randomstringdeclaration

NAME
SYNOPSIS
DESCRIPTION
USAGE
EXAMPLE
COPYRIGHT
SEE ALSO

NAME

randomstringdeclaration − RWP*Load Simulator declare a random string

SYNOPSIS

randomstringdeclaration ::=
  [ private ] random string array identifier
  ( randomstringspec { , randomstringspec } )

randomstringspec ::=
  string expression

DESCRIPTION

Random string arrays are similar to string constants but they will randomly return one out of a list of strings. A random string array contains a number of strings that are given different weights, which are used to provide the probability of evaluating to that particular string.

When a named random string is being used in an expression one of the strings in the array will be used with the given probability.

Random strings can be declared with the private keyword which means they will be local to the file where they are defined; they cannot be declared locally.

USAGE

The random string is given a name that must followed by a parenthesized list of string constants with weights. Weights are double values, they cannot be negative and the sum of them must be positive. The weights will be scaled to probabilities in the range [0;1] and when you use the random string, one of the strings will be returned with that probability. A string with weight zero will never be returned and there must be at least one string in the list.

Random strings cannot be used as the variable for the bind attribute of a SQL statement.

EXAMPLE

Here is a short example:

random string array maybe ( "yes" 20, "no" 70, "maybe" 10);
printline maybe, maybe, maybe, maybe, maybe, maybe, maybe;

This declares the variable maybe as a random string array with three entries. Whenever maybe is used in a concatenation, one of the three entries will be returned, and each entry will be returned with a certain probability. In this case, the weights are given as 20, 70 and 10, and because the sum of these is 100, these values effectively are percentages. A few executions of this might give:

no no maybe no no no no
no yes no no no no no
no no yes maybe no yes yes