String replace (first occurence)

Question

Hi:
I have a input file that contains the following -
set var=
set var=%2
Now, I need to replace the first occurence of set var= with set var=value, so ouptut file should look like
set var=value
set var=%2
Apparently my code seems to change all occurences of set var= inspite of using replaceFirst, can you please point out what I am missing?
while((varLine = InputFile.readLine()) != null)
                 if(varLine.endsWith("="))
              new_varLine = varLine.replaceFirst(find_string,replacement_string);
             OutputFile.write(var_envLine);
                 OutputFile.write("\n");
            }

Answer 1

uncle_alice wrote:
Just set a flag when you've done the replacement: boolean didIt = false;Or a sequential program, which can be clearer than adding conditional logic in loops.
while((varLine = inputFile.readLine()) != null && ! varLine.matches("\\s*set\\s+var\\s*=\\s*"))  {
   outputFile.write(varLine);
   outputFile.write("\n");
if (varLine == null) return;
outputFile.write(varLine + replacement_string);
outputFile.write("\n");
while((varLine = inputFile.readLine()) != null) {
   outputFile.write(varLine);
   outputFile.write("\n");
{code}
IME in debugging more complicated code the less state you have to think about when working out what the computer should be doing at any part of the code, the better. Most flags can be converted to breaks, continues or method calls; finally lets you clean up on early returns.