FilenameFilter filter = new PatternFilenameFilter("a+");
    assertTrue(filter.accept(dir, "a"));
    assertTrue(filter.accept(dir, "aaaa"));
    assertFalse(filter.accept(dir, "b"));

    // Show that dir is ignored
    assertTrue(filter.accept(null, "a"));
  }

  public void testNulls() throws Exception {
    NullPointerTester tester = new NullPointerTester();

    super(new EnumMap<K, V>(keyType), new HashMap<V, K>());
    // TODO: cpovirk - Pre-size the HashMap based on the number of enum values?
    this.keyTypeOrObjectUnderJ2cl = keyType;
  }

  // Overriding these 3 methods to show that values may be null (but not keys)

  @Override
  K checkKey(K key) {
    return checkNotNull(key);
  }

  @CanIgnoreReturnValue
  @Override

    FilenameFilter filter = new PatternFilenameFilter("a+");
    assertTrue(filter.accept(dir, "a"));
    assertTrue(filter.accept(dir, "aaaa"));
    assertFalse(filter.accept(dir, "b"));

    // Show that dir is ignored
    assertTrue(filter.accept(null, "a"));
  }

  public void testNulls() throws Exception {
    NullPointerTester tester = new NullPointerTester();

    super(new EnumMap<K, V>(keyType), new HashMap<V, K>());
    // TODO: cpovirk - Pre-size the HashMap based on the number of enum values?
    this.keyTypeOrObjectUnderJ2cl = keyType;
  }

  // Overriding these 3 methods to show that values may be null (but not keys)

  @Override
  K checkKey(K key) {
    return checkNotNull(key);
  }

  @CanIgnoreReturnValue
  @Override

 * weak references.
 *
 * <p><strong>Performance</strong>
 *
 * <p>The extra bookkeeping done by cycle detecting locks comes at some cost to performance.
 * Benchmarks (as of December 2011) show that:
 *
 * <ul>
 *   <li>for an unnested {@code lock()} and {@code unlock()}, a cycle detecting lock takes 38ns as
 *       opposed to the 24ns taken by a plain lock.

 *   }
 * } else {
 *   // do other things since the monitor was not available
 * }
 * }</pre>
 *
 * <h2>Comparison with {@code synchronized} and {@code ReentrantLock}</h2>
 *
 * <p>The following examples show a simple threadsafe holder expressed using {@code synchronized},
 * {@link ReentrantLock}, and {@code Monitor}.
 *
 * <h3>{@code synchronized}</h3>
 *

    public Mall<? extends Outdoor>.Shop<Electronics> ownerTypeIsSubtype_supertypeWithWildcard(
        Outlet<Outdoor>.Shop<Electronics> shop) {
      return isSubtype(shop);
    }

    @TestSubtype(suppressGetSupertype = true, suppressGetSubtype = true)
    public Mall<?>.Shop<Electronics> ownerTypeIsSubtype_withWildcards(
        Outlet<? extends Outdoor>.Shop<Electronics> shop) {
      return isSubtype(shop);
    }

import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

/**
 * File name filter that only accepts files matching a regular expression. This class is thread-safe
 * and immutable.
 *
 * @author Apple Chow
 * @since 1.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class PatternFilenameFilter implements FilenameFilter {

  private final Pattern pattern;

  /**

        fail("mismatch at index " + i + ": " + reportContext(expectedList));
      }
    }
  }

  /**
   * Used to delay string formatting until actually required, as it otherwise shows up in the test
   * execution profile when running an extremely large numbers of tests.
   */
  private String reportContext(List<E> expected) {
    return Platform.format(

          <show>package</show>
        </configuration>
      </plugin>
      <!-- Disable "normal" testing, which doesn't work for GWT tests. -->
      <plugin>
        <artifactId>maven-surefire-plugin</artifactId>