Work with Expressions

Use expressions to evaluate and perform calculations on data stored in data objects.

You can create expressions when configuring data associations and when configuring properties for user tasks.

Create Expressions

  • To create an expression, click Expression mode icon from the user task's properties field. This enables the expression mode and you can use the inline expression builder which gives auto-complete options for you to create and build your expression. You can use an expression to dynamically determine the task title, summary, due date, and assignees.

  • To create an expression while configuring data associations, enter the expression directly in the input or output fields of the data association editor. You can use the inline expression builder which gives auto-complete options for you to create and build your expression.

Key Points to Note About Expressions

  • Create expressions with data objects, operators, and functions. As soon as you put the cursor in the expression field, you get a list of suggested objects using which you can build the expression.
  • As you choose the object, related suggestions for the next level are displayed below the field. The suggestions are context sensitive. For example, suggestions displayed for a Title field will be different from that of a Due Date field.
  • Use Ctrl + Space to get more tabs and suggestions. A search field also displays that you can use to search data objects under the various tabs such as Process or Activity.
  • The type that is expected to be entered into the expression field is auto-suggested at the top right of the field.
  • If an expression is invalid, for example, if you type a number in a string field, an error message indicating the details of the error is displayed.
  • If the configured expression is too long, you can expand the field by using Ctrl + Enter keys.

Simple Expressions

Simple expressions are defined using a basic expression language and support. Generally simple expressions perform their calculations based on the data objects in your workflow. You can write expressions and conditions using the value of the data objects, but you can’t explicitly modify the value within the data object.

Here are some examples of expressions using operators:

  • totalAmount - discount

  • activationCount > 3

  • unitsSold <= 1200

Operator Precedence

Operator precedence defines the order in which the compiler evaluates operators. You can change operator precedence in an expression by using parentheses.

  • Addition, Subtraction

  • Multiplication, Division, Remainder

  • Plus, Minus

  • Less than, Greater than, Less than or equal to, Greater than or equal to

  • Equals, Not equals

  • Not

  • Conditional And

  • Conditional Or

The following sections lists Operators and Functions per type.

Unary

Operator Name Description
+ Plus Has no effect on the value of the numeric operand. Use it to explicitly indicate that a certain value is positive.
- Minus Negates an arithmetic expression.
! Not Logical complement operator. Negates the value of a Boolean expression.

Equality and Relational

Operator Name Description
= or == Equal to Returns true if the first operand is equal to the second operand
!= Not equal to Returns true if the first operand isn't equal to the second operand
> Greater than Returns true if the first operand is greater than the second operand
>= Greater than or equal to Returns true if the first operand is greater than or equal to the second operand
< Less than Returns true if the first operand is less than the second operand
<= Less than or equal to Returns true if the first operand is less than or equal to the second operand

Conditional

Operator Name Description
and Conditional And Returns true if both operands evaluate to true
or Conditional Or Returns true if either operand evaluates to true

String

Function/Operator Description Usage Expression Usage Result
+ String concatenation “pine” + “apple” “pineapple”
== Equals “apples” == “apples” true
!= Not equals “apples” != “oranges” true
> Greater than “word” > “work” false
>= Greater than or equals “work” >= “work” true
< Less than “word” < “work” true
<= Less than or equals “work” <= “work” true
contains Returns true if the first argument string contains the second argument string; otherwise returns false “caramel”.contains(“ram”) true
endsWith Returns true if the first argument string ends with the second argument string; otherwise returns false “immutable”.endsWith(“table”) true
length Returns the number of characters in a string “house”.length() 5
lowerCase Returns a string with all the characters in the argument converted to lower-case representation “Example”.lowerCase() “example”
startsWith Returns true if the first argument string starts with the second argument string, otherwise returns false “caramel”.startsWith(“car”) true
substring Returns the substring of the first argument starting at the position specified in the second argument and continuing to the end of the string “care”.substring(2) “are”
substring Returns the substring of the first argument starting at the position specified in the second argument with length specified in the third argument “care”.substring(1,3) “car”
upperCase Returns a string with all the characters in the argument converted to upper-case representation “Example”.upperCase() "EXAMPLE"
replaceAll Replaces each substring of this string that matches the given pattern with the given replacement. "care".replaceAll("e", "t") "cart"
indexOf Returns the index of the first occurrence of the specified substring, or -1 if there is no such occurrence. "care".indexOf("a") 2

Numeric

The following table includes operators for both Integer and Number.

Operator Description Usage Expression Usage Result
+ Addition 2 + 8 10
- Subtraction 7 – 4 3
* Multiplication 3 * 4 12
/ Division 3 / 2 1.5
% Remainder 3 % 2 1
== Equals 12 == 13 false
!= Not equals 12 != 13 true
> Greater than 15 > 16 false
>= Greater than or equals 15 >= 15 true
< Less than 12 < 10 false
<= Less than or equals 12 <= 12 true
abs Returns the absolute value of a number abs(- 6) 6

In addition to the above, the following specific operators are also available for Number.

Operator Description Usage Expression Usage Result
floor Returns the largest (closest to positive infinity) number that isn't greater than the argument and is an integer floor(5.60) 5
ceil Returns the smallest (closest to negative infinity) number that isn't less than the argument and is an integer ceil(5.60) 6
round Returns the number that is closest to the argument and is an integer round(5.60) 6

Date and Time

Date and Time types include Date, Time, and DateTime. All of them have the following operators.

Operator Description
+ Addition (valid only when the second argument is a duration)
- Subtraction (valid only when the second argument is a duration)
== Equals
!= Not equals
> Greater than
>= Greater than or equals
< Less than
<= Less than or equals
format Returns the formatted string of date-time using the provided format picture

In addition, Date, Time, and DateTime have specific operators as listed under each of them.

Date

Operator Description
year Returns a number representing the year component of the date-time argument.
month Returns a number representing the month component of the date-time argument.
day Returns a number representing the day component of the date-time argument.

Time

Operator Description
hours Returns a number between 0 and 23, both inclusive, representing the hours component of the date-time argument
minutes Returns a number between 0 and 59, both inclusive, representing the minutes component of the date-time argument.
seconds Returns a number between 0 and 59, both inclusive, representing the seconds component of the date-time argument.

DateTime

Operator Description
year Returns a number representing the year component of the date-time argument.
month Returns a number representing the month component of the date-time argument.
day Returns a number representing the day component of the date-time argument.
hours Returns a number between 0 and 23, both inclusive, representing the hours component of the date-time argument.
minutes Returns a number between 0 and 59, both inclusive, representing the minutes component of the date-time argument.
seconds Returns a number between 0 and 59, both inclusive, representing the seconds component of the date-time argument.
timezone Returns an interval value, representing the time offset from UTC.
toTimezone

Returns the date-time expressed in the time offset corresponding to the timezone ID provided.

You have the following options for specifying a timezone ID:

  • Provide a fixed offset from UTC/Greenwich, such as "-07:00".

    For example:

    • dateTimeDO.toTimezone("-07:00") returns 2002-11-30T17:20:00-07:00 when dateTimeDO is 2002-12-01T01:20:00+01:00

  • Specify a geographical region, which is an area where a specific set of rules for finding the offset from UTC/Greenwich apply. A geographical region is usually represented in the format "{area}/{city}", such as "Europe/Amsterdam" or "America/New_York".

    For example:

    • dateTimeDO.toTimezone("America/Los_Angeles") returns 2002-11-30T16:20:00-08:00 when dateTimeDO is 2002-12-01T01:20:00+01:00

Note:

You must include double quotation marks around the timezone ID value.

For more information about timezone IDs, see Class ZoneId in the Java Platform documentation.

Boolean

Operator Description Usage Expression Usage Result
== Equals true == true true
!= Not Equals true != false true
and Conditional — And true and false false
or Conditional — Or true or false true
not Logical complement operator, inverts the value of a Boolean expression. not true false

Duration

Operator Description
== Equals
!= Not equals
> Greater than
>= Greater than or equals
< Less than
<= Less than or equals