public Object put(K key, SqlConstraint constraint, V value) {
   Object cacheKey = constraint.getCacheKey();
   if (cacheKey == null) {
     return null;
   }
   Key2<K, Object> key2 = new Key2<K, Object>(key, cacheKey);
   return cache.put(key2, value);
 }
 public V get(K key, SqlConstraint constraint) {
   Key2<K, Object> key2 = new Key2<K, Object>(key, constraint.getCacheKey());
   return cache.get(key2);
 }