File Exists Wildcard

[Mark Mero]

I have written a piece of code that creates a new file object when passed the full path & filename. It then checks if the file exists. No problem.

File f = new File(location + localname);

if (tj.isReceived()==false){
if (f.exists()){
System.out.println(location + localname + " received.");
//Do other stuff
}

The problem i have is that i want to check if a file exists using a wildcard e.g. check if c:\filex123ABC.txt exists merely by passing C:\file123

Do you have to implement FilenameFilter in order to achieve this & how simple is it to convert the existing code?

Thanks

[Ernest Friedman-Hill]

Hi Mark,

Implementing this as a FilenameFilter would be very easy, something like

class MyFilenameFilter implements FilenameFilter {
  private String _prefix;
  MyFilenameFilter(String prefix) {
    _prefix = prefix;
  }
  public boolean accept(File unused, String name) {
    return name.startsWith(_prefix);
  }
}

You could also easily write one that used regular expressions for matching.

[Mark Mero]

Thanks Ernest,

How would i add this to my existing class.

Regards

[Stan James]

Mark, you'll need to get the directory from your wildcard spec. Something like a substring from 0 to the last position of file separator. Then create a File on that directory and call the list() method with the filter shown above as an argument. All files returned by list() will match your pattern. Cool beans.

BTW: That's all deliberately vague so you can have the thrill of digging through the JavaDoc. Holler if you need more detail.

[Mark Mero]

I have tried the FilelistFilter method, but i want to be able to create a file object without having to list the dir contents. What would the syntax be for creating a file object using regular expressions?

Thanks

[Stan James]

Think you're out of luck. If you created a file with a wildcard in the name what would its name be?

[Mark Mero]

Stan, you're right!
I've modified my use of the FilenameFilter & it is now working fine.

Thanks everyone for all of the assistance.