Mapping issue - Remove Duplicates

Question

Hello,
I want to remove the duplicate nodes. Below is the issue:
Input Structure:
MainNode   0..n
--SubNode  0..n
key
Val
Output Structure:
MainNode 0..n
--Subnode 0..n
key
Val
Now the example input:
<MainNode>
<subnode>
<key> 1001 </key>
<val< 1 </Val>
</Subnode>
<subnode>
<key> 1002 </key>
<val> 2 </val>
</subnode>
<subnode>
<key> 1001 </key>
<val> 1 </val>
</subnode>
Output should be:
<MainNode>
<Subnode>
<key> 1001 </key>
<val> 1 </val>
</subnode>
<subnode>
<key> 1002 </key>
<val> 2 </val>
</subnode>
i.e., it should remove the duplicate keys.
I tried as below, but doesnot work:
key --> removeContext --> Merge userdefinded function -->Subnode
Merge:
public void merge(String[] key, ResultList result, Container container) {
HashSet hs = new HashSet();
for(int i = 0; i < a.length; i++) {
    hs.add(a<i>);       
Iterator it = hs.iterator();
while(it.hasNext()) {
    String val = it.next().toString();
    result.addValue(val);
    result.addContextChange();
Any other solution?

Answer 1

Hi laxmi,
  First try to sort those values by Key using Sort and collapse context so that when sorted all the similar elments group together then apply collapse context so that only the first repetition (1001) will be considered .Then use split by value (on change) and map .Try to think to do using predefined function SORT.
http://help.sap.com/saphelp_nw04/helpdata/en/43/c4cdfc334824478090739c04c4a249/content.htm
Thanks,
Ram.