@ElementTypesAreNonnullByDefault
public abstract class Ticker {
  /** Constructor for use by subclasses. */
  protected Ticker() {}

  /** Returns the number of nanoseconds elapsed since this ticker's fixed point of reference. */
  public abstract long read();

  /**
   * A ticker that reads the current time using {@link System#nanoTime}.
   *
   * @since 10.0
   */
  public static Ticker systemTicker() {
    return SYSTEM_TICKER;
  }

  public void testAdvance() {
    FakeTicker ticker = new FakeTicker();
    assertEquals(0, ticker.read());
    assertSame(ticker, ticker.advance(10));
    assertEquals(10, ticker.read());
    ticker.advance(1, TimeUnit.MILLISECONDS);
    assertEquals(1000010L, ticker.read());
    ticker.advance(Duration.ofMillis(1));
    assertEquals(2000010L, ticker.read());
  }

  public void testAutoRefresh() {
    FakeTicker ticker = new FakeTicker();
    IncrementingLoader loader = incrementingLoader();
    LoadingCache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .refreshAfterWrite(3, MILLISECONDS)
            .expireAfterWrite(6, MILLISECONDS)
            .lenientParsing()
            .ticker(ticker)
            .build(loader);
    int expectedLoads = 0;

  }

  public void testTicker_setTwice() {
    Ticker testTicker = Ticker.systemTicker();
    CacheBuilder<Object, Object> builder = CacheBuilder.newBuilder().ticker(testTicker);
    try {
      // even to the same instance is not allowed
      builder.ticker(testTicker);
      fail();
    } catch (IllegalStateException expected) {
    }
  }

     * Program will use this name to require service ticket from KDC.
     *
     * @param name
     *            the service name used to require service ticket from KDC.
     */
    public void setService ( String name ) {
        this.service = name;
    }


    /**
     * Get the service name.
     *
     * @return the service name used to require service ticket from KDC
     */

    assertEquals("valueStrength", a.valueStrength, b.valueStrength);
    assertEquals("statsCounterSupplier", a.statsCounterSupplier, b.statsCounterSupplier);
    assertEquals("ticker", a.ticker, b.ticker);
    assertEquals("recordStats", a.isRecordingStats(), b.isRecordingStats());
  }

      @Override
      public String toString() {
        return string;
      }
    };
  }

  @Generates
  Ticker generateTicker() {
    return new Ticker() {
      @Override
      public long read() {
        return 0;
      }

      final String string = paramString(Ticker.class, generateInt());

      @Override
      public String toString() {
        return string;
      }
    };

            .expireAfterWrite(EXPIRING_TIME, MILLISECONDS)
            .removalListener(removalListener)
            .ticker(ticker)
            .build(loader);
    checkExpiration(cache, loader, ticker, removalListener);
  }

  public void testExpiration_expireAfterAccess() {
    FakeTicker ticker = new FakeTicker();
    CountingRemovalListener<String, Integer> removalListener = countingRemovalListener();

  }

  public void testElapsed_notRunning() {
    ticker.advance(1);
    stopwatch.start();
    ticker.advance(4);
    stopwatch.stop();
    ticker.advance(9);
    assertEquals(4, stopwatch.elapsed(NANOSECONDS));
  }

  public void testElapsed_multipleSegments() {
    stopwatch.start();
    ticker.advance(9);
    stopwatch.stop();

    ticker.advance(16);

    stopwatch.start();

import com.google.common.annotations.J2ktIncompatible;
import com.google.common.base.Ticker;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.time.Duration;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicLong;

/**
 * A Ticker whose value can be advanced programmatically in test.
 *
 * <p>The ticker can be configured so that the time is incremented whenever {@link #read} is called: