryDocument:invoice:1p0:extended";
 }

library/src/main/java/org/mustangproject/util/ByteArraySearcher.java

@@ -1,5 +1,8 @@
 package org.mustangproject.util;
 
+/**
+ * Find string in large files, text, binary or binary (PDF)
+ */
 public final class ByteArraySearcher {
 
 	private ByteArraySearcher() {
@@ -31,10 +34,22 @@ public final class ByteArraySearcher {
 		return -1;
 	}
 
+	/***
+	 * check if a string or any substring of haystack matches (case sensitive) needle
+	 * @param haystack
+	 * @param needle
+	 * @return true, if haystack contains needle
+	 */
 	public static boolean contains(byte[] haystack, byte[] needle) {
 		return indexOf(haystack, needle) >= 0;
 	}
 
+	/***
+	 * check if haystack starts with (case sensitive) needle
+	 * @param haystack
+	 * @param needle
+	 * @return true, if haystack immediately starts with needle
+	 */
 	public static boolean startsWith(byte[] haystack, byte[] needle) {
 		if (needle.length > haystack.length) {
 			return false;