@Override
    public boolean containsKey(K key) {
        begin();
        boolean result = transactionalMap.containsKey(key);
        commit();
        return result;
    }
@Test
    public void testContainsKey() {
        map.put(23, "value-23");

        assertTrue(adapter.containsKey(23));
        assertFalse(adapter.containsKey(42));
    }