code: @Override
      public CacheConfiguration<K, V> addCacheEntryListenerConfiguration(
              CacheEntryListenerConfiguration<K, V> cacheEntryListenerConfiguration) {
  
          checkNotNull(cacheEntryListenerConfiguration, "CacheEntryListenerConfiguration can't be null");
          if (!getListenerConfigurations().add(cacheEntryListenerConfiguration)) {
              throw new IllegalArgumentException("A CacheEntryListenerConfiguration can "
                      + "be registered only once");
          }
          return this;
      }
docs: Add a configuration for a {@link javax.cache.event.CacheEntryListener}.
  
  @param cacheEntryListenerConfiguration the {@link CacheEntryListenerConfiguration}
  @return the {@link CacheConfig}
  @throws IllegalArgumentException if the same CacheEntryListenerConfiguration
  is used more than once