Sum quantities in message mapping

Question

Hello there.
I'm trying to map a xml message with items (material/quantity) into another one with exact same structure but collecting the lines by material.
The XML's structure is like:
header_fields ...
<items>
  <item>
    <matnr>1</matnr>
    <qty>1</qty>
  </item>
  <item>
    <matnr>2</matnr>
    <qty>10</qty>
  </item>
<item>
    <matnr>1</matnr>
    <qty>5</qty>
  </item>
</items>
When mapping <item> tag, I used a user-defined function Like this:
public void addMaterial(String[] material,ResultList result,Container container){
Vector vMats = new Vector();
for (int i = 0; i < material.length; i++ ){
   if (!vMats.contains(material<i>)){
      vMats.addElement(material<i>);
for (int i = 0; i < vMats.size()-1; i++){
     result.addValue("");
This is working well (I think) because i only get different materials in output queque in mapping.
Now, I want to actually calculate quantities, mapping qty tag, collected by material, and i'm trying something like:
public void sumQuantities(String[] material,String[] units,ResultList result,Container container){
Vector vMats = new Vector();
Vector vQuant = new Vector();
for (int i = 0; i < material.length; i++ ){
   if (!vMats.contains(material<i>)){
      vMats.addElement(material<i>);
      vQuant.addElement(units<i>);
  else {
for (int i = 0; i < vQuant.size()-1; i++){
     result.addValue("");
I'm creating a vector vMats to have an array with not repeated material, and a vQuant array to sum quantities. There is the ???? part ...
I'm sorry for the SIMPLE question but i'm an abaper trying a bit in the java workd
The needed result is:
header_fields ...
<items>
  <item>
    <matnr>1</matnr>
    <qty>6</qty>
  </item>
  <item>
    <matnr>2</matnr>
    <qty>10</qty>
  </item>
</items>
Regards,
Valter Oliveira.

Answer 1

Hello VJ.
Thanks for your input. There were some problems in the type convertion in your code, but using your idea with small changes found in java foruns I got one of the possible solutions (probably not the best one). I've tryied it with several complex combinations and so far so good ... always got what we need.
The code for the 3 UDF's that I created is:
For <Item> (non-repeated materials)
public void additem(String[] material,ResultList result,Container container){
Vector vMats = new Vector();
for (int i = 0; i < material.length; i++ ){
   if (!vMats.contains(material<i>)){
      vMats.addElement(material<i>);
      result.addValue("X");
For <matnr> (non-repeated materials)
public void addmaterial(String[] material,ResultList result,Container container){
Vector vMats = new Vector();
for (int i = 0; i < material.length; i++ ){
   if (!vMats.contains(material<i>)){
      vMats.addElement(material<i>);
      result.addValue(material<i>);
For <qty> (collected by material)
public void sumQuantities(String[] material,String[] units,ResultList result,Container container){
Vector vMats = new Vector();
Vector vQty = new Vector();
for (int i = 0; i < material.length; i++ ){
   if (!vMats.contains(material<i>)){
              vMats.addElement(material<i>);
              vQty.addElement(units<i>);
  else {
              int p = vMats.indexOf(material<i>);
              int actual = Integer.parseInt(units<i>);
              String[] aux = (String[])vQty.toArray(new String[vQty.size()]);
              int previous = Integer.parseInt(aux[p]);
              int sum = actual + previous;
              String strsum = Integer.toString(sum);
              vQty.set(p, strsum);
String[] end = (String[])vQty.toArray(new String[vQty.size()]);
for (int i = 0; i < vQty.size(); i++){
     result.addValue(end<i>);
After the UDF's, to achieve <matnr> and <qty> in output XML, I had to use SPLIT by VALUE.
I'll keep this open for a while to see if anyone has a better solution.
Regards,
Valter Oliveira