2. Software Application Event Driven Architecture (EDA) design pattern | Tutorial with example смотреть онлайн

This video explains about one among the commonly used software architecture called, event driven architecture EDA, which is also known as message driven architecture.
An event can be defined as a, 'significant change in state'.
So whenever there is a significant change in the state of a application or a variable, it triggers the event.
This event in turn, emits a message or notification.
Normally in an event driven architecture of software applications, there will be three roles involved.
First is Event Source, where the event occurs and the message is triggered.
Second is the Event Consumer, which receives and interpret the message that is triggered from event source.
Third is Event bus or the middle ware which receives the message from source and forward it to consumer. Though this event bus is an optional element, it recommended to have it in the event driven architecture.
There are two types of typologies are used in event driven architecture.
Mediator topology broker topology
The mediator topology is useful for events that have multiple steps and require some level of orchestration to process the event.
There are four main types of architectural components within the mediator topology: event queues, an event mediator, event channels, and event processors.
The broker topology differs from the mediator topology in the way that, there is no central event mediator.
Rather, the message flow is distributed across the event processor components in a chain like fashion through a lightweight message broker.
This topology is useful when you have a relatively simple event processing flow and you do not want central event orchestration.
There are two main types of architectural components within the broker topology:
a broker component and an event processor component.