code: @Override
      public Set getCacheIdsByDependencyDisk(Object depId) {
          final String methodName = "getCacheIdsByDependencyDisk()";
          Set ids = new HashSet();
          if (this.swapToDisk) {
              // TODO write code to support getCacheIdsByDependencyDisk function
              if (tc.isDebugEnabled()) {
                  Tr.debug(tc, methodName + " cacheName=" + cacheName + " ERROR because it is not implemented yet");
              }
          } else {
              if (this.featureSupport.isDiskCacheSupported() == false) {
                  Tr.error(tc, "DYNA1064E", new Object[] { methodName, cacheName, this.cacheProviderName });
              } else {
                  if (tc.isDebugEnabled()) {
                      Tr.debug(tc, methodName + " cacheName=" + cacheName + " no operation is done because the disk cache offload is not enabled");
                  }
              }
          }
          return ids;
      }
docs: Returns the cache IDs that are associated with a dependency ID from the
  disk cache. It returns an empty set if no cache ID is associated with it.
  <p>
  <br>
  Dependency elements are used to group related cache items. Cache entries
  having the same depenendency ID are managed as a group. Each related
  cache item shares the same dependency id, so it only takes one member of
  the dependency group to get invalidated, for the rest of the group to be
  evicted. The dependency ID can be as simple as just a name such as
  storeId
  
  @param depId
  dependency ID for the groupof cache IDs.
  @return A set of cache IDs or empty set if no cache ID is
  associated with it.