Introduction
Variables are assigned constant values and expressions. This applies to:
- JS7 - Job Resources
- JS7 - Job Environment Variables
- JS7 - Order Variables
- Node Arguments
- Job Arguments
Expressions are a means to dynamically calculate values for variables. Consider that names of variables are case-sensitive.
Example:
true
1
"some string"
$variable
$returnCode <= 3
$number + 1
Data Types
Boolean
The following constant values are supported: true,
false
Example:
Expression | true |
---|---|
JSON | "var": true |
Expression | false |
---|---|
JSON | "var": false |
String
Strings are written in double quotes. The control characters \t
(tab), \r
(CR) and \n
(NL) are literally written. To suppress its special meaning the $ character is written \$
. No other characters are allowed to follow the \ escape character.
Example:
Expression |
|
---|---|
JSON | "var": "\"some value\"" |
Expression |
|
---|---|
JSON | "var": "\"\\t means the TAB control character\"" |
Expression |
|
---|---|
JSON |
|
Expression |
|
---|---|
JSON |
|
Expression |
|
---|---|
JSON | "var": "\"\\$ means the literal character\"" |
Number
Numeric constants are implemented as Java BigDecimal
values and allow integer and long values to be specified.
Example:
Expression |
|
---|---|
JSON | "var": 1 |
Operators
Comparison Operators
The operators <
, <=
, ==
, !=
, >=
, >
are supported.
The result of a comparison is the Boolean
data type. Comparisons are available for strings and numbers. Both sides of a comparison have to use the same data type.
Should this rule not be considered and should e.g. a number be compared to a string then an Order will fail.
Example:
Expression |
|
---|---|
JSON | "var": "$var >= 199" |
Arithmetic Operators
Addition and Subtraction of two numbers with: +, -
Example:
Expression |
|
---|---|
JSON | "var": 1 + 1 |
Expression |
|
---|---|
JSON | "var": 100 - 210 |
String Operators
Concatenation of two strings with the ++
operator.
Should operands of type Boolean or Number be used then they are converted to String.
Example:
Expression |
|
---|---|
JSON | "var": "\"abc\" ++ \"def\"" |
Conversion
Convert to Number
If a value of a variable with String data type represents a number then it can be converted. Otherwise an error is raised and the affected order fails.
Example:
Expression |
|
---|---|
JSON | "var": "\"123\".toNumber" |
Convert to String
Values of the Number data type can be converted to String.
Example:
Expression |
|
---|---|
JSON | "var": "123.toString" |
Reading Variables
Referencing Variables
The syntax $VARIABLE
, ${VARIABLE}
is used to read the value of a variable.
Similar to a number of Unix shells a variable can be recalled with $ or with ${}.
If the variable is unknown then an error is raised and the affected Order will fail.
Variable Function
Variables can be retrieved using the function
variable( NAME, label=LABEL, job=JOB, default=DEFAULT )
NAME
is a string expression for the name of the variable.label=LABEL
(optional) is the label of an instruction for which the variable is recalled. Consider that the label is not quoted. Example:label=A
.job=JOB
(optional) is the name of a job for which the variable is recalled. Consider that the job name is not quoted. Example:job=MYJOB
.default=DEFAULT
(optional) specifies a default value should the variable not exist.
Consider that a call to the variable
function will fail if the variable is unknown and no default value is specified.
Built-in Variables
Built-in variables are available at the following scopes:
Workflow
$js7WorkflowPath
- The unique name of a workflow. Consider that a
$js7WorkflowPosition
- The position of an order in the workflow.
$js7Label
- The label of the current instruction for which an order is executed.
$js7OrderId
- The order identifier.
$js7ControllerId
- The Controller's identifier.
Job
$js7JobName
- The name of the current job for which an order is executed.
$epochMilli
- The number of milliseconds since January 1st 1970 until the start of the current job for which an order is executed.
$returnCode
- The numeric exit code of the current job for which an order is executed.
Build-in Functions
now( format='yyyy-MM-dd hh:mm:ss', timezone='Europe/Berlin' )
- The job start date. This date can be formatted using Java data qualifiers. Optionally a time zone can be specified, otherwise the UTC time zone is used.
scheduledOrEmpty( format='yyyy-MM-dd hh:mm:ss', timezone='Europe/Berlin' )
- The date for which an orders is scheduled.