Skip to main content

The Yin and Yang of Actions and Events

Today, in our telcon we invented something. It is not often that we can claim that; but today we did.

There are, it sometimes seems, people who think that everything is an event. There are others (including a lot of philosophers) who think everything is an action. (Well, everything that people are involved with anyway.)

Well, they are wrong.

In human communication, the only way of getting someone to understand something you want them to is by saying something to them: by performing one or more speech actions. In the SOA we interpret this by committing to a view that participants in a service interaction denote the actions to be performed by exchanging messages. I.e., an appropriately formatted message that is effectively communicated between participants counts as an effort to perform an action.

But, not all messages encode actions. Some encode events. For us, an event can be defined as something that happened that someone has an interest in. We can encode a description of an event as a message, in exactly the same way that an action can be so encoded.

So, what is the relationship between events and actions?

If you look at the message that denotes the action, you can call it an event (the event is the performing of the action). On the other hand, traditional speech act theory would encode an event as a speech action: an inform of the change.

Personally, I do not like the smushing together of events and actions in this way: each is a first class idea, not to be subordinated by the other. But they do seem to be very closely connected; almost two sides of a coin -- a yin to a yang.

So, we now have two fundamental 'things' being communicated: actions and events. Incidentally, an event can be used to communicate a real world effect - one of the cornerstones of the SOA Reference Model. And that is our invention for today.

Popular posts from this blog

Comments Should be Meaningless

This is something of a counterintuitive idea: Comments should be meaningless What, I hear you ask, are you talking about? Comments should communicate to the reader! At least that is the received conventional wisdom handed does over the last few centuries (decades at least). Well, certainly, if you are programming in Assembler, or C, then yes, comments should convey meaning because the programming language cannot So, conversely, as a comment on the programming language itself, anytime the programmer feels the imperative to write a meaningful comment it is because the language is not able to convey the intent of the programmer. I have already noticed that I write far fewer comments in my Java programs than in my C programs.  That is because Java is able to capture more of my meaning and comments would be superfluous. So, if a language were able to capture all of my intentions, I would never need to write a comment. Hence the title of this blog.

Hook, Line and Sinker

It is well documented that people’s #1 fear is speaking in public ! Effective and efficient public speaking is a whole topic in its own right; but a few simple tips might help to both improve your effectiveness and help to reduce the anxiety. You may be called on to talk about your work at very short notice; or you may have a week’s notice; and you may be required to give a formal slide show or just a brief verbal update. Many, if not most of the issues, are the same. The Hook Newspaper editors call the first paragraph of an article ‘the hook’. Its meant to hook you into reading the rest of the piece. On the other hand, the classical ‘say what you are going to say, say it, and say what you said’ approach gives people plenty of time to switch off. The hook may be playful, it may be controversial, but it must communicate why the listener should pay attention. The Line Its a conversation! Even if no one says anything they are listening and thinking; and maybe replying to you in their head...

Action at a distance

We are currently writing our first draft of the SOA Reference Architecture. Everyone is very busy doing their bit. My current section is on the Real World Effect of using a service. The RA is really an abstract architecture: we are not focusing on things like SOAP, or any of the other 60+ Web service specifications out there. We are trying to get at the essence of makes SOA special and how it can be made to work. It is a pretty basic aspect of services that we are trying to get something to happen: buy a book, get the weather forecast whatever. In other words: its action at a distance. I am communicating with you in the hope that we can get some mutual benefit. This already distinguishes SOA from the Web, whose basic abstraction is to acquire a representation of a resource will be rendered locally for human consumption. Actions are not inherently about representations, they are about changing the world - one book at a time. Action itself is a very difficult concept to get hold of. It ...