AbstractCache implements IDataCache<T> { @Override public void clearCache() { lock.writeLock().lock(); try { entries.clear(); currentCacheSize = 0; } finally { lock.writeLock().unlock(); } } AbstractCache(S entries, IDataStorage<T> cachedStorage, long maxCacheSize,
      Predicate<T> cachingRule); @Override long getMaxCacheSize(); @Override boolean setMaxCacheSize(long maxCacheSize); @Override long getCurrentCacheSize(); @Override long getFreeSpace(); @Override boolean hasStorageFor(long size); @Override void cacheData(T data); @Override void uncacheData(T data); @Override boolean dataIsCachable(T data); @Override boolean dataIsInCache(long id); @Override void clearCache(); @Override boolean dataExists(long id); @Override T loadData(long id); @Override boolean saveData(T data); @Override boolean dataIsStorable(T data); @Override boolean deleteData(T data);  }
@Test public void testClearCache() { AbstractCacheWrapper uut = new AbstractCacheWrapper(entries, storageAll, 20000, predicate -> true); uut.clearCache(); uut.cacheData(c0); uut.cacheData(c1); assertTrue(uut.dataIsInCache(c0.getId())); assertTrue(uut.dataIsInCache(c1.getId())); uut.clearCache(); assertFalse(uut.dataIsInCache(c0.getId())); assertFalse(uut.dataIsInCache(c1.getId())); }