package util.filters;import java.io.File;public abstract class SuffixAwareFilter    extends javax.swing.filechooser.FileFilter {  public String getSuffix(File f) {    String s = f.getPath(), suffix = null;    int i = s.lastIndexOf('.');    if (i > 0 && i < s.length() - 1) {      suffix = s.substring(i + 1).toLowerCase();    }    return suffix;  }  public boolean accept(File f) {    return f.isDirectory();  }}