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Functions extend the power of Process Commander expressions. An
expression can contain calls to built-in functions, standard functions,
and custom functions you create.
Use the Function Builder to help you find the function you need. An
expression can contain many function calls, including nested calls.
B-1957 Use the keyword
<current> as a function argument to substitute the
current value of the target property in an expression.
This article relates to creating and using Java functions. For information about creating and using SQL functions in Report Definition rules, see About Report Definition Rules and Report Definition Rules - Using the Function Builder.
How to call
function rules
Use these three forms to call a function — a preferred
version that explicitly identifies the library and RuleSet, a short
form that may be useful in special situations, and a third form used
only within Java.
Preferred call syntax
The full syntax for calling a function identifies both the RuleSet
and the library:
@(RuleSet:libraryname).functionname(arg1,
arg2... argn)
For example:
@(MyInventory:Sort).CardType("Gold")
An alternative deprecated syntax, used before Version 04-01, is
still available:
lib(RuleSet:libraryname).functionname(arg1,
arg2... argn)
where RuleSet may be omitted (defaults to Pega-RULES),
and library may be omitted (defaults to default).
Short form call
You can use this notation to call a function rule:
@FunctionName(arg1, arg2... argn)
This syntax does not identify a RuleSet or a library for the
function. Your system may contain many functions that match the
function name. Process Commander uses your RuleSet list to find the
best one to execute, using the following algorithm:
- Collect a list of the Rule-Utility-Function rules
belonging to the RuleSets listed in the user's RuleSet list
that have the same name and same number of parameters.
- Exclude functions defined in any library named default.
(The use of the default library is deprecated.)
- If the list is empty, no such functions exist. The system
reports an error.
- If more than one such function exists (because the same name is
overloaded), select the best match by comparing the data types of
the parameters, using the promotion rules for Process Commander
data types.
- If the Rule-Utility-Function rule has not supplied
data types for its parameters or return value, use standard Java
promotion rules to match parameters. As a last resort, substitute
double for the preferred BigDecimal type
if necessary to get a match.
- If more than one function still exists in the list, report an
error.
Calling functions within a Java step
To call in a function within a Java step of an activity, use
standard Java conventions. Concatenate the RuleSet name with an
underscore and the library name, converting all letters to lowercase
and characters other than digits and letters to underscores. For
example, to call the CardType() function in the Sort library of the
MyInventory RuleSet, use: B-18409 exact case SDAS 3/21/06
myinventory_sort.CardType("Gold")
Process Commander constructs the Java class name for a
Rule-Utility-Library by concatenating the RuleSet name,
an underscore and the library name, with the resulting string
converted to lowercase and characters not valid in a Java identifier
translated to an underscore.
Built-in and
When() functions
Four functions are part of the expression language. All other names
following an at-sign are references to function rules,
instances of the Rule-Utility-Function rule type. An
expression can use any of these built-in functions:
Syntax
|
Description
|
|
These functions are part of the expression language. Their
names are reserved and cannot be overridden. These functions
may only be invoked using the preferred (‘@’)
syntax.
|
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@if( boolean expression, result1,
result2)
|
Evaluates the condition in parameter one and then, if
true, evaluates and returns parameter two, otherwise
evaluates and returns parameter three.
Equivalent to the Java ternary operator “?:.”
Only the one appropriate result parameter is evaluated.
|
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@and( e1, e2, ...)
|
Logical AND operation of the (arbitrary number of)
parameters (Evaluated left-to-right, stopping when the result
is known)
|
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@or( e1, e2, ...)
|
Logical OR operation of the (arbitrary number of)
parameters (Evaluated left-to-right, stopping when the result
is known)
|
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@java( code)
|
 The single parameter is
treated as Java code and inserted into the translated Java
stream without examination or modification.
|
| General purpose |
|
@when(name)
|
Evaluates a when condition rule in the context of the
primary page of the rule in which the expression appears. The
parameter can be an expression that evaluates to a text
value.
|
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@when(name, pagename)
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Evaluates the specified when condition rule using the
supplied ClipboardPage PublicAPI object (not a
page name) as the primary page for evaluation. Either
parameter can be an expression that evaluates to the correct
data type.
The
primary page for evaluation is supplied as a
ClipboardPage object, not a page name, so that
embedded pages (or pages whose name is not known) can be
evaluated.
|
You can use a Value List, Value Group, or
Page Group property as an argument to the @SUM(),
@MIN(), @MAX() and @AVERAGE().
Arithmetic
functions
These basic arithmetic functions are available.
Syntax
|
Description
|
| Scalar arithmetic |
|
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@abs(num)
|
Absolute value
|
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@sqr(num)
|
Square
|
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@sqrt(num)
|
Square root
|
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@exp(num)
|
Exponential
|
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@ceil(num)
|
Ceiling, least integer not greater than
|
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@floor(num)
|
Floor, greatest integer not less than
|
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@round(num)
|
Rounded to the nearest integer
|
| Aggregate arithmetic
|
|
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@sum(num1, num2)
|
Sum
|
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@max(num1, num2)
|
Maximum
|
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@min(num1, num2)
|
Minimum
|
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@mode(num1, num2)
|
Modal value Documentation is in progress
RETRACTED?
|
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@stddev(num1, num2)
|
Standard deviation Documentation is in progress
RETRACTED?
|
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@average(num1, num2)
|
Average
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You can use a Value List, Value Group, or
Page Group property as an argument to the @SUM(),
@MIN(), @MAX() and @AVERAGE().
Date and time
functions
The following functions operate with date and time values. A
DateTime Type property represents an instant in time
while Date and TimeofDay Types represent
values. Adding (the BigDecimal/double values corresponding to) a
Date and a TimeofDay together similarly
represents an instant in time, but in an unknown or arbitrary time
zone.
Syntax
|
Description
|
|
These Rule-Utility-Function rules are similar
to the corresponding functions in Excel.
|
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@date(year, month, day)
|
Returns a BigDecimal value (Process Commander
Date) corresponding to the int parameters
specified. The year is a four digit year, and is not adjusted
for a “base date.” The parameters are interpreted
leniently (as in Excel) through the use of the Java Calendar
class.
|
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@datevalue(string)
|
Returns a BigDecimal value (Process Commander
Date) corresponding to the parsed value of the
string specified. Only the date portion of the string is
considered.
|
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@day(double) @day(BigDecimal))
|
Returns the int value corresponding to the
day of the month (1 to 31) when the double parameter is
interpreted as a Process Commander Date.
|
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@month(double)
@month(BigDecimal)
|
Returns the Java int value corresponding to
the month of the year (0 to 11) when the double parameter is
interpreted as a Process Commander Date. The
corresponding Excel function also returns 0 to 11.
|
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@today()
@today(selection)
|
Returns the BigDecimal value (Process
Commander Date) corresponding to the current
date.
|
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@weekday(double)
@weekday(BigDecimal)
|
Returns the int value corresponding to the
day of the week (Sunday = 1 to Saturday = 7) when the double
parameter is interpreted as a Process Commander
Date.
|
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@year(double)
@year(BigDecimal)
|
Returns the int value corresponding to the
year when the double parameter is interpreted as a Process
Commander Date.
|
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@hour(double)
@hour(BigDecimal)
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Returns the Java int value corresponding to
the hour of the day (0 to 23) when the double parameter is
interpreted as a Process Commander Time of
Day.
|
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@minute(double)
@minute(BigDecimal)
|
Returns the Java int value corresponding to
the minute of the hour (0 to 59) when the double parameter is
interpreted as a Process Commander Time of
Day.
|
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@second(double)
@second(BigDecimal)
|
Returns the Java int value corresponding to
the second of the minute (0 to 59) when the double parameter
is interpreted as a Process Commander Time of
Day.
|
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@time(hour, minute, second)
|
Returns a BigDecimal value (Process Commander
Time of Day) corresponding to the int parameters
specified.
|
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@timevalue(string)
|
Returns a BigDecimal value (a Process
Commander Time of Day value) corresponding to
the parsed value of the string specified. Only the time
portion of the string is considered.
|
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The following functions facilitate conversion between
BigDecimal/double values derived from DateTime
properties and Date or Time of Day properties, the following
functions are provided.
Use these functions to adjust the double value resulting
from the sum of a Date and Time of
Day or the double value resulting from a
DateTime property into a (possibly different)
known time zone. The return type of these functions is the
same as the type of the first argument.
|
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@toGMT(double, zone)
@toGMT(BigDecimal, zone)
|
Returns a double/BigDecimal value (Process Commander
DateTime) in the GMT time zone corresponding to
the double value interpreted in the “zone” time
zone. Use to convert the sum of a Date and
Time of Day to a DateTime. If zone
is null, then the time zone of the requestor is used.
|
|
@toLOCAL(double, zone) NOT WORKING
11/17/06 OLSOK
@toLOCAL(BigDecimal, zone)
|
Returns a double/BigDecimal value that is the
result of treating the double value as a Process Commander
DateTime” (in the GMT time zone) and
converting it to the time zone. You can then treat the
resulting value as Date and Time of
Day values in the specified time zone. If zone is
null, then the time zone of the requestor session is
used.
For example, if bostonTime is a double that represents a
date and time in the Eastern Standard Time zone, you can find
the corresponding time in India by using:
toLOCAL(toGMT(bostonTime,
“EST”), “IST”)
|
Calling an
activity in an expression
The standard function callActivity(
) in the Pega-RULES Utilities library calls an
activity, but returns only void, not a value result. You can execute
an activity in an expression, but only for its side effects. MARIK
2/9/07 clinic. Identify the primary page, the activity, and the
parameter page. For example:
@Pega-RULES:Utilities.callActivity(pyWorkPage,
MyActivity,
tools.getParameterPage());
Calling an
overloaded function
Process Commander allows multiple function rules to be defined with
the same name, in the same RuleSet, version, and library, if they have
different signatures. The signature of a function is computed
automatically from the name, the position and data types of
parameters, and the return type. Functions that have multiple variants
are called overloaded.
When calling an overloaded function, you do not need to specify
which variant to use. The system determines which to use based on the
types and positions of parameters you supply.
For example, assume one function named Round is defined with two
variants:
- Round(double: d) — Returns an int by rounding the input
value d, a double
- Round(double: d, places: n) — Returns a double by
rounding the value to n decimal places
If your call includes two parameters, the system uses the second
variant.
About expressions
Functions in expressions