Identifiers
Identifiers can refer to the values of message headers and properties, but not to the message body. Identifiers are case-sensitive.
Basic Syntax
An identifier is a sequence of letters and digits, of any length, that begins with a letter. As in Java, the set of letters includes
_
(underscore) and
$
(dollar).
Illegal
Certain names are exceptions, which cannot be used as identifiers. In particular,
NULL
,
TRUE
,
FALSE
,
NOT
,
AND
,
OR
,
BETWEEN
,
LIKE
,
IN
,
IS
, and
ESCAPE
are defined to have special meaning in message selector syntax.
Value
Identifiers refer either to message header names or property names. The type of an identifier in a message selector corresponds to the type of the header or property value. If an identifier refers to a header or property that does not exist in a message, its value is
NULL
.