code: protected boolean readCache() {
          if (this.cache != null) {
              if (this.cache.isCached(resourceId)) {
                  byte[] data = this.cache.read(resourceId);
                  if (data != null) {
                      setData(data);
                      return true;
                  }
              }
          }
          return false;
      }
docs: This method is called when the data should be loaded from the cache. This method abstracts the effective
  caching mechanism implemented. By default it tries to read a file from the current user's home directory.
  If the data could be read, #setData(byte[]) should be called to apply the data read.
  
  @return true, if data could be read and applied from the cache sucdcessfully.