/** Builder for projects/{project_number}/settings/{setting_name}. */                              
public static class Builder {                                                                      
    private String projectNumber;                                                                    
    private String settingName; 

    // Existing code here.                                                                 
                                                                                                                                                                                                                                          
    private Builder(SettingName settingName) {                                                       
      Preconditions.checkArgument(                                                                   
          Objects.equals(settingName.pathTemplate, PROJECT_NUMBER_SETTING_NAME),                     
          "toBuilder is only supported when SettingName has the pattern of projects/{project_number}/settings/{setting_name}");
      projectNumber = settingName.projectNumber;                                                
      settingName = settingName.settingName;                                                    
    }                                                                                             
}