Creating exposed process values (EPVs)

In IBM® Process Designer, you can create exposed process values (EPVs) to define a set of variables you want to expose to specific users. These variables can be modified by the users while instances of a process are running. For example, if you create a process to handle expense reimbursement, you may want to enable supervisors to change the allowed amounts for daily expenditures, or the dollar amount that coincides with various levels of approvers. By creating EPVs, you can provide this type of flexibility, allowing users to adjust specific variable values as constants, thereby affecting the flow of all running process instances, task assignments, and so on.

About this task

The EPV that is returned depends on whether Use New Values is set; it is unset by default.
  • If Use New Values is set, the tw.epv API returns the EPV that has an Effective On date that is in the past and is closest to the current time.
  • If Use New Values is unset, the tw.epv API uses the time that the task instance started, which means that it finds the EPV that has an Effective On date in the past and is closest to the time that the task instance started.
During snapshot migration, the EPV data can be copied from the previous snapshot to the current one. For more information, see the topic Snapshot and instance migration overview. To avoid unexpected behavior:
  • Check your settings to make sure the behavior is what you expect.
  • Set a default value for your EPV.
Note: The instructions in this help topic explain how to create a new EPV and expose it to a team whose members can manage the EPV and adjust its variable values. If you have an existing EPV that is not yet exposed, you must expose it to a team in IBM Process Designer and create a new snapshot in order to edit the default values. Otherwise, the EPV will not be usable. The EPV can only be edited by the team to which it is exposed. It cannot be edited by administrators. After the EPV is exposed to a specific team, you can change the content of the team at runtime using the regular team modification methods. For more information about EPVs, see the topic Managing exposed process values (EPVs).

Procedure

To create an EPV:

  1. Open IBM Process Designer.
  2. Expand Data and select Exposed Process Value. The New Exposed Process Value window opens.
  3. In the Name field, type a name for the value and click Finish. The EPV configuration view opens.
  4. Configure the EPV:
    1. In the Documentation field, enter a description of the EPV for the developers.
    2. To allow users to send feedback about this EPV, type an email address in the Feedback E-mail Contact field.

      The Manage Exposed Process Values page in the Process Admin Console includes a feedback link that uses this email address.

    3. In the External Description field, enter a description of the EPV for the users. The description that you provide here is displayed in the Manage Exposed Process Values page in the Process Admin Console.
  5. Add one or several variables to the EPV by applying the following steps:
    1. In the Exposed Process Value Variables section, click + to add a variable to this EPV.

      For example, if you want to enable users to adjust the dollar amounts that correspond with various levels of approvers for an expense reimbursement process, add a variable for each available level.

    2. In the Variable Details section, in the External Name field, type the name of the variable for the users. This name appears in the Variable List for this EPV in the Process Admin Console.
    3. In the Variable Name field, type the name of the variable for internal processing.
      Note: Variable names should start with a lowercase letter, with subsequent words capitalized like so: myVar. Do not use spaces in variable names. Variable names are case sensitive.
    4. In the External Description field, type the text to describe this variable to users. This description appears in the Variable List for this EPV in the Process Admin Console.
    5. Optional: In the Default Value text box, type a valid default for this variable.
    6. To enable in-progress tasks to use the updated value of this variable when users edits its value, select the Use New Values check box.
    7. To select a variable type, click Select... and select a business object or click New to create a new custom business object (variable type).
      Note: You should exercise caution when using a non-string type for EPV variables. The use of non-string types is not recommended and it can result in problems with JavaScript type conversion. If you must use a non-string type for EPV variables, see the "Example" section below.
  6. In the Exposing section, click Select to choose the team whose members can manage this EPV and adjust its variable values. The EPV can only be edited by the selected team. After the EPV is exposed to a specific team, you can change the content of the team at runtime using the regular team modification methods.

    By default, an EPV is not exposed to any team. You must expose an EPV by selecting a team in order to edit the values of the EPV. The EPV can only be edited by the team that is selected in the Process Admin Console. Administrators cannot edit the EPV. After the EPV is exposed to a specific team, you can change the content of the team at runtime using the regular team modification methods. For more information about EPVs, see the topic Managing exposed process values (EPVs).

  7. Click Save or Finish Editing.

Results

The EPV is created, you can link it to a process, service, or report.

You can refer to the name of the EPV and its variables like so: tw.epv.[epv_name].[epv_variable_name].

You can use the EPV in a decision gateway to control the flow of a process. You can also refer to the EPV from any JavaScript code in a linked process, such as the code within a server script service component.

Example

To use an integer or decimal type for an EPV variable (rather than the recommended string type), you should consider creating a corresponding local variable of the integer or decimal type. The operation should be performed on the local variable instead, for example

tw.local.number = tw.epv.myepvs.number; tw.local.number = tw.local.number + 1;

Alternatively, to use EPV variables in JavaScript code, you need to use type cast, for example

var mynumber = parseFloat(tw.epv.myepvs.number);
Parent topic: Business objects and variables
Related information:
Creating business objects in Process Designer