code: private String getCacheKeyForCurrentProject(String systemId) {
  
          // check the project
          boolean project = (m_cms != null) ? m_cms.getRequestContext().getCurrentProject().isOnlineProject() : false;
  
          // remove opencms:// prefix
          if (systemId.startsWith(OPENCMS_SCHEME)) {
              systemId = systemId.substring(OPENCMS_SCHEME.length() - 1);
          }
  
          return getCacheKey(systemId, project);
      }
docs: Returns a cache key for the given system id (filename) based on the status
  of the internal CmsObject.<p>
  
  @param systemId the system id (filename) to get the cache key for
  
  @return the cache key for the system id