[jdjlist] Slow: string += string

[Roger Lacroix]

All:

I have my cells of a table defined as Object[][].  In my program, I added the ability for the user to select rows of the table to copy to the system clipboard (i.e. copy / cut / paste functionality).

Depending on what the user is viewing, there could be 400 rows by 2000 columns.
i.e. Object[][] xx = new Object[400][2000];

Say the user selects 20 rows, then I need to combine 40000 cells (20 * 2000).  I have done every trick that I can think of, but it still is not as fast as I would expect.  Right now I combine each row into a string then I combine each row-string each the final string.

Here is my current code:

   String[] rowData = new String[selected.length];    
   for (int r = 0; r < selected.length; r++)          
   {                                                  
      ptr = selected[r];                              
                                                      
      rowData[r] = msgCells[ptr][1].toString();       
      for(int c = 2; c < endColumn; c++)              
      {                                               
         if (msgCells[ptr][c] != null)                
         {                                            
            rowData[r] += msgCells[ptr][c].toString();
         }                                            
      }                                               
   }                                                  
                                                      
   for (int r = 0; r < selected.length; r++)          
   {                                                  
      tempClipboard += rowData[r];                    
   }                                                  

Does anyone out there in Java land have a tip / trick /snippet of code to quickly & efficiently combine a large number of objects into a SINGLE string.

Thanks to all.

later
Roger Lacroix
Enterprise Architect
Capitalware Inc.
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