* higher value than you need can waste space and time, and a significantly lower value can lead
   * to thread contention. But overestimates and underestimates within an order of magnitude do not
   * usually have much noticeable impact. A value of one permits only one thread to modify the map
   * at a time, but since read operations can proceed concurrently, this still yields higher

 * read-write locks. Conceptually, lock striping is the technique of dividing a lock into many
 * <i>stripes</i>, increasing the granularity of a single lock and allowing independent operations
 * to lock different stripes and proceed concurrently, instead of creating contention for a single
 * lock.
 *
 * <p>The guarantee provided by this class is that equal keys lead to the same lock (or semaphore),

          assertTrue(entries.add(current));
          if (prev != null) {
            assertSame(prev, current.getPreviousInAccessQueue());
            assertSame(prev.getNextInAccessQueue(), current);
            // read accesses may be slightly misordered
            assertTrue(
                prev.getAccessTime() <= current.getAccessTime()
                    || prev.getAccessTime() - current.getAccessTime() < 1000);
          }

   *   <li><b>If the character at the specified index is not a surrogate, it is returned.</b>
   *   <li>If the first character was a high surrogate value, then an attempt is made to read the
   *       next character.
   *       <ol>
   *         <li><b>If the end of the sequence was reached, the negated value of the trailing high
   *             surrogate is returned.</b>

 * entries may be counted in {@link Cache#size}, but will never be visible to read or write
 * operations.
 *
 * <p>Certain cache configurations will result in the accrual of periodic maintenance tasks which
 * will be performed during write operations, or during occasional read operations in the absence of
 * writes. The {@link Cache#cleanUp} method of the returned cache will also perform maintenance, but

  private final ListenerCallQueue<Listener> listeners = new ListenerCallQueue<>();

  /**
   * The current state of the service. This should be written with the lock held but can be read
   * without it because it is an immutable object in a volatile field. This is desirable so that
   * methods like {@link #state}, {@link #failureCause} and notably {@link #toString} can be run
   * without grabbing the lock.

    assertEquals(2, lin.available());
    int read = lin.read();
    assertEquals(big[0], read);
    assertEquals(1, lin.available());
    read = lin.read();
    assertEquals(big[1], read);
    assertEquals(0, lin.available());
    read = lin.read();
    assertEquals(-1, read);

    lin.reset();
    byte[] small = new byte[5];
    read = lin.read(small);
    assertEquals(2, read);
    assertEquals(big[0], small[0]);

    assertEquals(-1, counter.read());
    assertEquals(20, counter.getCount());
  }

  public void testReadArrayEOF() throws IOException {
    assertEquals(20, counter.read(new byte[30]));
    assertEquals(20, counter.getCount());
    assertEquals(-1, counter.read(new byte[30]));
    assertEquals(20, counter.getCount());
  }

  @SuppressWarnings("CheckReturnValue") // calling read() to skip a byte

   * Returns the total number of chars read. Does not close the stream.
   *
   * @since 20.0
   */
  @CanIgnoreReturnValue
  public static long exhaust(Readable readable) throws IOException {
    long total = 0;
    long read;
    CharBuffer buf = createBuffer();
    while ((read = readable.read(buf)) != -1) {
      total += read;
      Java8Compatibility.clear(buf);
    }
    return total;

    List<E> head = list.subList(0, size - 1);
    List<E> tail = list.subList(1, size);
    assertEquals(list.get(0), copy.get(0));
    assertEquals(list.get(size - 1), copy.get(size - 1));
    assertEquals(list.get(1), tail.get(0));
    assertEquals(list.get(size - 1), tail.get(size - 2));
    assertEquals(list.get(0), head.get(0));
    assertEquals(list.get(size - 2), head.get(size - 2));