@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class PatternFilenameFilter implements FilenameFilter {

  private final Pattern pattern;

  /**
   * Constructs a pattern file name filter object.
   *
   * @param patternStr the pattern string on which to filter file names
   * @throws PatternSyntaxException if pattern compilation fails (runtime)
   */
  public PatternFilenameFilter(String patternStr) {
    this(Pattern.compile(patternStr));

    // The reason that we skip this method is discussed in a comment on the method.
    tester.ignore(PatternFilenameFilter.class.getMethod("accept", File.class, String.class));
    tester.testInstanceMethods(new PatternFilenameFilter(".*"), Visibility.PACKAGE);
  }