code: public Map<String, String> getLayoutMappings() {
  		String mappingsValues = environment.getProperty("mustache.layoutMappings", MustacheSettings.LAYOUT_MAPPINGS).trim();
  
  		if (mappingsValues.isEmpty()) {
  			return emptyMap();
  		}
  
  		Map<String, String> mappings = new HashMap<String, String>();
  		String[] values = mappingsValues.split(";");
  		if (values.length > 0) {
  			for (String value : values) {
  				String val = value == null ? "" : value.trim();
  				if (val.isEmpty()) {
  					continue;
  				}
  
  				String[] mapping = val.split(":");
  				if (mapping.length != 2) {
  					throw new IllegalArgumentException("Mapping must use [viewName]:[layout] format!");
  				}
  
  				mappings.put(mapping[0].trim(), mapping[1].trim());
  			}
  		}
  
  		return unmodifiableMap(mappings);
  	}
docs: Get mappings to use with resolvers.
  
  @return Layouts mappings