DLQ rules table conventions

The syntax, structure and contents of the dead-letter queue handler rules table must adhere to these conventions.

The rules table must adhere to the following conventions:

• A rules table must contain at least one rule.
• Keywords can occur in any order.
• A keyword can be included only once in any rule.
• Keywords are not case-sensitive.
• A keyword and its parameter value must be separated from other keywords by at least one blank or comma.
• There can be any number of blanks at the beginning or end of a rule, and between keywords, punctuation, and values.
• Each rule must begin on a new line.
• On Windows systems, the last rule in the table must end with a carriage return/line feed character. We can achieve this by ensuring that you press the Enter key at the end of the rule, so that the last line of the table is a blank line.
• For reasons of portability, the significant length of a line must not be greater than 72 characters.
• Use the plus sign (+) as the last nonblank character on a line to indicate that the rule continues from the first nonblank character in the next line. Use the minus sign (-) as the last nonblank character on a line to indicate that the rule continues from the start of the next line. Continuation characters can occur within keywords and parameters.

  For example:

  APPLNAME('ABC+
  D')
  

  results in 'ABCD', and

  APPLNAME('ABC-
  D')
  

  results in 'ABC D'.

• Comment lines, which begin with an asterisk (*), can occur anywhere in the rules table.
• Blank lines are ignored.
• Each entry in the DLQ handler rules table comprises one or more keywords and their associated parameters. The parameters must follow these syntax rules:
  • Each parameter value must include at least one significant character. The delimiting single quotation marks in values that are enclosed in quotation marks are not considered to be significant. For example, these parameters are valid:

    	FORMAT('ABC')	3 significant characters
    	FORMAT(ABC)	3 significant characters
    	FORMAT('A')	1 significant character
    	FORMAT(A)	1 significant character
    	FORMAT(' ')	1 significant character

    These parameters are invalid because they contain no significant characters:

    	FORMAT('')
    	FORMAT( )
    	FORMAT()
    	FORMAT

  • Wildcard characters are supported. We can use the question mark (?) instead of any single character, except a trailing blank; we can use the asterisk (*) instead of zero or more adjacent characters. The asterisk (*) and the question mark (?) are always interpreted as wildcard characters in parameter values.
  • Wildcard characters cannot be included in the parameters of these keywords: ACTION, HEADER, RETRY, FWDQ, FWDQM, and PUTAUT.
  • Trailing blanks in parameter values, and in the corresponding fields in the message on the DLQ, are not significant when performing wildcard matches. However, leading and embedded blanks within strings that are enclosed in single quotation marks are significant to wildcard matches.
  • Numeric parameters cannot include the question mark (?) wildcard character. We can use the asterisk (*) instead of an entire numeric parameter, but not as part of a numeric parameter. For example, these are valid numeric parameters:

    	MSGTYPE(2)	Only reply messages are eligible
    	MSGTYPE(*)	Any message type is eligible
    	MSGTYPE('*')	Any message type is eligible

    However, MSGTYPE('2*') is not valid, because it includes an asterisk (*) as part of a numeric parameter.
  • Numeric parameters must be in the range 0-999 999 999. If the parameter value is in this range, it is accepted, even if it is not currently valid in the field to which the keyword relates. We can use symbolic names for numeric parameters.
  • If a string value is shorter than the field in the MQDLH or MQMD to which the keyword relates, the value is padded with blanks to the length of the field. If the value, excluding asterisks, is longer than the field, an error is diagnosed. For example, these are all valid string values for an 8 character field:

    	'ABCDEFGH'	8 characters
    	'A*C*E*G*I'	5 characters excluding asterisks
    	'*A*C*E*G*I*K*M*O*'	8 characters excluding asterisks

  • Enclose strings that contain blanks, lowercase characters, or special characters other than period (.), forward slash (?), underscore (_), and percent sign (%) in single quotation marks. Lowercase characters not enclosed in single quotation marks are folded to uppercase. If the string includes a quotation, use two single quotation marks to denote both the beginning and the end of the quotation. When the length of the string is calculated, each occurrence of double quotation marks is counted as a single character.