This section describes expression language functions related to retrieving data from contexts and manipulating them.

Function

Description

Result Type

Backend Support

Frontend Support

actionAvailable(String context, String action [, String schema])

Evaluates whether a given action is available within a specified context. Returns true if the action identified by the action parameter is available in the context indicated by the context parameter to the caller of the actionAvailable function. If the action is not available, it returns false.

Boolean

Yes

Yes

available(String context [, String schema])

Returns true if context with path context exists and is available to the caller.

Boolean

Yes

Yes

callFunction(String context, String function, Object parameter1, Object parameter2, ...)

Calls a function named function of a context with path context and returns its output. Function's input Data Table is constructed from array of parameters (parameter1, parameter2, ...). Rules used to fill table with data are covered here.

DataTable

Yes

Yes

callFunctionEx(String context, String function, DataTable parameters [, String schema])

Similarly to callFunction(...) calls a function named function of a context with path context and returns its output. Function parameters are represented by the parameters Data Table.

DataTable

Yes

Yes

dc([String schema])

Returns the path of the default context defined during expression evaluation.

String

Yes

Yes

Another way to get path of default context is using {.:} reference.

dr()

Returns default row defined during expression evaluation.

Integer

Yes

Yes

dt()

Returns default table defined during expression evaluation.

DataTable

Yes

Yes

Another way to get default table is using {} reference.

eventAvailable(String context, String event [, String schema])

Returns true if context with path specified by context argument has variable specified by event argument and this event is available to the caller.

Boolean

Yes

Yes

eventFormat(String context, String event [, String schema [, Boolean asTable]])

Returns string representation of event format or null if context/event is not available or event's format is dynamic.

By default, uses invisible separators encoding mode to encode the table as a string. To return the result as a Data Table, set asTable to True.

Note that when evaluating expressions in the Web UI Expression Builder, the eventFormat function must be evaluated on the server when using the asTable parameter.

String

Yes

Yes

eventGroup(String context, String event [, String schema])

Returns name of a group the event belongs to or null if it doesn’t belong to any group.

String

Yes

No

fireEvent(String context, String event, Integer level, Object parameter1, Object parameter2, ...)

Fires event named event in context. Uses specified level or event's default level if level parameter is null. Event level codes are described here.

If just one parameter is provided and it's of Data Table type, this table will be used as event's data table, data table format of this parameter must be equal as event data table format. Otherwise Data Table representing event's data is constructed from array of parameters (parameter1, parameter2, ...). Rules used to fill table with data are covered here.

The function returns an ID of generated event or null if event generation was suppressed by the system.

Long

Yes

Yes

The fireEvent() function will only work in an expression that is evaluated inside Iotellect Server. Expressions that are evaluated in Iotellect Client or Agent will not cause generation of server-side events.

fireEventEx(String context, String event, Integer level, DataTable value [, String schema])

Works similarly to fireEvent(), but accepts event data as a data table and allows to specify schema.

fullDescription(String context [, String delimiter])

Returns a full description of the specified context, i.e. descriptions of all parent contexts separated by delimiter string. The delimiter is "-" by default.

String

Yes

Yes

functionAvailable(String context, String function [, String schema])

Returns true if context with path specified by context argument has function specified by function argument and this function is available to the caller.

Boolean

Yes

Yes

functionGroup(String context, String function[, String schema])

Returns name of a group the function belongs to or null if it doesn’t belong to any group.

String

Yes

No

functionInputFormat(String context, String function [, String schema [, Boolean asTable]])

Returns string representation of function input format or null if context/function is not available or function's input format is dynamic.

By default, uses invisible separators encoding mode to encode the table as a string. To return the result as a Data Table, set asTable to True.

Note that when evaluating expressions in the Web UI Expression Builder, the functionInputFormat function must be evaluated on the server when using the asTable parameter.

String

Yes

Yes

functionOutputFormat(String context, String function [, String schema [, Boolean asTable]])

Returns string representation of function output format or null if context/function is not available or function's output format is dynamic.

By default, uses invisible separators encoding mode to encode the table as a string. To return the result as a Data Table, set asTable to True.

Note that when evaluating expressions in the Web UI Expression Builder, the functionOutputFormat function must be evaluated on the server when using the asTable parameter.

String

Yes

Yes

getVariable(String context, String variable [, String schema])

Gets a variable named variable from a context with path context and returns its value.

DataTable

Yes

Yes

setVariable(String context, String variable, Object parameter1, Object parameter2, ...)

Sets a variable named variable of a context with path context. If just one parameter is provided and it's of Data Table type, this table will be used as a new variable value. Otherwise Data Table representing new variable value is constructed from array of parameters (parameter1, parameter2, ...). Rules used to fill table with data are covered here.

Null

Yes

Yes

setVariableEx(String context, String variable, DataTable value [, String schema])

Similar to setVariable(...). Sets a variable named variable of a context with path context. The value parameter is a Data Table representing new value for the variable.

Null

Yes

Yes

setVariableField(String context, String variable, String field, Integer record, Object value)

Sets a cell value in a variable named variable of a context with path context. The cell is specified by field and record parameters.

Null

Yes

Yes

setVariableRecord(String context, String variable, Integer record, Object parameter1, Object parameter2, ...)

Sets a record in a variable named variable of a context with path context. The record is specified by record parameter. Other parameters are used for constructing the record.

Null

Yes

Yes

variableAvailable(String context, String variable [, String schema])

Returns true if context with path specified by context argument has variable specified by variable argument and this variable is available to the caller.

Boolean

Yes

Yes

variableFormat(String context, String variable [, String schema [, Boolean asTable]])

Returns string representation of variable format or null if context/variable is not available or variable's format is dynamic.

By default, uses invisible separators encoding mode to encode the table as a string. To return the result as a Data Table, set asTable to True.

Note that when evaluating expressions in the Web UI Expression Builder, the variableFormat function must be evaluated on the server when using the asTable parameter.

String or Data Table

Yes

Yes

variableGroup(String context, String variable[, String schema])

Returns name of a group the variable belongs to or null if it doesn’t belong to any group.

String

Yes

No

variableReadable(String context, String variable [, String schema])

Returns true if context with path specified by context argument has variable specified by variable argument and this variable is readable by the caller.

Boolean

Yes

Yes

variableWritable(String context, String variable [, String schema])

Returns true if context with path specified by context argument has variable specified by variable argument and this variable is writable by the caller.

Boolean

Yes

Yes

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