Are Qt's signals and slots a form of publish-subscribe?

Question

I don't think I've seen this comparison anywhere, but would they be considered the same? If not, why not?

score 28 · Answer 1 · answered Oct 05 '13 at 16:29

28

They are very similar, but there is a little difference:

signals/slots implement the observer pattern, where the producer has a reference to its subscribers and is responsible of notifying them
the publish/subscribe paradigm inserts an additional mediator, i.e., the topic handler, which decouples producers and consumers (the producers does not know who will consume messages)

A main consequence is that in the p/s paradigm you can have multiple producers on the same topic.

This is (probably) the most cited article about p/s: The many faces of publish/subscribe

answered Oct 05 '13 at 16:29

tinito

2

+1 this is an important technical difference. In practice it means that in a p/s architecture you can replace one or more of the producers without the consumers being affected (because they don't reference the producer directly). This is great for testing consumer logic (replace a producer with a component that "stimulates" the consumers). Similarly, you can add or replace consumers, the producer doesn't care. Great for testing producer logic. – Oliver Jan 16 '14 at 20:34

score 1 · Accepted Answer · answered Mar 28 '12 at 08:50

1

publish subscribe is same as the signals and slots... check this...

answered Mar 28 '12 at 08:50

shofee

2 Answers2