Error in Duplicate file Handling

Question

Hi All,
      We want to avoid duplicate files in XI for that we used below code in  UDF in mapping
try{
String processedFileDatabase = processedFile[0];
String sourceFileName;
DynamicConfiguration attrib = (DynamicConfiguration)container.getTransformationParameters().get(StreamTransformationConstants.DYNAMIC_CONFIGURATION);
DynamicConfigurationKey fileKey = DynamicConfigurationKey.create("http:/"+"/sap.com/xi/XI/System/File","FileName");
attrib.put(fileKey,attrib.get(fileKey));
sourceFileName = attrib.get(fileKey);
File fileDB=new File(processedFileDatabase);
if (!(fileDB.exists() && fileDB.canWrite() && fileDB.canRead())){
fileDB.createNewFile();
Vector fileNameList = new Vector();
BufferedReader br = null;
br = new BufferedReader(new FileReader(processedFileDatabase));
String name = new String();
//loop and read a line from the file as long as we dont get null
while ((name = br.readLine()) != null)
//add the read word to the wordList
fileNameList.add(name);
br.close();
boolean fileAlreadyProcessed = fileNameList.contains(sourceFileName);
if (!fileAlreadyProcessed) {
Writer output = new BufferedWriter(new FileWriter(new File(processedFileDatabase),true));
output.write(sourceFileName + "\r\n");
output.flush();
output.close();
result.addValue("" + !fileAlreadyProcessed);
}catch(java.io.IOException e){
            e.printStackTrace();
But this is not working ..its unable to Map....
Plz help us in this regard,

Answer 1

The file name is not going to fileDB and hence it is unable to create the target element.
I followed the below link solution 2
http://wiki.sdn.sap.com/wiki/display/XI/DifferentwaystokeepyourInterfacefromprocessingduplicate+files
I seen that fileDB file is empty ,