Wildcard file searches

[Rob Bass]

Does anyone know how to do wildcard file searches in Java? For example if the user input in*.java, or *.java ...
Thanks,
Rob

[James Swan]

Check out this thread
http://www.javaranch.com/ubb/Forum38/HTML/000545.html
There is some code for searching down through directories for filename patterns.
James.

[Jim Yingst]

...and if you can use SDK 1.4, it includes a nifty regular expressions package which can make things easier for you.

[Rob Bass]

I wish i could use JDK 1.4 but it's still beta, i looked at the sample code, and I can already do what it is doing, i need to wildcard the searches for files though, I did not see how they were doing that in the example thread.

[James Swan]

Maybe I am missing your point, but doesn't this code do want you are asking (ie. it returns *.txt and *.class files) ?

import java.io.*;
import java.util.*;
public class ListFiles {
    public static void main(String[] args) {
        // eg java ListFiles c:\
        if (args.length > 0) {
            try {
                listFiles(new File(args[0]));
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
    public static void listFiles(File dir) throws Exception {
        File[] files = dir.listFiles();
        for (int i = 0; i < files.length; i++) {
            String fileName = files[i].getName();
            // put in your filter here
            if (fileName.endsWith(".txt") | | fileName.endsWith(".class")) {
                if (files[i].isFile()) {
                    // do whatever you want with the file eg. add to Vector or similar
                    System.out.println(files[i].getPath());
                }
            }
            if (files[i].isDirectory()) {
                listFiles(files[i]);
            }
        }
    }
}

[Jim Yingst]

I assume Rob wants the user to be able to type in something like "foo*.java" and find all files that begin with "foo" and end in ".java". Probably the best plan is to use an existing Java pattern matching library - I believe a lot of folks use OROMatcher. Google "java regular expressions" for others.
Or, you can write your own wildcard matcher if you impose a few restictions to keep it simple - like allow only one * in the string, and no other special characters. Then when the user types "foo*.java", use String indexOf('*') to identify the part before the wildcard ("foo") and the part after (".java"). Then reject any filename that doesn't start with "foo" and end with ".java".

[Rob Bass]

Thanks Jim, exactly right. Sorry I was not clear enough.
Thanks again.
Rob

[Peter den Haan]

Whoa, this thread has a high wheel reinvention index. The way to list filenames conforming to a certain pattern is to instantiate a java.io.FileFilter (or FilenameFilter) and stick it in File.listFiles() and friends.
Unfortunately there's no wildcard-pattern-matching filter implementation, but it's not that hard to roll your own. Especially not if you use Oro or JDK 1.4 regexp.
In a Swing GUI, you'd use a JFileChooser in combination with a javax.swing.filechooser.FileFilter (G-d only knows why this is an object, and why Sun had to invent three slightly different ways to do one and the same thing in the first place).
- Peter
[This message has been edited by Peter den Haan (edited November 08, 2001).]

[Rob Bass]

I have a filenamefilter it filters file extensions but as mentioned I need to do stuff like this rob*.java, but by using the string methods u can probaly do it.

[Jim Yingst]

Peter- sounds familiar. The only piece missing (maybe) is that a "file search" may well mean you need to search through subdirectories as well. Assuming this is the case, we need a recursive method such as what James Swan posted, since listFiles() does not go into subdirectories. Given that you need to iterate through every File in a directory to see if it's another directory, there isn't really a use for FileFilter or its cousins in this case. You can use it anyway, but it doesn't really buy you anything in this case, IMO.

[James Swan]

As Jim pointed out, that's pretty much the motivation behind that piece of code, to be able to recurse through subdirectories, unfortunately you have to hand code a "filename filter".

[Rob Bass]

Thanks again guys, I used ORO, and it rocks!!