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Diffstat (limited to 'qpid/cpp/examples/old_api/xml-exchange/README.txt')
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diff --git a/qpid/cpp/examples/old_api/xml-exchange/README.txt b/qpid/cpp/examples/old_api/xml-exchange/README.txt new file mode 100644 index 0000000000..85caebe352 --- /dev/null +++ b/qpid/cpp/examples/old_api/xml-exchange/README.txt @@ -0,0 +1,53 @@ +This example shows how to program a simple application +using the XML Exchange. + +[Note: The XML Exchange is not a standard AMQP exchange type. To run +this example you need to have a broker that has support for the xml +exchange. If you are compiling the broker from source please refer to +the INSTALL notes from qpid.] + +To run the example, execute the programs in the +following order: + +1 ./declare_queues +2 ./listener +3 ./message_producer (in a separate window) + +The XML Exchange must be explicitly declared. Bindings +are established using queries in XQuery. These queries +can reference message content, message application +properties (which are declared as external variables +in the XQuery), or both. + +Once this is done, message producers publish to the +exchange using the exchange name and a routing key, +just as for other exchange types. Message consumers +read from the queues to which messages are routed. +If a message does not have XML content, or is +missing message application properties needed by +the query, the query is not routed. + +Queries can use message application headers to +provide functionality similar to JMS selectors. +If a query does not use the content of a message, +the message content is not parsed, and need not +be XML. + +The XQuery processor, XQilla, does path-based +document projection, so once the portion of +a document needed to evaluate a query has +been read, it stops parsing the document. +Suppose a long document has a header section. +You can indicate in the query that only +one header section needs to be queried, +and there is no need to parse the entire +document to see if there are further header +sections, using a path like this: + +./message/header[1]/date + +If you used a path like this, all children +of the message element would be read to +see if there are further headers: + +./message/header/date |