thanks for the examples. just wanted to make sure if my understanding is correct: * is to match any name, including empty name; > is to match any name (not for empty?) and hierarchy.
So a.* means 'a.' followed by one or zero hierarchy. a.> means 'a.' followed by one or more levels of hierarchy. am I correct ? rgds, canal ________________________________ From: Sebastian Rodriguez <srodrig...@gmail.com> To: users@activemq.apache.org Sent: Thu, April 15, 2010 1:38:10 PM Subject: Re: Topic Inheritance Hi canal, Yes, car.ford.> and car.ford.* will receive the same messages. The difference is that for example you want to receive all the messages concerning truck, *.*.truck will make the trick :) For the difference between * and > maybe this other example will help you understand: a.b.c a.b.d a.e.c - if you subscribe to a.> you will receive everything sent to "a.b.c", "a.b.d", "a.e.c", "a.b", "a.e", "a" this will be equivalent as a.*.* - if you subscribe to a.b.> you will receive messages sent to "a.b.c", "a.b.d", "a.b" this is equivalent of subscribing to a.b.* - The problem comes if, let's say, you want to subscribe to "everything that ends with c" you will have to subscribe to "*.*.c" This is not translatable to a ">" expression. You might ask yourself: then, why use the ">" if i can always translate it to "*" expression. Well, sometimes you simply dont know the depth of the childs, and it's more error proof. I would rather subscribe to "lambda.>" than to "lambda.*.*.*.*.*" for eg Hope this has clarified your doubts! On 15 April 2010 12:20, go canal <goca...@yahoo.com> wrote: > this solves my chat room use case also, thanks. I did not realize this > feature, did not remember JMS has this. > > A question wrt > and *, not very clear about these two: if I have > car.ford.suv, car.ford.truck > > are these two the same: > car.ford.> > car.ford.* > > rgds, > canal > > > > > ________________________________ > From: Rob Davies <rajdav...@gmail.com> > To: users@activemq.apache.org > Sent: Thu, April 15, 2010 8:51:50 AM > Subject: Re: Topic Inheritance > > Yes - ActiveMQ supports destination hierarchies - a '.' dot notation > denotes an element in the name. > To extend your example - say you had models too - to subscribe to all Ford > cars - you would use '>'. e.g. car.ford.> > You can use the '*' to subscribe to everything for > So to subscribe to cars - you would subscribe to the topic car.> > To subscribe to all cars of type mondeo - you would subscribe to > car.*.modeo - or *.*.mondeo > > Hope that makes sense ? > On 14 Apr 2010, at 17:35, carlosfocker wrote: > > > > > Does ActiveMQ allow for topics to have parent topics? For example, a > parent > > topic Car might have two child topics called Ford and Nissan. If a > > publisher publishes a message to the Car topic, both Ford and Nissan > > subscribers would receive the message. If a message is published to the > > Nissan topic, only Nissan topic subscribers would receive the message. > > -- > > View this message in context: > http://old.nabble.com/Topic-Inheritance-tp28245081p28245081.html > > Sent from the ActiveMQ - User mailing list archive at Nabble.com. > > > > > > -- Sebastien Rodriguez
