Java: do something if regex not found

Question

I'm parsing log files, and need to do one thing when a regex is found (add ',TRUE' to a variable, .csv, ArrayList), and something else (add an empty slot, "," or ",_" if an empty slot isn't good) when that regex is not found.

There can be 1-~200 entries being parsed from each log file - so the regex could match none-to-several times.

I've tried several options, either get an error on compile (not liking testing a Boolean against a string), no observable action occurs, or when the regex is found I get the result for when regex not found.

I need the output in a variable, .csv or an ArrayList, so if a match is not found, then I need an empty ',' because the output is a pre-defined table, so the columns need to align properly.

Combos I've tried:

if(!noBaseText.equals("No matching base data found"))
if(!noBaseText.equals("No matching base data found") == false)
if(noBaseText.equals("No matching base data found" != true))
if(noBaseText.isEmpty())
if(noBaseText.equals(""))
if(!noBaseText.equals(""))
if(noBaseText.equals("No matching base data found"))

'} else {' and '} else if (...) {' with the combos above, both when a nested if/else (as in code below) or as an 'else' to the 'if (baseMatcher.find())' return identical results.

Code Snippet:

Pattern noBase = Pattern.compile("(?<noBase>No matching base data found)");
try(corrReader)
            {
                while ((corrLine = corrReader.readLine())!=null)
                {
                    corrText = corrLine.trim();
                    Matcher baseMatcher = noBase.matcher(corrText);
                    if (baseMatcher.find()) 
                    {
                        String noBaseText = baseMatcher.group("noBase");
                        if(!noBaseText.equals("No matching base data found"))
                        {
                            corrOutput += ",";
                        } else if(noBaseText.equals("No matching base data found")) {
                            corrOutput += ",TRUE";
                        } //end else
                    } //end if(baseMatcher)
                } //end while(corrLine)
            } //end try(corrReader)

The output I'm getting when there is a match:

AA-123-12345-SP1.SSF,TRUE,

The output I'm getting when there isn't a match:

AA-123-12345-SP2.SSF,100,100,guug04314054.zip,

The output I need to get when there isn't a match:

AA-123-12345-SP2.SSF,,100,100,guug04314054.zip,

When the regex matches, and ',TRUE' is returned, there will be no following entries; when the regex does not match and a ',' is returned, there will be additional entries.

Answer 1

You can use the ternary operator to accomplish this:

boolean found = false;
while ((corrLine = corrReader.readLine())!=null)
{
  ...
      String noBaseText = baseMatcher.group("noBase");
      found |= noBaseText.equals("No matching base data found");
  ...
}

corrOutput += found ? "TRUE," :  ",";

If the found evaluates to true, you'll get "TRUE," otherwise "," .

Answer 2

I am not sure if I got this right, but.. if you want to check if pattern is empty, do the following:

if(noBase.pattern().isEmpty()) {
// do your stuff
}