Let's use qpid-config to create a queue and a topic.

$ qpid-config add queue my-queue
$ qpid-config add exchange topic my-topic
	

We can now use the address specified to drain to assert that it is of a particular type:

$ ./drain 'my-queue; {assert: always, node:{ type: queue }}'
$ ./drain 'my-queue; {assert: always, node:{ type: topic }}'
2010-04-20 17:30:46 warning Exception received from broker: not-found: not-found: Exchange not found: my-queue (../../src/qpid/broker/ExchangeRegistry.cpp:92) [caused by 2 \x07:\x01]
Exchange my-queue does not exist
	

The first attempt passed without error as my-queue is indeed a queue. The second attempt however failed; my-queue is not a topic.

We can do the same thing for my-topic:

$ ./drain 'my-topic; {assert: always, node:{ type: topic }}'
$ ./drain 'my-topic; {assert: always, node:{ type: queue }}'
2010-04-20 17:31:01 warning Exception received from broker: not-found: not-found: Queue not found: my-topic (../../src/qpid/broker/SessionAdapter.cpp:754) [caused by 1 \x08:\x01]
Queue my-topic does not exist
	

First Window:

$ ./drain -t 30 "xoxox ; {create: always}"

Now we can send messages to this queue:

Second Window:

$ ./spout "xoxox ; {create: always}"

Returning to the first window, we see that drain has received this message:

Message(properties={spout-id:1a1a3842-1a8b-4f88-8940-b4096e615a7d:0}, content='')

Let's use the browse mode to receive messages without removing them from the queue. First we send three messages to the queue:

$ ./spout my-queue --content one
$ ./spout my-queue --content two
$ ./spout my-queue --content three
        

Now we use drain to get those messages, using the browse option:

$ ./drain 'my-queue; {mode: browse}'
Message(properties={spout-id:fbb93f30-0e82-4b6d-8c1d-be60eb132530:0}, content='one')
Message(properties={spout-id:ab9e7c31-19b0-4455-8976-34abe83edc5f:0}, content='two')
Message(properties={spout-id:ea75d64d-ea37-47f9-96a9-d38e01c97925:0}, content='three')
        

We can confirm the messages are still on the queue by repeating the drain:

$ ./drain 'my-queue; {mode: browse}'
Message(properties={spout-id:fbb93f30-0e82-4b6d-8c1d-be60eb132530:0}, content='one')
Message(properties={spout-id:ab9e7c31-19b0-4455-8976-34abe83edc5f:0}, content='two')
Message(properties={spout-id:ea75d64d-ea37-47f9-96a9-d38e01c97925:0}, content='three')
        

This example uses an x-binding that contains queries, which filter based on the content of XML messages. Here is an XQuery that we will use in this example:

	  
let $w := ./weather 
return $w/station = 'Raleigh-Durham International Airport (KRDU)' 
   and $w/temperature_f > 50
   and $w/temperature_f - $w/dewpoint > 5
   and $w/wind_speed_mph > 7
   and $w/wind_speed_mph < 20 
	

We can specify this query in an x-binding to listen to messages that meet the criteria specified by the query:

First Window:

$ ./drain -f "xml; {link:{x-bindings:[{key:'weather', 
arguments:{xquery:\"$(cat rdu.xquery )\"}}]}}"
	

In another window, let's create an XML message that meets the criteria in the query, and place it in the file rdu.xml:

<weather>
  <station>Raleigh-Durham International Airport (KRDU)</station>
  <wind_speed_mph>16</wind_speed_mph>
  <temperature_f>70</temperature_f>
  <dewpoint>35</dewpoint>
</weather>
	

Now let's use spout to send this message to the XML exchange:

Second Window:

spout --content "$(cat rdu.xml)" xml/weather
	

Returning to the first window, we see that the message has been received:

$ ./drain -f "xml; {link:{x-bindings:[{exchange:'xml', key:'weather', arguments:{xquery:\"$(cat rdu.xquery )\"}}]}}"
Message(properties={qpid.subject:weather, spout-id:31c431de-593f-4bec-a3dd-29717bd945d3:0}, 
content='<weather>
  <station>Raleigh-Durham International Airport (KRDU)</station>
  <wind_speed_mph>16</wind_speed_mph>
  <temperature_f>40</temperature_f>
  <dewpoint>35</dewpoint>
</weather>')