Process step preconditions

Most steps in a process can have a precondition. If the Precondition field is available, the process supports a precondition. This precondition determines whether the step runs. Like post-processing scripts, preconditions use JavaScript™ 1.7.

Note: The syntax for preconditions is similar to the syntax for post-processing scripts. See Post-processing scripts.

Preconditions return Boolean values. If the precondition returns True, the step runs as usual.

If the precondition returns anything other than True, the process skips that step. In the process request, the step is labeled "Precondition Failed." However, in this case, the process continues to run; the process follows the success links from that step as though the step succeeded.

The precondition has access to the same properties that the step does. Application processes have access to the following properties:
  • Application properties
  • Application process properties
  • Environment properties, including component environment properties
  • System properties
  • Output properties from previous steps. See Output properties.
Property availability depends on your context. See Property availability for information about which properties you can access.

After you run a process, you can see the properties that the process had access to by opening the process request and clicking the Properties tab.

To access a property, use the properties.get() command. For example, the following code retrieves the value of an application property:
properties.get("application/property1")
The following example precondition allows the step to run only if the application property property1 exists and is not null:
properties.get("application/property1") !== undefined && 
properties.get("application/property1") !== null && 
properties.get("application/property1") !== ""
Important: Do not use notation such as ${p:component.myProperty} in the precondition script. For example, to check the value of a component property in a component process, use properties.get("myProperty") == "myValue".
Precondition scripts can access the process properties. For example, if the process has a property that is named processProperty1, you can access that property with the following code:
properties.get("processProperty1")
Precondition scripts in component processes and generic processes can access the output properties of previous steps. For example, assume that the post-processing script of a step that is named Step1 specifies a property that is named OutputProp1. The following precondition script allows another step to run only if the value of this property is value1:
properties.get("Step1/OutputProp1") == "value1"
Preconditions have access to a property that is named hasFailures. This property is True if any of the steps in the process fail. It is undefined if no steps fail. For example, to run a step only if no other steps in the process fail, use the following precondition:
properties.get('hasFailures') == undefined