1

From: https://en.wikipedia.org/wiki/Event-driven_architecture

Considering:

Events do not travel, they just occur.

Are the following statements valid?

Event channels are conduits in which events are transmitted from event emitters to event consumers.

...

An event can be made of two parts, the event header and the event body.

Are they talking about event notification or the event itself in the other two quotes?

  • You are ignoring the sentence immediately after the one you quote: "However, the term event is often used metonymically to denote the notification message itself, which may lead to some confusion." It is clear from the context the other quotes are about the notification. – JacquesB Jun 13 '16 at 7:51
  • @JacquesB I read that statement and that is the reason i am confused. They are themselves saying that using word event instead of event notification is confusing they are themselves using it! – Aquarius_Girl Jun 13 '16 at 7:53
  • OK, to answer your question directly, the second and third quote are about the event notification message. – JacquesB Jun 13 '16 at 8:23
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If you quote the following sentence also, you have the answer:

Events do not travel, they just occur. However, the term event is often used metonymically to denote the notification message itself, which may lead to some confusion.

From the context it is clear that the two other quotes are talking about the event notification message rather than the triggering event. It is common to use the word event to describe both the triggering event and the notification message.

The confusion does not stop here. In C# the keyword event is used for the event emitter (which is a multicast delegate, and the event notification object is a parameter to this delegate which will be passed on to all subscribers). In JavaScript/DOM the Event-interface is the base interface for event notification objects. But the term event is also used for the event handlers, e.g. some documentation will use the term "the onlick event" when talking about the event handler which is invoked when the click event is triggered. During the browser wars, Internet Explorer introduced the attachEvent() method which does (almost) exactly the same as addEventListener() in the DOM standard. So the distinction between event and event listener is not clear in the API's either.

In short, the word "event" is used broadly to describe the various different parts which interact in an event driven architecture. So if you need to be precise, it is a good idea to use more specific terms like event notification object, event emitter, event listener and so on.

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