Working with Links

This chapter describes the links you can use in a workflow process. It includes these topics:

For more information For information about adding links to your workflow, see Workflow Modeler.

About links

The following types of explicit links are supported within a workflow:

Simple links
Condition links

Links are evaluated in order of precedence When an activity is linked to more than one other activity, the workflow engine uses precedence to determine which link to follow. Each link has a precedence number associated with it. In cases where more than one link expression might evaluate to true, the engine evaluates the links in precedence order, following all links that return true.

What happens when all link expressions return false You can mark a link as the default path to follow out of a particular activity. When all of the link expressions evaluate to false, the workflow engine follows the default link.

About scoped paths Scoped paths are pointers to application data that you can select visually in the Workflow Modeler. You can use scoped paths to select test values for link expressions or to specify the path for an activity's primary property. You can also copy scoped paths after the execution of a link.

For more information, see the chapter on working with scoped paths in Developing exteNd Director Applications.

Simple link

tbSimpleLink

A simple link represents a simple path from one activity to another. Simple links allow you to specify expressions that evaluate to true or false. When the expression for a simple link evaluates to true, the link is followed to the next activity. When the expression evaluates to false, the path is not followed.

Simple links provide an easy way to choose between multiple target activities. When an activity finishes processing, you can use expressions on simple links to determine which activity should be executed next.

For example, you could use expressions on Link 2 and Link 3 in the following workflow to determine whether Java activity 1 or Java activity 2 would be executed after User activity 1:

LinkExample1

If you do not specify an expression for a simple link, the workflow engine automatically moves to the target activity when the source activity finishes. For example, you would not need an expression on Link 2 in the following workflow, since the User activity1 activity has only one outgoing link:

LinkExample2

A Simple link has these properties:

Property Inspector tab	Property name	Description
Link	Name	A unique reference to this link that can be accessed in the flow.
	Description	A description of the link intended for the Workflow Modeler user.
	Copy Scoped Paths	Use to copy scoped data to another scope. The scope gets copied after the link is evaluated and before the target activity is executed. For more information, see Using scoped paths.
	Default	Select to make this path the default. Use if you have multiple links to or from an activity. The default is the path that is used if no other path evaluates to true.
	Expression	Use to build a logical expression that evaluates to true or false. If you do not build an expression, the path will evaluate to true and will be executed. For more information, see Creating link expressions.
	Precedence	Specify the order in which you want this link to be evaluated. Use if you have multiple links to or from an activity.
Design UI	Design UI properties control the design-time appearance of the link. For more information, see Setting object display properties.

Condition link

tbConditionLink

Like a simple link, a condition link represents a path from one activity to another. However, a condition link does not have an expression directly associated with it. Instead, it executes a condition macro created in the Rule Editor. A condition macro executes a set of conditions that contain reusable business logic:

ConditionLinkExample

Condition links evaluate to true or false. When a condition link evaluates to true, the link is followed to the next activity. When it evaluates to false, the path is not followed.

A Condition link has these properties:

Property Inspector tab	Property name	Description
Condition Link	Name	A unique reference to this link that can be accessed in the flow.
	Description	A description of the link intended for the WorkFlow Modeler user.
	Copy Scoped Paths	Use to copy scoped data to another scope. The scope gets copied after the link is evaluated and before the target activity is executed. For more information, see Using scoped paths.
	Default	Select to make this path the default. Use if you have multiple links to or from an activity. The default is the path that is used if no other path evaluates to true.
	Condition macro ID	The name of the condition macro XML descriptor, as specified in the Rule Editor. For more information, see the chapter on rule and macro editors in the Rules Guide.
	Precedence	Specify the order in which you want this link to be evaluated. Use if you have multiple links to or from an activity.
Design UI	Design UI properties control the design-time appearance of the link. For more information, see Setting object display properties.