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  3. FMessageEndpoint

FMessageEndpoint

Implements a message endpoint for sending and receiving messages on a message bus.

Unreal Engine C++ API Reference > Runtime > MessagingCommon

Inheritance Hierarchy

References

   
Module MessagingCommon
Header /Engine/Source/Runtime/MessagingCommon/Public/MessageEndpoint.h
Include #include "MessageEndpoint.h"

Syntax

class FMessageEndpoint :  
    public TSharedFromThis< FMessageEndpoint, ESPMode::ThreadSafe >,  
    public IMessageReceiver,  
    public IMessageSender,  
    public IBusListener

Remarks

Implements a message endpoint for sending and receiving messages on a message bus.

This class provides a convenient implementation of the IMessageReceiver and IMessageSender interfaces, which allow consumers to send and receive messages on a message bus. The endpoint allows for receiving messages asynchronously as they arrive, as well as synchronously through an inbox that can be polled.

By default, messages are received synchronously on the thread that the endpoint was created on. If the message consumer is thread-safe, a more efficient message dispatch can be enabled by calling the SetRecipientThread() method with ENamedThreads::AnyThread.

Endpoints that are destroyed or receive messages on non-Game threads should use the static function FMessageEndpoint::SafeRelease() to dispose of the endpoint. This will ensure that there are no race conditions between endpoint destruction and the receiving of messages.

The underlying message bus will take ownership of all sent and published message objects. The memory held by the messages must therefore NOT be freed by the caller.

Constructors

  Type Name Description
Public function  

FMessageEndpoint ( const FName& InName,
const TSharedRef< IMessageBus, ESPMode::ThreadSafe >& InBus,
const TArray< TSharedPtr< IMessageHandler, ESPMode::ThreadSafe >>& InHandlers,
const FOnBusNotification InNotificationDelegate
)

 Creates and initializes a new instance.

Destructors

  Type Name Description
Public function   Destructor.

Functions

  Type Name Description
Protected function void Clears all handlers in a way that guarantees it won't overlap with message processing.
Public function void

Defer ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context,
const FTimespan& Delay
)

 Defers processing of the given message by the specified time delay.
Public function void

Disable ()

 Disables this endpoint.
Public function void Disables the inbox for unhandled messages.The inbox is disabled by default.
Public function void

Enable ()

 Enables this endpoint.
Public function void Enables the inbox for unhandled messages.
Public function void

Forward ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay
)

 Forwards a previously received message.
Public function void

Forward ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context,
const FMessageAddress& Recipient,
const FTimespan& Delay
)

 Forwards a previously received message to the specified recipient after a given delay.
Public function void

Forward ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context,
const FMessageAddress& Recipient
)

 Immediately forwards a previously received message to the specified recipient.
Public function void

Forward ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context,
const TArray< FMessageAddress >& Recipients
)

 Immediately forwards a previously received message to the specified list of recipients.
Public function Const const FMessageAddress & Gets the endpoint's message address.
Protected function Const TSharedPtr< IMessageBus, ESPMode::ThreadSafe > Gets a shared pointer to the message bus if this endpoint is enabled.
Public function Const bool Checks whether this endpoint is connected to the bus.
Public function Const bool Checks whether this endpoint is enabled.
Public function Const bool Checks whether the inbox is empty.
Public function Const bool Checks whether the inbox is enabled.
Public function Static T *

MakeMessage ( InArgTypes&&... Args
)

 Creates a message of the specified template type.
Public function void Calls the matching message handlers for all messages queued up in the inbox.
Protected function void

ProcessMessage ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context
)

 Forwards the given message context to matching message handlers.
Public function void
Publish

( void* Message,
UScriptStruct* TypeInfo,
EMessageScope Scope,
const TMap< FName, FString > Annotations,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Publishes a message to all subscribed recipients within the specified scope.
Public function void
Publish

( MessageType* Message,
const TMap< FName, FString > Annotations,
EMessageScope Scope,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Publishes a message to all subscribed recipients within the specified scope.
Public function void
Publish

( void* Message,
UScriptStruct* TypeInfo,
EMessageScope Scope,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Publishes a message to all subscribed recipients within the specified scope.
Public function void
Publish

( MessageType* Message,
EMessageScope Scope,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Publishes a message to all subscribed recipients within the specified scope.
Public function void
Publish

( MessageType* Message,
const TMap< FName, FString > Annotations,
EMessageScope Scope
)

 Immediately pa message to all subscribed recipients within the specified scope.
Public function void
Publish

( MessageType* Message,
EMessageScope Scope,
const FTimespan& Delay
)

 Publishes a message to all subscribed recipients within the specified scope after a given delay.
Public function void
Publish

( MessageType* Message,
const FTimespan& Delay
)

 Publishes a message to all subscribed recipients after a given delay.
Public function void
Publish

( MessageType* Message
)

 Immediately publishes a message to all subscribed recipients.
Public function void
Publish

( MessageType* Message,
EMessageScope Scope
)

 Immediately pa message to all subscribed recipients within the specified scope.
Public function void
Publish

( MessageType* Message,
const TMap< FName, FString > Annotations
)

 Immediately publishes a message to all subscribed recipients.
Public function bool

ReceiveFromInbox ( TSharedPtr< IMessageContext, ESPMode::ThreadSafe >& OutContext
)

 Receives a single message from the endpoint's inbox.
Public function Static void

SafeRelease ( TSharedPtr< FMessageEndpoint, ESPMode::ThreadSafe >& Endpoint
)

 Safely releases a message endpoint that is receiving messages on AnyThread.
Public function void

Send ( void* Message,
UScriptStruct* TypeInfo,
EMessageFlags Flags,
const TMap< FName, FString > Annotations,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Sends a message to the specified list of recipients.
Public function void

Send ( MessageType* Message,
EMessageFlags Flags,
const TMap< FName, FString > Annotations,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Sends a message to the specified list of recipients. Allows to specify message flags
Public function void

Send ( void* Message,
UScriptStruct* TypeInfo,
EMessageFlags Flags,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Sends a message to the specified list of recipients. Allows to specify message flags
Public function void

Send ( MessageType* Message,
EMessageFlags Flags,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Sends a message to the specified list of recipients. Allows to specify message flags
Public function void

Send ( MessageType* Message,
const TMap< FName, FString > Annotations,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const FMessageAddress& Recipient,
const FDateTime& Expiration,
const FTimespan& Delay
)

 Sends a message with fields, attachment and expiration to the specified recipient after a given delay.
Public function void

Send ( MessageType* Message,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Sends a message to the specified list of recipients.
Public function void

Send ( MessageType* Message,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay
)

 Sends a message with fields and attachment to the specified list of recipients after a given delay.
Public function void

Send ( MessageType* Message,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const FMessageAddress& Recipient,
const FDateTime& Expiration,
const FTimespan& Delay
)

 Sends a message with fields, attachment and expiration to the specified recipient after a given delay.
Public function void

Send ( MessageType* Message,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay
)

 Sends a message to the specified list of recipients after a given delay after a given delay.
Public function void

Send ( MessageType* Message,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const FMessageAddress& Recipient
)

 Sends a message with fields and attachment to the specified recipient.
Public function void

Send ( MessageType* Message,
const FMessageAddress& Recipient,
const FTimespan& Delay
)

 Sends a message to the specified recipient after a given delay.
Public function void

Send ( MessageType* Message,
const TMap< FName, FString > Annotations,
const FMessageAddress& Recipient
)

 Immediately sends a message to the specified recipient.
Public function void

Send ( MessageType* Message,
const TArray< FMessageAddress >& Recipients
)

 Immediately sends a message to the specified list of recipients.
Public function void

Send ( MessageType* Message,
const FMessageAddress& Recipient
)

 Immediately sends a message to the specified recipient.
Public function void

Send ( MessageType* Message,
const FMessageAddress& Recipient,
const FTimespan& Delay,
const FDateTime& Expiration
)

 Sends a message with fields and expiration to the specified recipient after a given delay.
Public function void

SetRecipientThread ( const ENamedThreads::Type& NamedThread
)

 Sets the name of the thread to receive messages on.
Public function void Template method to subscribe the message endpoint to the specified type of messages with the default message scope.
Public function void

Subscribe ( const FMessageScopeRange& ScopeRange
)

 Template method to subscribe the message endpoint to the specified type and scope of messages.
Public function void

Subscribe ( const FTopLevelAssetPath& MessageType,
const FMessageScopeRange& ScopeRange
)

 Subscribes a message handler.
Public function void Unsubscribes this endpoint from all message types.
Public function void Template method to unsubscribe the endpoint from the specified message type.
Public function void

Unsubscribe ( const FTopLevelAssetPath& MessageType
)

 Unsubscribes this endpoint from the specified message type.

Overridden from IMessageReceiver

  Type Name Description
Public function Virtual Const FName Gets the recipient's name (for debugging purposes).
Public function Virtual Const const FGuid & Gets the recipient's unique identifier (for debugging purposes).
Public function Virtual Const ENamedThreads::Type Gets the name of the thread on which to receive messages.
Public function Virtual Const bool

IsLocal ()

 Checks whether this recipient represents a local endpoint.
Public function Virtual void

ReceiveMessage ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context
)

 Handles the given message.

Overridden from IMessageSender

  Type Name Description
Public function Virtual FMessageAddress Gets the sender's address.
Public function Virtual void

NotifyMessageError ( const TSharedRef< IMessageContext, ESPMode::ThreadSafe >& Context,
const FString& Error
)

 Notifies the sender of errors.

Overridden from IBusListener

  Type Name Description
Public function Virtual Const ENamedThreads::Type Gets the name of the thread on which to receive notifications.
Public function Virtual void

NotifyRegistration ( const FMessageAddress& Address,
EMessageBusNotification Notification
)

 Notify a registration event from the bus This is called when a receiver is registered or unregistered from the bus.

Typedefs

Name Description
Builder Type definition for the endpoint builder.

Deprecated Functions

  Type Name Description
Public function void

Send ( void* Message,
UScriptStruct* TypeInfo,
const TSharedPtr< IMessageAttachment, ESPMode::ThreadSafe >& Attachment,
const TArray< FMessageAddress >& Recipients,
const FTimespan& Delay,
const FDateTime& Expiration
)

 FMessageEndpoint::Send with 6 params is deprecated. Please use FMessageEndpoint::Send that takes additionnal EMessageFlags instead!
Public function void

Subscribe ( const FName& MessageType,
const FMessageScopeRange& ScopeRange
)

 Types names are now represented by path names. Please use a version of this function that takes an FTopLevelAssetPath as MessageType.
Public function void

Unsubscribe ( const FName& MessageType
)

 Types names are now represented by path names. Please use a version of this function that takes an FTopLevelAssetPath as MessageType.

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