Expressions in Parameters
An expression in a parameter definition can take one the following values:
An explicit value; for example, 1000000
Another parameter; for example, a parameter called bodDestPort
A mathematical expression that can include a combination of:
Parameters
Numbers—Integers and floating point numbers
Strings
IPv4 addresses
Ranges of numbers, strings, and addresses
Lists of values, such as lists of protocols
Maps—List of pairs of attributes and corresponding values
One keyword, not
Separators
Operators
For example, x == 1 ? rate : 2*rate
The syntax for mathematical expressions is based primarily on Java syntax, although a few items use a proprietary syntax. When evaluating mathematical expressions, the SRC software:
Follows a defined order for the precedence of operators.
Performs all evaluations in long integer format until it finds an argument or result that is in Java floating point number format. Subsequently, the software performs evaluations in Java double floating point number format.
Evaluates only subordinate expressions that meet the conditions for evaluation.
Evaluates only subordinate expressions that contain numbers and not parameters.
Stops the evaluation and substitutes the partial evaluation if an argument in double floating number format becomes an argument to an operator that takes only integers.
Behaves in the same way as a Java evaluation if intermediate evaluations exceed or fall below the long integer range or the double floating point number range.
Follows the Java rules for raising exceptions. For example, the software raises an exception if:
An evaluation involves a division by zero.
Literal numbers exceed the long integer limit or the double floating point number limit.
The following sections describe how to format the items that you can use in an expression.
Specifying Parameter Names
Observe the following rules when you are specifying parameter names:
Enter a string of alphanumeric characters starting with a letter.
Do not use spaces or special characters. For example, do not use the at sign (@) in a parameter name.
You can use the underscore (_) and the dollar sign ($). Use the dollar sign to encode special characters by entering the Unicode equivalent of the character in hexadecimal format after the dollar sign. For example, use $0040 to encode the at sign (@).
Formatting Numbers
Observe the following rules when you are formatting numbers:
Enter a digit after the decimal point in a floating point number. For example, you can use the number 4.0, but not the number 4.
Do not enter characters that specify the type of number after that number. For example, do not enter the character L after a number to indicate that the number is a long integer.
Formatting Strings
Use Java syntax for strings; enclose strings in double quotation marks.
Example—“engineering”
Observe the following rules when you are formatting strings:
Do not use octal escape sequences in strings. For example, do not use the escape sequence \137 in a string.
Do not use Unicode escape sequences. For example, do not use the escape sequence \u80A6 in a string.
Using IPv4 Addresses
Use the following format for IP addresses:
Single quotation marks around an item indicate that it represents an address; however, for IPv4 addresses, the quotation marks are optional.
Specifying Ranges
To specify a range of numbers, strings, and addresses, use two dots between the arguments.
Formatting Lists
To specify a list of values, enclose a set of subordinate expressions separated by commas in a pair of square brackets.
Formatting Maps
Maps are used to specify values that have optional and interdependent attributes. For example, when you define an application object through the Enterprise Manager portal, you can select a number of attributes and specify particular values for them. Depending on the value of the attribute, other attributes are possible or required.
To format a map, specify a list of pairs of attributes and corresponding values. Separate the pairs with commas, and enclose the list in curly brackets (braces).
Using Keywords
The SRC software ignores all Java keywords in substitutions, so that you can use Java keywords for identifiers such as variable names, function names, and attribute names in maps. The SRC software accepts one keyword, not, which is used to indicate conditions that do not match a specified value. For more information about the not keyword.
Using Separators
You cannot use a dot (.) as a separator. You can use other Java separators in the ways that Java supports.
Using Operators
Table 1 shows the operations and corresponding operators that the SRC software supports for substitutions. Most of the operators are Java operators, although a few operators are proprietary. You cannot use Java operators that do not appear in this table.
Table 1: Operations That You Can Use in Expressions
Operation  Operator  Number of Arguments  Result If Different from Java Conventions  Conditions for Evaluation  Example 

Bitwise AND of the arguments  &  Two  Both arguments must be integers  234567 & 876543  
Bitwise exclusive OR of the arguments  ^  Two  Both arguments must be integers  234567 ^ 876543  
Bitwise inclusive OR of the arguments    Two  Both arguments must be integers  234567  876543  
Bitwise negation of the argument  ~  One  Argument must be an integer  –234567  
Difference between two arguments  –  Two  Both arguments must be numbers  876543 – 234567  
Division of the first argument by the second argument  /  Two  Result of operation in double format  Both arguments must be numbers  589 / 756 
Equal  ==  Two  Nonzero number if the arguments are equal  Both arguments must be numbers  rate==5 
Greater than  >  Two  Nonzero integer if the first argument is greater than the second argument  Both arguments must be numbers  rate>5 
Greater than or equal to  >=  Two  Nonzero integer if the first argument is greater than or equal to the second argument  Both arguments must be numbers  rate>=5 
If... then... else... operation  ?:  Three  If the first argument is nonzero, then the result is the second argument, else the result is the third argument  First argument must be a number  “ x == 1 ? rate : 2*rate” 
Less than  <  Two  Nonzero integer if the first argument is less than the second argument  Both arguments must be numbers  rate<5 
Less than or equal to  <=  Two  Nonzero integer if the first argument is less than or equal to the second argument  Both arguments must be numbers  rate<=5 
Logical AND  &&  Two  Nonzero integer if both the arguments are nonzero  Both arguments must be numbers  x == 1 && y >= 5 
Logical NOT  !()  One  Zero if the argument is nonzero  All arguments must be numbers  ! x ==y 
Logical OR    Two  Nonzero integer if at least one of the arguments is nonzero  Both arguments must be numbers  x==1  y>=5 
Maximum of the arguments, max() = –infinity  max()  Zero or more  All arguments must be numbers  max (1, 3, 2, 4)  
Minimum of the arguments, min() = +infinity  min()  Zero or more  All arguments must be numbers  min (1, 3, 2, 4)  
Negation  –  One  Argument must be a number  –5  
Not equal  !=  Two  Nonzero integer if the arguments are not equal  Both arguments must be numbers  rate !=5 
Not match  not  One  None – expressions with this operator cannot be evaluated  not 192.0.2.1  
Product of the arguments  *  Two  Both arguments must be numbers  rate*2  
Raise the first argument to the power of the second argument  **  Two  Both arguments must be numbers  2**16  
Range from the first argument to the second argument  ..  Two  None—expressions with this operator cannot be evaluated  0..49  
Remainder of division of the first argument by the second argument  %  Two  Both arguments must be integers  5%2  
Round off the argument to the closest number  round()  One  Integer closest to the argument  Argument must be numbers  round(986532.654) 
Round the argument down  floor()  One  Biggest integer less than or equal to the argument  Argument must be numbers  floor (986532.654) 
Round the argument up  ceiling()  One  Smallest integer greater than or equal to the argument  Argument must be numbers  ceiling (986532.654) 
Shift the first argument left by the number of bits in the second argument  <<  Two  Both arguments must be integers  986532 << 2  
Shift the first argument right by the number of bits in the second argument  >>  Two  Both arguments must be integers  986532 >>2  
Sum of the arguments  +  One or two  Both arguments must be numbers  876 + 345 +855 
The precedence of the Java operators is the same as the precedence in Java; if you are unsure of the precedence of the operators, you can use parentheses to ensure that the software evaluates expressions in the desired way. For example, the following logical OR expression does not need parentheses.
You can, however, include parentheses as follows:
The following list shows the precedence of the operators from lowest precedence to highest precedence:
not
..
?:

&&

^
&
==, !=
<,>,<=,>=
<<,>>
+,– (binary)
*,/,%
**
+,– (unary)
~,!