}
          }
        };

    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.peek());
    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.next());

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    /*
     * We test peek() after various calls to make sure that one bad call doesn't interfere with its

            }
          }
        };

    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.peek());
    assertTrue(iter.hasNext());
    assertEquals(0, (int) iter.peek());
    assertEquals(0, (int) iter.next());

    assertEquals(1, (int) iter.peek());
    assertEquals(1, (int) iter.next());

    /*
     * We test peek() after various calls to make sure that one bad call doesn't interfere with its

    assertSame(EntryFactory.WEAK, EntryFactory.getFactory(Strength.WEAK, false, false));
    assertSame(EntryFactory.WEAK_ACCESS, EntryFactory.getFactory(Strength.WEAK, true, false));
    assertSame(EntryFactory.WEAK_WRITE, EntryFactory.getFactory(Strength.WEAK, false, true));
    assertSame(EntryFactory.WEAK_ACCESS_WRITE, EntryFactory.getFactory(Strength.WEAK, true, true));
  }

  // computation tests

    assertSame(EntryFactory.WEAK, EntryFactory.getFactory(Strength.WEAK, false, false));
    assertSame(EntryFactory.WEAK_ACCESS, EntryFactory.getFactory(Strength.WEAK, true, false));
    assertSame(EntryFactory.WEAK_WRITE, EntryFactory.getFactory(Strength.WEAK, false, true));
    assertSame(EntryFactory.WEAK_ACCESS_WRITE, EntryFactory.getFactory(Strength.WEAK, true, true));
  }

  // computation tests

import com.google.common.annotations.VisibleForTesting;
import com.google.common.math.IntMath;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.Weak;
import com.google.j2objc.annotations.WeakOuter;
import java.util.AbstractQueue;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

      STRONG_ACCESS,
      STRONG_WRITE,
      STRONG_ACCESS_WRITE,
      WEAK,
      WEAK_ACCESS,
      WEAK_WRITE,
      WEAK_ACCESS_WRITE,
    };

    static EntryFactory getFactory(
        Strength keyStrength, boolean usesAccessQueue, boolean usesWriteQueue) {
      int flags =
          ((keyStrength == Strength.WEAK) ? WEAK_MASK : 0)
              | (usesAccessQueue ? ACCESS_MASK : 0)

    assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() middle element multiple times", "B", peekingIterator.peek());
    assertEquals(

    assertEquals(
        "next() should still return first element after peeking", "A", peekingIterator.next());

    assertEquals("Should be able to peek() at middle element", "B", peekingIterator.peek());
    assertEquals(
        "Should be able to peek() middle element multiple times", "B", peekingIterator.peek());
    assertEquals(

import com.google.common.annotations.VisibleForTesting;
import com.google.common.math.IntMath;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.j2objc.annotations.Weak;
import com.google.j2objc.annotations.WeakOuter;
import java.util.AbstractQueue;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

   *   <li>clearing weak references to unreachable referents
   *   <li>enqueuing weak references to unreachable referents in their reference queue
   * </ul>
   */
  @DoNotMock("Implement with a lambda")
  public interface FinalizationPredicate {
    boolean isDone();
  }

  /**
   * Waits until the given weak reference is cleared, invoking the garbage collector as necessary to