java模板函数的应用

protected static <K extends KeyValues> K getKeyValuesByCacheMap(Class<K> keyValuesType, ConcurrentMap<Object, Object> cacheMap, Object[] values)
  {
    ConcurrentMap parentMap = cacheMap;
    for (Object val : values) {
      if (parentMap == null) {
        break;
      }

      Object o = parentMap.get((val != null) ? val : "");
      if (keyValuesType.isInstance(o))
      {
        return ((KeyValues)o);
      }
      parentMap = null;
      if (!(o instanceof ConcurrentMap))
        continue;
      parentMap = (ConcurrentMap)o;

    }

    return null;
  }