Messaging - JayhawkZombie/EECS581Project GitHub Wiki

Messaging

Internal Messaging

You can use the internal messaging system by interfacing with the Engine::Messager singleton.

There are several ways to post a message:

If you know the InternalID for the object you want to communicate with, use this method:
```
static bool PostMessageForInstance(std::uint32_t Source, std::uint32_t Destination, const SystemMessage &Message)       
```
- Whenever that instanced object polls for messages, yours will be there
If you know the name of the class you want to communicate with, use this method:
```
static bool PostMessageForClass(std::uint32_t Source, const std::string ReceivingClass, const SystemMessage &Message)        
```
- Whenever that class polls for messages, yours will be there

If you wish to post to the log, use this method:

static bool PostLogMessage(std::uint32_t Source, const SystemMessage &Message, MessageLogLevel Level)

If you wish to post to the activity log, use this method:

static bool PostToActivityLog(const SystemMessage &Message)

You can construct a SystemMessage object using its constructor as follows:

SystemMessage(SystemMessageType MessageType, std::uint32_t Source, std::uint32_t Destination, const std::string &Post)

SystemMessageType is an enum designed to clarify the reason for the post, and its possible values are:

enum class SystemMessageType : std::uint32_t
{
  // An incoming notification
  Notification = 0                    ,

  // Some type of incoming engine request
  Request                             ,

  // Some type of critical message
  Critical                            ,

  //Activity log
  ActivityLog
};

MessageLogLevel is designed to signal the intent of the log and note if it is a routine log or documentation of some error. It's possible values are:

enum class MessageLogLevel : std::uint32_t
{
  //Just a message - for testing / monitoring - assume a valid state
  Normal = 0                          ,

  // Elevated - for debugging - assume a valid state, but be prepared for unexpected behavior
  Elevated                            ,

  // High - For reporting errors - do not assume a valid state
  High                                ,

  //Critical - for failures - be prepared for a potential crash
  Critical                            ,

  //Unrecoverable - we're going down
  Unrecoverable
};

You do not need to retrieve the singleton's instance. It will be created by calling Engine::Messager::Init() inside Startup.cpp and will be destroyed by calling Engine::Messager::Shutdown() inside 'Shutdown.cpp`. There is not public method available to retrieve the singleton instance. All intended functionality can be implemented using the public interface methods described above.

Example of posting a log message:

Messager::PostLogMessage(0, SystemMessage(SystemMessageType::ActivityLog, 0, 0, "EngineStartup"), MessageLogLevel::Normal);

Example of posting to the activity log:

PostToActivityLog(SystemMessage(SystemMessageType::ActivityLog, Source, 0, ALogMsg));