@Override
  public int get(PageId pageId, int bytesToRead, CacheScope cacheScope) {
    mShadowCachePageRead.getAndIncrement();
    mShadowCacheByteRead.getAndAdd(bytesToRead);
    if (mFilter.mightContainAndResetClock(pageId)) {
      mShadowCachePageHit.getAndIncrement();
      mShadowCacheByteHit.getAndAdd(bytesToRead);
      return bytesToRead;
    }
    return 0;
  }
@Test
  public void getNotExist() throws Exception {
    assertEquals(0, mCacheManager.get(PAGE_ID1, PAGE1_BYTES, SCOPE1));
  }