code: public Map<?, ?> getByContainer() {
  
          if (m_byContainer == null) {
              m_byContainer = CmsCollectionsGenericWrapper.createLazyMap(new Transformer() {
  
                  public Object transform(Object arg0) {
  
                      String key = (String)arg0;
                      CmsContainerBean container = m_page.getContainers().get(key);
                      if (container == null) {
                          return Collections.emptyList();
                      } else {
                          return container.getElements();
                      }
                  }
              });
          }
          return m_byContainer;
      }
docs: Gets lazy map that returns lists of element beans for the container whose name is given as a key.<p>
  
  @return a lazy map to fetch contents of a container