Messaging Channels

A Message channel is a basic architectural pattern of a messaging system and is used fundamentally for exchanging data between applications. An application can use a channel to make a specific type of data available to any receiver applications that need to consume that type of data.

This chapter introduces different types of channels used in a messaging system, their behaviors, and how each of them can be simulated using WSO2 ESB.

	Point-to-Point Channel	How the caller can be sure that exactly one receiver will receive the document or perform the call.
	Publish-Subscribe Channel	How the sender broadcasts an event to all interested receivers.
	Datatype Channel	How the application sends a data item such that the receiver will know how to process it.
	Invalid Message Channel	How a messaging receiver gracefully handles a message that makes no sense.
	Dead Letter Channel	What the messaging system does with a message it cannot deliver.
	Guaranteed Delivery	How the sender ensures delivery of a message, even if the messaging system fails.
	Channel Adapter	How to connect an application to the messaging system to send/receive messages.
	Messaging Bridge	How multiple messaging systems can be connected so that messages available on one are also available on the others.
	Message Bus	An architecture enabling separate applications to work together in a decoupled fashion such that applications can be easily added or removed without affecting the others.