General Guidelines
Variables and Arguments
In general terms of parameters in WF4, there are two main concepts: Variables and Arguments. Variables are used to store data within a task and Arguments are used to pass data in/out of a task. The concept of „binding" parameters has been replaced with the usage of variables and arguments.
Variables are to be used in a task whenever the need to store data is limited to the current task and the output/input of the task is not used anywhere else (for example another task).
Arguments are to be used whenever the input parameters of an activity are given by the user using a web-based application, (for example when executing a task in Portal) or if the output of an activity is to be returned and used outside of Flowster Designer application. (for example Portal).
Each activity has a predefined set of Input/Output parameters. Depending on the requirements and business scenarios, variables and arguments may be required.
Each Input parameter from each activity has an editor. The default editor is the Expression Editor which allows string values to be inserted. In the example below, the activity used is Length (check the Misc->Display Name property) from String Operations library . This activity has one input parameter, with an Expression editors that accept string values. The value "Flowster" was inserted directly in the Expression editor without the use of variables/IN arguments meaning that the value is now embedded in the task after check-in. This represents the basic value insertion for activity parameters.
If the value for the "InputString" parameter should not be embedded in the task and the value would be given on execution time, for example when executing the task from the User Portal, then an IN argument is defined for the "InputString" parameter. The arguments are defined in the Task Designer panel, Parameters section, Arguments tab. Each argument defined in this section should have a name, direction( IN for input values , OUT for output values, IN/OUT for arguments that are used for both input and output purposes). The argument type must match the desired input parameter's type from the activity (for example, for Length activity, the InputString parameter has a string type, so the defined argument InputString should have the same type).
Activity Properties
In general terms of activities properties, there are three main concepts: Enabled, Stop On Error and Track Outputs. These three properties are defined for each activity in flowster Activity Library.
The concept of Stop On Error and Enabled mechanisms are defined for Execution purposes.
The Track Outputs property is defined for Tracking Data panel.
Stop on Error
The default value for the Stop on Error property is set to "Yes". When dragging an activity in the Task Designer panel, the activity will have this property set to "Yes".
On execution (Home->(Execution section) Start button), if the Stop on Error property is set to "Yes" for an activity and an error or exception is thrown, the execution of the task stops on the activity that caused the error /exception to be thrown and the task is automatically aborted.
If Stop on Error property is set to "No", the error message is displayed in Tracking Data panel, but the execution of the task continues.
Enabled
The default value for the Enabled property is set to "Yes". When dragging an activity in the Task Designer panel, the activity will have this property set to "Yes".
On execution (Home->(Execution section) Start button), if the Enabled property is set to "Yes", the activity's logic block will be executed and if results are returned by the activity, they will be displayed in the Tracking Data panel.
If the Enabled property is set to "No", the activity's logic block will not be executed during execution and the activity block will appear faded in the Task Designer panel.
Track Outputs
The default value for the Track Outputs property is set to "No". When dragging an activity in the Task Designer panel, the activity will have this property set to "No".
On execution (Home->(Execution section) Start button), if the Track Outputs property is set to "No", the output results returned by the activity they will not be displayed in the Tracking Data panel.
if the Track Outputs property is set to "Yes", the output results returned by the activity they will be displayed in the Tracking Data panel.