Taking too much time using BufferedWriter to write to a file

Question

Hi,
I'm using the method extractItems() which is given below to write data to a file. This method is taking too much time to execute when the number of records in the enumeration is 10000 and above. To be precise it takes around 70 minutes. The writing pauses intermittently for 20 seconds after writing a few lines and sometimes for much more. Has somebody faced this problem before and if so what could be the problem. This is a very high priority work and it would be really helpful if someone could give me some info on this.
Thanks in advance.
public String extractItems() throws InternalServerException{
try{
               String extractFileName = getExtractFileName();
               FileWriter fileWriter = new FileWriter(extractFileName);
               BufferedWriter bufferWrt = new BufferedWriter(fileWriter);
               CXBusinessClassIfc editClass = new ExploreClassImpl(className, mdlMgr );
System.out.println("Before -1");
               CXPropertyInfoIfc[] propInfo = editClass.getClassPropertyInfo(configName);
System.out.println("After -1");
          PrintWriter out = new PrintWriter(bufferWrt);
System.out.println("Before -2");
          TemplateHeaderInfo.printHeaderInfo(propInfo, out, mdlMgr);
System.out.println("After -2");
XDItemSet itemSet = getItemsForObjectIds(catalogEditDO.getSelectedItems());
Enumeration allitems = itemSet.allItems();
System.out.println("the batch size : " +itemSet.getBatchSize());
XDForm frm = itemSet.getXDForm();
XDFormProperty[] props = frm.getXDFormProperties();
System.out.println("Before -3");
bufferWrt.newLine();
long startTime ,startTime1 ,startTime2 ,startTime3;
startTime = System.currentTimeMillis();
System.out.println("time here is--before-while : " +startTime);
while(allitems.hasMoreElements()){
String aRow = "";
XDItem item = (XDItem)allitems.nextElement();
for(int i =0 ; i < props.length; i++){
     String value = item.getStringValue(props);
     if(value == null || value.equalsIgnoreCase("null"))
          value = "";
                         if(i == 0)
                              aRow = value;
                         else
                              aRow += ("\t" + value);
startTime1 = System.currentTimeMillis();
System.out.println("time here is--before-writing to buffer --new: " +startTime1);
bufferWrt.write(aRow.toCharArray());
bufferWrt.flush();//added by rosmon to check extra time taken for extraction//
bufferWrt.newLine();
startTime2 = System.currentTimeMillis();
System.out.println("time here is--after-writing to buffer : " +startTime2);
startTime3 = System.currentTimeMillis();
System.out.println("time here is--after-while : " +startTime3);
               out.close();//added by rosmon to check extra time taken for extraction//
bufferWrt.close();
fileWriter.close();
System.out.println("After -3");
return extractFileName;
catch(Exception e){
               e.printStackTrace();
throw new InternalServerException(e.getMessage());

Answer 1

Hi fiontan,
Thanks a lot for the response!!!
Yeah!! I kow it's a lotta code, but i thought it'd be more informative if the whole function was quoted.
I'm in fact using the PrintWriter to wrap the BufferedWriter but am not using the print() method.
Does it save any time by using the print() method??
The place where the delay is occurring is the wile loop shown below:
            while(allitems.hasMoreElements()){
            String aRow = "";
                XDItem item = (XDItem)allitems.nextElement();
                for(int i =0 ; i < props.length; i++){
                     String value = item.getStringValue(props);
     if(value == null || value.equalsIgnoreCase("null"))
          value = "";
                         if(i == 0)
                              aRow = value;
                         else
                              aRow += ("\t" + value);
startTime1 = System.currentTimeMillis();
System.out.println("time here is--before-writing to buffer --out.flush() done: " +startTime1);
bufferWrt.write(aRow.toCharArray());
out.flush();//added by rosmon to check extra time taken for extraction//
bufferWrt.flush();//added by rosmon to check extra time taken for extraction//
bufferWrt.newLine();
startTime2 = System.currentTimeMillis();
System.out.println("time here is--after-writing to buffer : " +startTime2);
What exactly happens is that after a few loops it just seems to sleep for around 20 seconds and then again starts off and ............it goes on till the records are done.
Please do lemme know if you have any idea as to why this is happening !!!!! This bug is giving me the scare.
thanks in advance