}

    @Nullable
    public static Path findRoot(Path topDirectory) {
        requireNonNull(topDirectory, "topDirectory");
        Path rootDirectory =
                ServiceLoader.load(RootLocator.class).iterator().next().findRoot(topDirectory);
        if (rootDirectory != null) {
            return getCanonicalPath(rootDirectory);
        }
        return null;
    }

    @Nonnull

          @Override
          public Iterator<Entry<Range<K>, V>> iterator() {
            return entryIterator();
          }

          @Override
          public boolean retainAll(Collection<?> c) {
            return removeEntryIf(not(in(c)));
          }

          @Override
          public int size() {
            return Iterators.size(iterator());
          }

          @Override

  }

  static <T extends @Nullable Object> Iterator<T> cycle(Iterable<T> iterable) {
    return new Iterator<T>() {
      Iterator<T> iterator = Collections.<T>emptySet().iterator();

      @Override
      public boolean hasNext() {
        return true;
      }

      @Override
      public T next() {
        if (!iterator.hasNext()) {
          iterator = iterable.iterator();
        }

      return frequency;
    }

    @Override
    Iterator<E> elementIterator() {
      return Multisets.elementIterator(entryIterator());
    }

    @Override
    Iterator<Entry<E>> entryIterator() {
      final Iterator<Map.Entry<E, Integer>> backingEntries = backingMap.entrySet().iterator();
      return new UnmodifiableIterator<Multiset.Entry<E>>() {
        @Override

      return;
    }

    Set<Entry<K, V>> entrySet = map.entrySet();
    Iterator<Entry<K, V>> iterator = entrySet.iterator();
    if (supportsIteratorRemove) {
      int initialSize = map.size();
      Entry<K, V> entry = iterator.next();
      Entry<K, V> entryCopy = mapEntry(entry.getKey(), entry.getValue());

      iterator.remove();
      assertEquals(initialSize - 1, map.size());

              throw new NoSuchElementException();
            }
            return array[i++];
          }
        };

    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertThrows(UnsupportedOperationException.class, () -> iterator.remove());
  }

    }

    @Override
    public Iterator<E> iterator() {
      return Multisets.elementIterator(multiset().entrySet().iterator());
    }
  }

  /**
   * A sensible definition of {@link #iterator} in terms of {@link #entrySet} and {@link
   * #remove(Object)}. If you override either of these methods, you may wish to override {@link
   * #iterator} to forward to this implementation.
   *
   * @since 7.0

  public void testPutAbsentConcurrentWithEntrySetIteration() {
    assertThrows(
        ConcurrentModificationException.class,
        () -> {
          Iterator<Entry<K, V>> iterator = getMap().entrySet().iterator();
          put(e3());
          iterator.next();
        });
  }

  @MapFeature.Require({FAILS_FAST_ON_CONCURRENT_MODIFICATION, SUPPORTS_PUT})
  @CollectionSize.Require(absent = ZERO)

 * the License.
 */

package com.google.common.cache;

import com.google.common.annotations.GwtCompatible;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentMap;

/**
 * The reason why a cached entry was removed.
 *
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible

import com.google.common.collect.TestExceptions.SomeUncheckedException;
import com.google.common.testing.GcFinalization;
import java.lang.ref.WeakReference;
import java.util.Iterator;
import java.util.NoSuchElementException;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Unit test for {@code AbstractIterator}.
 *