import java.io.File;
import java.io.FilenameFilter;

public class Filter implements FilenameFilter {
  protected String pattern;
  public Filter (String str) {
    pattern = str;
  }
  
  public boolean accept (File dir, String name) {
    return name.toLowerCase().endsWith(pattern.toLowerCase());
  }
  
  public static void main (String args[]) {
    if (args.length != 1) {
       System.err.println
          ("usage: java Filter <pattern list>  ex. java Filter java");
       return;
    }
    
    Filter nf = new Filter (args[0]);
    // current directory
    File dir = new File (".");
    String[] strs = dir.list(nf);
    for (int i = 0; i < strs.length; i++) {
      System.out.println (strs[i]);
    }
  }
}

import java.io.File;
import java.io.FilenameFilter;
import java.util.*;
import java.util.TreeSet.*;

public class Filter implements FilenameFilter {
  protected Set extensionsSet;

  public Filter (String [] extensions) {
    extensionsSet = new TreeSet();

    for (Iterator ext=Arrays.asList(extensions).iterator(); 
            ext.hasNext();) 
    {
      extensionsSet.add(ext.next().toString().toLowerCase().trim());
    }
    extensionsSet.remove("");
  }

  public boolean accept (File dir, String name) {
    final Iterator exts = extensionsSet.iterator();
    while (exts.hasNext()) {
      if (name.toLowerCase().endsWith(exts.next().toString())) {
          return true;
      }
    }
    return false;
  }


  public static void main (String args[]) {
    if (args.length < 1) {
       System.err.println 
          ("usage: java Filter <pattern list>  ex. java Filter java txt");
       return;
    }
    Filter nf = new Filter (args);
    // current directory
    File dir = new File (".");
    String[] strs = dir.list(nf);
    for (int i = 0; i < strs.length; i++) {
      System.out.println (strs[i]);
    }
  }
}

import java.io.File;
import java.io.FilenameFilter;
import java.util.regex.*;

public class Filter implements FilenameFilter {

  public boolean accept (File dir, String name) {
    return Pattern.matches(".*\\.(jpg|jpeg|gif|png|bmp)", name);
    //  if only one extension to check :  "\\.jpg"
  }

  public static void main (String args[]) {
    if (args.length < 1) {
       System.err.println 
          ("usage: java Filter <directory>  ex. java Filter c:\\temp");
       return;
    }
    Filter nf = new Filter();
    // current directory
    File dir = new File (args[0]);
    String[] strs = dir.list(nf);
    for (int i = 0; i < strs.length; i++) {
      System.out.println (strs[i]);
    }
  }
}