A filter that matches properties on a message. This can be very useful, as the message properties represent all the meta information about the message from the underlying transport, so for a message received over HTTP, you can check for HTTP headers and so forth. The pattern should be expressed as a key/value pair, such as "propertyName=value". If you want to compare more than one property, you can use the logic filters for And, Or, and Not expressions. By default, the comparison is case sensitive, which you can override with the 'caseSensitive' property.