A JMS Message Selector is a string in
a subset of SQL-92 syntax that allows a client to specify by message
header or property the messages it's interested in. Only messages whose
headers or properties match the selector are delivered. For example, you
can specify that your message-driven bean receive only those
messages whose NewsType property is set to the value "Opinion" or "Sports"
by entering this selector:
NewsType = 'Opinion' OR NewsType = 'Sports'