检查Solace中是否存在队列

Question

I'm using Java API to connect to Solace, provision queues and subscribe them to topics. In case those queues are already exists I would like to avoid doing it again. Using Java API is it possible to check if particular queue exists and which topics are mapped to that queue?

Answer 1

The best way to do this is to attempt to provision, and make use of the JCSMPSession.FLAG_IGNORE_ALREADY_EXISTS and JCSMPProperties.IGNORE_DUPLICATE_SUBSCRIPTION_ERROR properties.

Here's an quick example:

JCSMPProperties properties = new JCSMPProperties();
properties.setProperty(JCSMPProperties.HOST, "your_router_dns_name");
properties.setProperty(JCSMPProperties.USERNAME, "default");
properties.setBooleanProperty(JCSMPProperties.IGNORE_DUPLICATE_SUBSCRIPTION_ERROR, true);

JCSMPSession session =  JCSMPFactory.onlyInstance().createSession(properties);

Queue queue = JCSMPFactory.onlyInstance().createQueue("myqueue");
EndpointProperties props = new EndpointProperties(); // default properties, modify as needed
session.provision(queue, props, JCSMPSession.FLAG_IGNORE_ALREADY_EXISTS);

Topic topic = JCSMPFactory.onlyInstance().createTopic("my/topic");
session.addSubscription(queue, topic, JCSMPSession.WAIT_FOR_CONFIRM);

Note that there's no actual method to verify if the queue and topic subscriptions exist using the API. If absolutely necessary, you can make use of SEMP over message bus to execute show commands, but this is pretty unwieldy.