code: public boolean contains(String resource) {
  		boolean result = storage.contains(resource);
  		logger.debug("resource '{}' {} in cache", resource, (result ? "is" : "is not"));
  		return result; 
  	}
docs: Checks whether the cache contains the given resource.
  
  @param resource
  the resource whose existence in the cache is to be checked.
  @return
  <code>true</code> if the resource exists in the cache, <code>false
  </code> otherwise.