[jdjlist] RE: Slow: string += string

[Allan Wick]

Use a StringBuffer.

 

StringBuffer theBuffer = StringBuffer();

 

   for (int r = 0; r < selected.length; r++)          
   {                                                  

            theBuffer.append( rowdata[r] );

        }

 

String output = theBuffer.toString();

 

Something like that...

 

-Al Wick

-----Original Message-----
From: Roger Lacroix [mailto:[EMAIL PROTECTED]]
Sent: Sunday, January 19, 2003 5:20 PM
To: JDJList
Subject: [jdjlist] Slow: string += string

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.
____________________________________________________
To change your JDJList options, please visit:
http://www.sys-con.com/java/list.cfm

Be respectful! Clean up your posts before replying
____________________________________________________

____________________________________________________
To change your JDJList options, please visit:
http://www.sys-con.com/java/list.cfm

Be respectful! Clean up your posts before replying
____________________________________________________