Regex and implementing FilenameFilter problem

Question

Hello,
So what I'm trying to do is to create a program that takes a certain set of files, pulls the first line of each file and uses it to name the file. Right now, I'm at the point of getting a listing of files based on a patterns. So when I run the program on the command line (of a windows machine), it spit out the files that I'm looking for. Something like:
java FileRenamer *.txt
Above should produce a listing of only files that have .txt on them (I want to have the capability to choose *.txt or whatever other combination of pattern match).
To do the above, I want to use a FileNameFilter interface to figure out what files match. The problem that I'm running into is that when I run a unit test against the getFilesListBasedOnPattern method, I get:
java.util.regex.PatternSyntaxException: Dangling meta character '*' near index 0
*.txt
The problem is that the *.txt has a regex character (the *) and I'm not sure how make it behave like the wildcard in the dos command line where *.txt means everything that has .txt at the end.
The code listing is below. Does anyone have any suggestions on how to best approach this?
mapsmaps
=======> Code below <=======
// unit test snippet that causes blow out:
FileRenamer fr = new FileRenamer();
String [] strArrFilesBasePattern = fr.getFilesListBasedOnPattern(dirTestFiles,"*.txt");
====
//main program
package com.foo.filerenamer;
import java.io.File;
import java.io.FilenameFilter;
import java.util.Vector;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
* TODO Use regexp to filter out input to *.txt type of thing or nothing else
public class FileRenamer
    // Vallid file patterns are *.*, ?
    public static final String strVALIDINPUTCHARS = "[_.a-zA-Z0-9\\s\\*\\?-]+";
    private static Pattern regexPattern = Pattern.compile(strVALIDINPUTCHARS);
    private static Matcher regexMatcher;
     * @param args
     * @throws InterruptedException
    public static void main(String[] args) throws InterruptedException
        int intMillis = 0;
        if (args.length > 0)
            try
                intMillis = Integer.parseInt(args[0]);
                System.out.println("Sleep set to " + intMillis + " seconds");
            catch (NumberFormatException e)
                intMillis = 5000;
                System.out.println("Sleep set to default of " + intMillis + " since first parameter was non-int");
            for (int i=0;i<args.length;i++)
                System.out.println("hello there - args["+i+"] = "+ args);
Thread.sleep(intMillis);
// TODO Auto-generated method stub
public boolean checkArgs(String [] p_strAr)
boolean bRet = false;
if (p_strAr.length != 1)
return false;
else
regexMatcher = regexPattern.matcher(p_strAr[0]);
bRet = regexMatcher.matches();
return bRet;
public String[] getFilesListBasedOnPattern(File p_dirFilesLoc, String p_strValidPattern)
String[] strArrFilteredFileNames = p_dirFilesLoc.list(new RegExpFileFilter(p_strValidPattern));
return strArrFilteredFileNames;
class RegExpFileFilter implements FilenameFilter
private String m_strPattern = null;
private Pattern m_regexPattern;
public RegExpFileFilter(String p_strPattern)
m_strPattern = p_strPattern;
m_regexPattern = Pattern.compile(m_strPattern);
public boolean accept(File m_directory, String m_filename)
if (m_regexPattern.matcher(m_filename).matches())
return true;
return false;

Answer 1

I am doing something similar but have a problem with Java automatically converting wildcards in path-arguments to the first match (!).
It seems the JVM is applying some intelligence here and checks if a path is passed to main() and if so, it automatically resolves wildcards (also quotes are escaped/resolved), which is pretty annoying and not what I want, since I do never see the original parameters this way:(
Is there a way to get the original parameters without the JVM intervening / "helping"?
Any help would be appreciated, as I want my utility to act just like any other shell-program...