JMS Topic vs Queues

Question

I was wondering what is the difference between a JMS Queue and JMS Topic   ActiveMQ page says      Topics      In JMS a Topic implements publish and subscribe semantics  When you publish a message it goes to all the subscribers who are   interested - so zero to many subscribers will receive a copy of the   message  Only subscribers who had an active subscription at the time   the broker receives the message will get a copy of the message       Queues      A JMS Queue implements load balancer semantics  A single message will be received by exactly one consumer  If there are no   consumers available at the time the message is sent it will be kept   until a consumer is available that can process the message  If a   consumer receives a message and does not acknowledge it before closing   then the message will be redelivered to another consumer  A queue can   have many consumers with messages load balanced across the available   consumers    I want to have  something  what will send a copy of the message to each subscriber in the same sequence as that in which the message was received by the ActiveMQ broker   Any thoughts

User · Answer

If you have N consumers then   JMS Topics deliver messages to N of N JMS Queues deliver messages to 1 of N  You said you are  looking to have a  thing  that will send a copy of the message to each subscriber in the same sequence as that in which the message was received by the ActiveMQ broker    So you want to use a Topic in order that all N subscribers get a copy of the message

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Queues  Pros   Simple messaging pattern with a transparent communication flow Messages can be recovered by putting them back on the queue   Cons   Only one consumer can get the message Implies a coupling between producer and consumer as it   s an one-to-one relation   Topics  Pros   Multiple consumers can get a message Decoupling between producer and consumers  publish-and-subscribe pattern    Cons   More complicated communication flow A message cannot be recovered for a single listener

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Queue is JMS managed object used for holding messages waiting for subscribers to consume  When all subscribers consumed the message   message will be removed from queue   Topic is that all subscribers to a topic receive the same message when the message is published

User · Answer

That means a topic is appropriate  A queue means a message goes to one and only one possible subscriber  A topic goes to each and every subscriber

User · Answer

It is simple as that      Queues   Insert   Withdraw  send to single subscriber  1 1      Topics   Insert   Broadcast  send to all subscribers  1 n

User · Answer

TOPIC   topic is one to many communication     multipoint or publish subscribe  EX -imagine a publisher publishes the movie in the youtub then all its subscribers will gets notification     QUEVE  queve is one-to-one communication     Ex -When publish a request for recharge it will go to only one qreciever      always remember if request goto all qreceivers then multiple recharge happened so while developing analyze which is fit for a application

User · Answer

Topics are for the publisher-subscriber model  while queues are for point-to-point

User · Answer

As for the order preservation  see this ActiveMQ page   In short  order is preserved for single consumers  but with multiple consumers order of delivery is not guaranteed

User · Answer

A JMS topic is the type of destination in a 1-to-many model of distribution  The same published message is received by all consuming subscribers  You can also call this the  broadcast  model  You can think of a topic as the equivalent of a Subject in an Observer design pattern for distributed computing  Some JMS providers efficiently choose to implement this as UDP instead of TCP  For topic s the message delivery is  fire-and-forget  - if no one listens  the message just disappears  If that s not what you want  you can use  durable subscriptions    A JMS queue is a 1-to-1 destination of messages  The message is received by only one of the consuming receivers  please note  consistently using subscribers for  topic client s and receivers for queue client s avoids confusion   Messages sent to a queue are stored on disk or memory until someone picks it up or it expires  So queues  and durable subscriptions  need some active storage management  you need to think about slow consumers   In most environments  I would argue  topics are the better choice because you can always add additional components without having to change the architecture  Added components could be monitoring  logging  analytics  etc  You never know at the beginning of the project what the requirements will be like in 1 year  5 years  10 years  Change is inevitable  embrace it  -

[jms] JMS Topic vs Queues

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